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Al Jabbari YS, Dimitriadis K, Sufyan A, Zinelis S. Microstructural and mechanical characterization of six Co-Cr alloys made by conventional casting and selective laser melting. J Prosthet Dent 2024:S0022-3913(24)00434-7. [PMID: 38955601 DOI: 10.1016/j.prosdent.2024.06.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Revised: 06/12/2024] [Accepted: 06/13/2024] [Indexed: 07/04/2024]
Abstract
STATEMENT OF PROBLEM Three Co-Cr alloy types (Co-Cr-Mo, Co-Cr-W, and Co-Cr-Mo-W) have been commonly used in the fabrication of dental prostheses. These alloys can be manufactured using either conventional casting or selective laser melting (SLM) techniques. Nevertheless, research that directly compares these materials and/or manufacturing processes in terms of their microstructural and mechanical characteristics is sparse. PURPOSE The purpose of this in vitro study was to conduct microstructural and mechanical analysis via X-ray interpretation, optical microscopy, scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS), image analysis, X-ray diffraction (XRD), instrumented indentation testing (IIT), and 3-point bending testing to characterize Co-Cr-Mo, Co-Cr-W, and Co-Cr-Mo-W alloys produced through conventional casting and SLM. MATERIAL AND METHODS Six Co-Cr-based alloys were analyzed and divided into 3 types based on their elemental composition (Co-Cr-Mo, Co-Cr-W, and Co-Cr-Mo-W). Additionally, each group was categorized based on the manufacturing process used (casting or SLM). X-ray scans were used to assess porosity. The microstructures of the specimens were assessed through SEM/EDS examination and XRD analysis. IIT was used to determine the Martens hardness (HM) and elastic index (ηIT), while the elastic modulus (E) was estimated through the 3-point bending test. The mechanical properties were statistically analyzed using 2-way analysis of variance (ANOVA) and the Tukey multiple comparison post hoc test, with alloy type and manufacturing process as discriminating variables (α=.05). RESULTS All cast groups exhibited gross porosity, while no pores or other flaws were found in the SLM groups. Based on the XRD results, the crystalline structure of all Co-Cr specimens consisted of the face-centered cubic γ phase (γ-fcc), along with the hexagonal close-packed ε phase (ε-hcp) and Cr23C6 carbide. Different microstructures were identified between the cast and SLM alloys. Significant differences were identified for the mean standard deviation HM (ranging from 2601 ±94 N/mm2 to 3633 ±61 N/mm2) and mean ±standard deviation ηIT (ranging from 16.8 ±0.3% to 20.9 ±0.3%) among alloys prepared by the same manufacturing process, while all SLM alloys had statistically higher HM and ηIT results than their cast counterparts (P<.05). No statistically significant differences were identified for the mean ±standard deviation Eb (ranging from 170 ±25 GPa to 244 ±36 GPa) among the groups prepared with the same manufacturing process (P>.05), but the SLM alloys had significantly higher results (P<.05) than the cast alloys. CONCLUSIONS In general, the manufacturing procedure significantly affected the porosity, microstructure, and mechanical properties of the tested Co-Cr alloys. SLM decreased the internal porosity, provided a uniform microstructure, and improved the mechanical properties for all the tested alloy types.
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Affiliation(s)
- Youssef S Al Jabbari
- Director, Dental Biomaterials Research and Development Chair and Professor, Prosthetic Dental Sciences Department, College of Dentistry, King Saud University, Riyadh, Saudi Arabia.
| | - Konstantinos Dimitriadis
- Research fellow, Department of Biomaterials, School of Dentistry, National and Kapodistrian Universty of Athens, Athens, Greece
| | - Aref Sufyan
- Researcher, Dental Biomaterials Research and Development Chair, College of Dentistry, King Saud University, Riyadh, Saudi Arabia
| | - Spiros Zinelis
- Professor, Department of Biomaterials, School of Dentistry, National and Kapodistrian Universty of Athens, Athens, Greece and International Professor of Dental Biomaterials Research and Development Chair, King Saud University, Riyadh, Saudi Arabia
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Htat HL, Takaichi A, Kajima Y, Kittikundecha N, Kamijo S, Hanawa T, Wakabayashi N. Influence of stress-relieving heat treatments on the efficacy of Co-Cr-Mo-W alloy copings fabricated using selective laser melting. J Prosthodont Res 2024; 68:310-318. [PMID: 37438109 DOI: 10.2186/jpr.jpr_d_22_00283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/14/2023]
Abstract
Purpose This study aimed to evaluate the influence of stress-relieving heat treatments on the metal-ceramic bond strength and fitness accuracy of selective laser melting (SLM)-fabricated Co-Cr alloy copings.Methods SLM-manufactured Co-Cr samples were stress-relieved at 750 (Ht-750) and 1150 °C (Ht-1150). The microstructure, surface roughness, metal-ceramic bond strength, marginal and internal fit, Vickers hardness, and residual stress were then compared with those of the non-heat-treated group (As-built). The results were analyzed using one-way ANOVA and post-hoc tests (Tukey's or Student's t test) (P = 0.05).Results The microstructure of the Ht-1150 samples had a brittle oxide layer and lower surface roughness, resulting in significantly lower bond strength values than those of the other groups. The As-built group exhibited significantly lower marginal gap values than the Ht-750 and Ht-1150 groups. Therefore, the post-heat treatments degraded the marginal fitness. The surface residual stress in all sample groups were compressive because of the sandblasting effect. The compressive stresses were larger in Ht-1150 than in As-built and Ht-750 owing to their low hardness values.Conclusions Stress-relief annealing porcelain-fused-to-metal single crowns does not improve bond strength and degrades fitness accuracy because additional post-heat treatments induce thermal distortion. These findings are expected to facilitate the direct application of As-built SLM single crowns in dentistry to minimize post-manufacturing costs and time.
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Affiliation(s)
- Hein Linn Htat
- Department of Advanced Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Atsushi Takaichi
- Department of Advanced Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Yuka Kajima
- Department of Advanced Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Nuttaphon Kittikundecha
- Department of Conservative Dentistry and Prosthodontics, Faculty of Dentistry, Srinakharinwirot University, Bangkok, Thailand
| | - Shingo Kamijo
- Basic Oral Health Engineering, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Takao Hanawa
- Department of Metallic Biomaterials, Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, Tokyo, Japan
| | - Noriyuki Wakabayashi
- Department of Advanced Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
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Klimek L, Bułhak B, Śmielak B. A Comparison of the Structure and Selected Mechanical Properties of Cr/Co Alloys Obtained by Casting and Selective Laser Melting. J Funct Biomater 2024; 15:61. [PMID: 38535254 PMCID: PMC10970936 DOI: 10.3390/jfb15030061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 02/09/2024] [Accepted: 02/23/2024] [Indexed: 06/27/2024] Open
Abstract
Selective laser melting (SLM) technologies are becoming increasingly popular. The aim of the work is to compare the metallographic structure, hardness, and selected strength properties of alloys obtained by casting and by SLM, with a particular emphasis on fatigue strength. Twenty Cr/Co alloy bars were made by casting or SLM, and samples of appropriate dimensions were prepared for individual tests. The microstructures of the samples were tested by metallography, and then tested for hardness, impact strength, tensile strength, bending strength, and fatigue strength; they were also subjected to fracture after bending, tensile, fatigue, and impact tests, with the resulting fractures examined by scanning electron microscopy (SEM). Primary dendrites and small amounts of gas bubbles were present in the cast samples ground lengthwise. The SEM samples were more finer grained and uniform. Compared to the casting samples, the SLM samples demonstrated higher hardness, lower mean impact strength and higher tensile strength. The casting samples also displayed lower mean elongation values. The casting samples demonstrated slightly higher fatigue strength. The fractures of the casting samples showed an interdendritic character with clearly visible dendrites at the fracture, while those of the SLM samples were also intergranular, but finer grained. SLM generally results in better strength properties, while casting obtains slightly greater fatigue strength.
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Affiliation(s)
- Leszek Klimek
- Institute of Materials Science and Engineering, Lodz University of Technology, 90-924 Lodz, Poland;
| | - Barbara Bułhak
- Department of Dental Techniques, Medical University of Lodz, ul. Pomorska 251, 92-231 Lodz, Poland;
| | - Beata Śmielak
- Department of Prosthodontics, Medical University of Lodz, ul. Pomorska 251, 92-231 Lodz, Poland
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Kumar K, Das A, Prasad SB. Novel Bioactive Magnesium-Hopeite composite by friction stir processing for orthopedic implant applications. Proc Inst Mech Eng H 2023; 237:502-516. [PMID: 36892001 DOI: 10.1177/09544119231158837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/10/2023]
Abstract
Magnesium (Mg) shows excellent potential for orthopedic implant applications owing to its equivalent mechanical properties compared to cortical bone and its biocompatibility. However, the rapid degradation rate of magnesium and its alloys in the physiological environment results in losing their mechanical integrity before complete bone healing. In light of this, friction stir processing (FSP), a solid-state process, is used to fabricate Hopeite (Zn(PO4)2.4H2O) reinforced novel magnesium composite. As a result of the novel composite fabricated by FSP, grain refinement of the matrix phase occurs significantly. The samples were immersed in simulated body fluid (SBF) for in-vitro bioactivity and biodegradability tests. The corrosion behavior of pure Mg, FSP Mg, and FSP Mg-Hopeite composite samples was compared using electrochemical and immersion tests in SBF. It found that Mg-Hopeite composite has better corrosion resistance than FSP Mg and pure Mg. Because of grain refinement and the presence of secondary phase Hopeite in the composite, the mechanical properties and corrosion resistance improved. The bioactivity test was performed in the SBF environment, and a rapid apatite layer was formed on the surface of Mg-Hopeite composite samples during the test. Osteoblast-like MG63 cells were exposed to samples, and the MTT assay confirmed the non-toxicity of the FSP Mg-Hopeite composite. The wettability of the Mg-Hopeite composite was improved than pure Mg. The present research findings showed that the novel Mg-Hopeite composite fabricated by FSP is a promising candidate for orthopedic implant applications, unreported in the literature.
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Affiliation(s)
- Kundan Kumar
- Department of Production and Industrial Engineering, National Institute of Technology, Jamshedpur, Jharkhand, India
| | - Ashish Das
- Department of Production and Industrial Engineering, National Institute of Technology, Jamshedpur, Jharkhand, India
| | - Shashi Bhushan Prasad
- Department of Production and Industrial Engineering, National Institute of Technology, Jamshedpur, Jharkhand, India
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Zinelis S, Polychronis G, Papadopoulos F, Kokkinos C, Economou A, Panayi N, Papageorgiou SN, Eliades T. Mechanical and electrochemical characterization of 3D printed orthodontic metallic appliances after in vivo ageing. Dent Mater 2022; 38:1721-1727. [PMID: 36123188 DOI: 10.1016/j.dental.2022.09.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 09/07/2022] [Accepted: 09/08/2022] [Indexed: 11/03/2022]
Abstract
OBJECTIVES Three-dimensional (3D) printing technology is a promising technique for fabricating custom orthodontic metallic appliances. Aim of this study was to assess the effect of intraoral aging on the mechanical / electrochemical properties of 3D-printed orthodontic metallic appliances. METHODS Twelve molar orthodontic distalization appliances 3D-printed from cobalt chromium (Co-Cr) alloy were retrieved after intraoral use and twenty blocks fabricated under similar conditions were used as control. The samples' microstructural / elemental composition assessment was assessed with SEM/EDS, while their mechanical properties (modulus of elasticity [EIT], Martens hardness [HM] and the elastic index [ηIT]) were measured by instrumented indentation testing. Finally, the samples' electrochemical features were assessed with a potentiostat-connected cell arrangement in terms of open circuit potential (OCP), corrosion potential (Ez), current density (I300) and breaking potential (Epit). Results were analyzed by t-test / Mann-Whitney test (α = 0.05). RESULTS The used Co-Cr alloy was found to have a highly homogenous structure with no significant differences between retrieved and new specimens in HM (4037.7 ± 215.6 vs 4090.9 ± 259.8 N/mm2), EIT (120.0 ± 13.2 vs 123.8 ± 12.9 GPa), or nIT (28.4 ± 2.6 vs 28.6 ± 2.9 %) (P > 0.05 in all instances). Metallic surfaces retained the same oxidation tendency and oxide dissolution rate in passive region in both groups (P > 0.05 for OCP, Ez, and I300). However, intraorally-aged specimens had a significantly lower breakdown potential due to degraded protection efficacy of surface oxide (P = 0.003 for Epit). SIGNIFICANCE The tested 3D-printed Co-Cr orthodontic appliances present clinically-acceptable mechanical properties that remained unaffected by intraoral ageing, which however degraded the protection of surface oxide against pitting corrosion.
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Affiliation(s)
- Spiros Zinelis
- Department of Biomaterials, School of Dentistry, National and Kapodistrian University of Athens, Athens, Greece
| | - Georgios Polychronis
- Department of Biomaterials, School of Dentistry, National and Kapodistrian University of Athens, Athens, Greece
| | - Frixos Papadopoulos
- Laboratory of Analytical Chemistry, Department of Chemistry, National and Kapodistrian University of Athens, Athens, Greece
| | - Christos Kokkinos
- Laboratory of Analytical Chemistry, Department of Chemistry, National and Kapodistrian University of Athens, Athens, Greece
| | - Anastasios Economou
- Laboratory of Analytical Chemistry, Department of Chemistry, National and Kapodistrian University of Athens, Athens, Greece
| | - Nearchos Panayi
- Department of Dentistry, European University Cyprus, Nicosia, Cyprus; Clinic of Orthodontics and Pediatric Dentistry, Center of Dental Medicine, University of Zurich, Zurich, Switzerland
| | - Spyridon N Papageorgiou
- Clinic of Orthodontics and Pediatric Dentistry, Center of Dental Medicine, University of Zurich, Zurich, Switzerland
| | - Theodore Eliades
- Clinic of Orthodontics and Pediatric Dentistry, Center of Dental Medicine, University of Zurich, Zurich, Switzerland.
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Guo Y, Guo W. Study and numerical analysis of Von Mises stress of a new tumor-type distal femoral prosthesis comprising a peek composite reinforced with carbon fibers: finite element analysis. Comput Methods Biomech Biomed Engin 2022; 25:1663-1677. [PMID: 35094629 DOI: 10.1080/10255842.2022.2032681] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Research on carbon-fiber-reinforced polyetheretherketone (CF-PEEK/CFR-PEEK) as a bone tumor joint prosthesis remains limited. Herein we numerically determine the feasibility of CF-PEEK material containing 30% Wt carbon fiber (CF30-PEEK) as a material for the dual-action tumor-type distal femoral prosthesis. Use CT scan method to build a complete finite element model of the knee joint. Simulate the resection of the distal femoral tumor, and then reconstruct it with the dual-action tumor-type distal femoral prosthesis. The femoral condyle and extension rod components were simulated with cobalt chromium molybdenum (CoCrMo), PEEK and CF30-PEEK materials respectively. When simulating the standing state, a vertical stress of 700 N is applied to the femoral head. When simulating the squatting state, a vertical stress of 2800 N is applied to the femoral head. The displacement and rotation angle of each node of the distal tibia are fully restrained in three directions (X-axis, Y-axis, Z-axis). We examined the stress magnitude, stress distribution, and stability of the prosthesis and each of its components by means of finite element analysis (FE analysis). The FE analysis results show: after replacing the distal femur and the extension rod with CF30-PEEK material, the stress is still evenly distributed, and the average stress is significantly reduced. In addition, the stability is similar to CoCrMo material. Therefore, CF30-PEEK is an appropriate material for this type of prosthesis.
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Affiliation(s)
- Yu Guo
- Musculoskeletal Tumor Center, Peking University People's Hospital, Beijing, People's Republic of China.,Beijing Key Laboratory of Musculoskeletal Tumor, Beijing, People's Republic of China
| | - Wei Guo
- Musculoskeletal Tumor Center, Peking University People's Hospital, Beijing, People's Republic of China.,Beijing Key Laboratory of Musculoskeletal Tumor, Beijing, People's Republic of China
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Corrosion of Additively Manufactured Metallic Components: A Review. ARABIAN JOURNAL FOR SCIENCE AND ENGINEERING 2022. [DOI: 10.1007/s13369-021-06481-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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Effects of heat treatment on the microstructure, residual stress, and mechanical properties of Co-Cr alloy fabricated by selective laser melting. J Mech Behav Biomed Mater 2021; 126:105051. [PMID: 34959095 DOI: 10.1016/j.jmbbm.2021.105051] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 12/10/2021] [Accepted: 12/14/2021] [Indexed: 11/24/2022]
Abstract
The mechanical properties and residual stress of dental Co-Cr-Mo (CCM) alloy depend on the manufacturing and post-processing methods, which affect the prognosis of dental prostheses. Two CCM alloys manufactured by casting and selective laser melting (SLM) were compared, and the effect of heat treatment temperature for CCM alloys manufactured by SLM method was evaluated. Specimens were fabricated by casting (Cast Co-Cr) and SLM (SLM Co-Cr). SLM Co-Cr specimens were heat treated at 750, 950, and 1150 °C to compare their properties. Microstructures were analyzed via scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and electron backscattered diffraction (EBSD), and the residual stress was measured via x-ray diffraction (XRD). Mechanical properties were evaluated by a Vickers hardness test and a tensile test; fractography was performed after this. The SLM Co-Cr group exhibited a decrease in porosity, grain size, increase in solid solution limit, and high residual stress compared to Cast Co-Cr; the ultimate tensile strength, yield strength, and hardness were also higher. The microstructures, residual stresses, and mechanical properties differed significantly depending on the heat treatment, and the strength and hardness showed a tendency inverse to that of the elongation. Type I residual stresses mostly decreased after 750 °C heat treatment, however type II and III residual stresses remained even after 1150 °C heat treatment. SLM presented superior mechanical properties to casting. Considering the reduction of tensile residual stress and increased ductility, CCM alloys should be heat treated at a temperature of 950 °C or higher.
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Mechanical Properties of Dental Alloys According to Manufacturing Process. MATERIALS 2021; 14:ma14123367. [PMID: 34204569 PMCID: PMC8235053 DOI: 10.3390/ma14123367] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 06/05/2021] [Accepted: 06/14/2021] [Indexed: 11/17/2022]
Abstract
The purpose of this study is to investigate the effect of the fabrication method of dental prosthesis on the mechanical properties. Casting was produced using the lost wax casting method, and milling was designed using a CAD/CAM program. The 3D printing method used the SLS technique to create a three-dimensional structure by sintering metal powder with a laser. When making the specimen, the specimen was oriented at 0, 30, 60, and 90 degrees. All test specimens complied with the requirements of the international standard ISO 22674 for dental alloys. Tensile strength was measured for yield strength, modulus of elasticity and elongation by applying a load until fracture of the specimen at a crosshead speed of 1.5 ± 0.5 mm/min (n = 6, modulus of elasticity n = 3). After the tensile test, the cross section of the fractured specimen was observed with a scanning electron microscope, and the statistics of the data were analyzed with a statistical program SPSS (IBM Corp. Released 2020. IBM SPSS Statistics for Windows, Version 27.0. Armonk, NY, USA: IBM Corp.) and using Anova and multiple comparison post-tests (scheffe method). The yield strength was the highest at 1042 MPa at an angle of 0 degrees in the specimen produced by 3D printing method, and the elongation was the highest at 14% at an angle of 90 degrees in the specimen produced by 3D printing method. The modulus of elasticity was the highest at 235 GPa in the milled specimen. In particular, the 3D printing group showed a difference in yield strength and elongation according to the build direction. The introduction of various advanced technologies and digital equipment is expected to bring high prospects for the growth of the dental market.
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Kabir H, Munir K, Wen C, Li Y. Recent research and progress of biodegradable zinc alloys and composites for biomedical applications: Biomechanical and biocorrosion perspectives. Bioact Mater 2021; 6:836-879. [PMID: 33024903 PMCID: PMC7530311 DOI: 10.1016/j.bioactmat.2020.09.013] [Citation(s) in RCA: 71] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 09/16/2020] [Accepted: 09/17/2020] [Indexed: 12/22/2022] Open
Abstract
Biodegradable metals (BMs) gradually degrade in vivo by releasing corrosion products once exposed to the physiological environment in the body. Complete dissolution of biodegradable implants assists tissue healing, with no implant residues in the surrounding tissues. In recent years, three classes of BMs have been extensively investigated, including magnesium (Mg)-based, iron (Fe)-based, and zinc (Zn)-based BMs. Among these three BMs, Mg-based materials have undergone the most clinical trials. However, Mg-based BMs generally exhibit faster degradation rates, which may not match the healing periods for bone tissue, whereas Fe-based BMs exhibit slower and less complete in vivo degradation. Zn-based BMs are now considered a new class of BMs due to their intermediate degradation rates, which fall between those of Mg-based BMs and Fe-based BMs, thus requiring extensive research to validate their suitability for biomedical applications. In the present study, recent research and development on Zn-based BMs are reviewed in conjunction with discussion of their advantages and limitations in relation to existing BMs. The underlying roles of alloy composition, microstructure, and processing technique on the mechanical and corrosion properties of Zn-based BMs are also discussed.
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Affiliation(s)
- Humayun Kabir
- School of Engineering, RMIT University, Melbourne, Victoria, 3001, Australia
| | - Khurram Munir
- School of Engineering, RMIT University, Melbourne, Victoria, 3001, Australia
| | - Cuie Wen
- School of Engineering, RMIT University, Melbourne, Victoria, 3001, Australia
| | - Yuncang Li
- School of Engineering, RMIT University, Melbourne, Victoria, 3001, Australia
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Hong MH, Lee DH, Hanawa T, Kwon TY. Comparison of microstructures and mechanical properties of 3 cobalt-chromium alloys fabricated with soft metal milling technology. J Prosthet Dent 2020; 127:489-496. [PMID: 33303192 DOI: 10.1016/j.prosdent.2020.07.037] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 07/25/2020] [Accepted: 07/27/2020] [Indexed: 10/22/2022]
Abstract
STATEMENT OF PROBLEM Although several manufacturers market soft metal milling blanks and systems, comprehensive comparative studies of differences in properties across commercially available soft metal milling alloys are lacking. PURPOSE The purpose of this in vitro study was to compare the microstructures and mechanical properties of 3 soft metal milling cobalt-chromium (Co-Cr) alloys (Ceramill Sintron, Soft Metal, and Sintermetall). MATERIAL AND METHODS Disk-shaped specimens (for surface characterization and hardness test) and dumbbell-shaped specimens (for tensile test as per International Organization for Standardization (ISO) 22674) were prepared by following each soft metal milling manufacturer's instructions. The crystal structures and microstructures of the 3 alloys were evaluated with optical microscopy, X-ray diffractometry (XRD), and scanning electron microscopy with electron backscattered diffraction (EBSD). The mechanical properties were investigated with a tensile test and Vickers hardness test (n=6). The results of the mechanical (tensile and hardness) tests were analyzed with 1-way ANOVA and the post hoc Tukey multiple comparison test (α=.05). RESULTS The Sintermetall specimen showed a finer microstructure and more porosity than the other 2 alloys. The XRD and EBSD analyses showed that the γ (face-centered cubic, fcc) matrix phase was predominant in the Ceramill Sintron alloy and the ε (hexagonal close-packed, hcp) matrix phase was predominant in the Soft Metal alloy. The Sintermetall alloy showed a slightly higher amount of ε phase than γ phase, with more chromium carbide formation than the other 2 alloys. The Ceramill Sintron alloy showed a significantly higher tensile strength than the other 2 alloys (P<.05), but a significantly lower 2% offset yield strength than the other 2 alloys (P<.05). The highest elongation was found in the Ceramill Sintron alloy, followed by the Sintermetall and Soft Metal alloys. The elastic modulus was the highest in the Sintermetall alloy, followed by the Soft Metal and Ceramill Sintron alloys. No significant differences in Vickers hardness values were detected among the 3 alloys (P=.263). CONCLUSIONS The different commercially available soft metal milling blanks and systems produced dissimilar alloys in terms of crystal structures and microstructures and, as a result, different mechanical properties.
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Affiliation(s)
- Min-Ho Hong
- Assistant Professor, Department of Dental Laboratory Science, College of Health Sciences, Catholic University of Pusan, Busan, Republic of Korea
| | - Du-Hyeong Lee
- Associate Professor, Department of Prosthodontics, School of Dentistry, Kyungpook National University, Daegu, Republic of Korea
| | - Takao Hanawa
- Professor, Department of Metallic Materials, Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, Tokyo, Japan
| | - Tae-Yub Kwon
- Professor, Department of Dental Biomaterials, School of Dentistry, Kyungpook National University, Daegu, Republic of Korea.
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Lee WF, Wang JC, Hsu CY, Peng PW. Microstructure, mechanical properties, and retentive forces of cobalt-chromium removable partial denture frameworks fabricated by selective laser melting followed by heat treatment. J Prosthet Dent 2020; 127:115-121. [PMID: 33234303 DOI: 10.1016/j.prosdent.2020.06.038] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 06/22/2020] [Accepted: 06/23/2020] [Indexed: 10/22/2022]
Abstract
STATEMENT OF PROBLEM The effect of heat treatment on the microstructure and mechanical properties of cobalt-chromium (Co-Cr) removable partial denture (RPD) frameworks fabricated by selective laser melting (SLM) is not well understood. PURPOSE The purpose of this in vitro study was to evaluate the suitability of SLM-fabricated Co-Cr alloys followed by heat treatment as a framework for RPDs by determining the microstructure and mechanical properties. MATERIAL AND METHODS Dumbbell specimens and RPD frameworks were fabricated by using SLM followed by heat treatment. The effects of the heat treatment on the microstructure were studied by using optical microscopy, scanning electron microscopy (SEM), and X-ray diffraction (XRD). Tensile and insertion and removal tests were performed to study the mechanical responses of selective laser melting followed by heat treatment specimens, including the ultimate tensile strength (UTS), 0.2% yield strength (0.2% YS), elongation (E), and retentive forces. Specimens fabricated by using the traditional lost-wax process were used as a control (casting) group. RESULTS X-ray diffraction indicated that the γ-face-centered cubic phase dominated SLM and selective laser melting followed by heat treatment specimens. Results from optical microscopy and SEM showed microstructural changes under different fabrication and postprocessing heat treatments; it was difficult to observe the grain boundary in the SLM group, whereas submicrometer-scale grains had formed in the selective laser melting followed by heat treatment group. The selective laser melting followed by heat treatment group exhibited the highest elongation and retentive forces compared with the casting and SLM groups. CONCLUSIONS SLM increased the mechanical properties of Co-Cr alloys. Postprocessing heat treatment further enhanced the tensile ductility. It is suggested that SLM followed by heat treatment is an efficient strategy for fabricating RPD frameworks.
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Affiliation(s)
- Wei-Fang Lee
- Assistant Professor, School of Dental Technology, Taipei Medical University, Taipei, Taiwan, Republic of China
| | - Jia-Chang Wang
- Professor, Department of Mechanical Engineering, National Taipei University of Technology, Taipei, Taiwan, Republic of China
| | - Ching-Ying Hsu
- Dental Technician, Department of Dentistry, Taipei Medical University Hospital, Taipei, Taiwan, Republic of China
| | - Pei-Wen Peng
- Associate Professor, School of Dental Technology, Taipei Medical University, Taipei, Taiwan, Republic of China.
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Control of Microstructure for Co-Cr-Mo Fibers Fabricated by Unidirectional Solidification. CRYSTALS 2019. [DOI: 10.3390/cryst10010011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Co-Cr-Mo alloy fibers of 2 mm in diameter were fabricated from the melt at 1, 2, and 5 mm/min growth rates by unidirectional solidification using an alloy-micro-pulling-down (A-µ-PD) method to control the microstructure. All elements, Co, Cr, and Mo, were distributed in stripes elongated along the growth direction due to constitutional undercooling. Both Co-Cr-Mo fibers fabricated at 2 and 5 mm/min growth rates were composed of the γ phase with a face-centered cubic structure (fcc-γ phase) and ε-phase with a hexagonal close-packed structure (hcp-ε phase), and the ratio of the fcc-γ phase in the fiber fabricated at 5 mm/min growth rate was higher than that in the fiber fabricated at 2 mm/min. The results suggest that a faster growth rate increases the ratio of the fcc-γ phase in the Co-Cr-Mo fiber fabricated by unidirectional solidification.
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Takaichi A, Kajima Y, Kittikundecha N, Htat HL, Wai Cho HH, Hanawa T, Yoneyama T, Wakabayashi N. Effect of heat treatment on the anisotropic microstructural and mechanical properties of Co-Cr-Mo alloys produced by selective laser melting. J Mech Behav Biomed Mater 2019; 102:103496. [PMID: 31669983 DOI: 10.1016/j.jmbbm.2019.103496] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 10/08/2019] [Accepted: 10/13/2019] [Indexed: 11/30/2022]
Abstract
The purpose of this study was to evaluate the effect of heat treatment on the anisotropy of the microstructure and mechanical properties of cobalt-chromium-molybdenum (Co-Cr-Mo) alloys fabricated by selective laser melting (SLM). Dumbbell samples were fabricated with the axes deviating from the build direction by 0° (0°-sample), 45° (45°-sample), or 90° (90°-sample) and were subjected to heat treatment at various temperatures (750, 900, 1050, or 1150 °C) for 6 h. In samples heat-treated at 750, 900, and 1050 °C, the microstructures exhibited columnar grains with a <001> fiber texture along the build direction, the same as in the as-built state. The mechanical properties showed anisotropy; the 0.2% offset yield strengths (YS) of the 0°-samples were lower than those of the 90°-samples, and the elongations of the 0°-samples were significantly higher than those of the 45°- and 90°-samples. By contrast, in samples heated to 1150 °C for 6 h, the anisotropic columnar grains completely disappeared, and equiaxed grains with random orientations were found in all samples, indicating that recrystallization had occurred. Moreover, the specific microstructures and texture generated during SLM disappeared. Regarding tensile properties, the initially strong anisotropy exhibited by the as-SLM samples was significantly reduced. Thus, heat treatment at the recrystallization temperature produced uniform equiaxed grains with random texture, which contributed to reducing the mechanical anisotropy of the SLMed Co-Cr-Mo alloys.
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Affiliation(s)
- Atsushi Takaichi
- Removable Partial Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan
| | - Yuka Kajima
- Removable Partial Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan; Department of Dental Materials, Nihon University School of Dentistry, 1-8-13 Kanda-Surugadai, Chiyoda-ku, Tokyo, 101-8310, Japan.
| | - Nuttaphon Kittikundecha
- Removable Partial Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan
| | - Hein Linn Htat
- Removable Partial Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan
| | - Hla Htoot Wai Cho
- Removable Partial Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan
| | - Takao Hanawa
- Department of Metallic Biomaterials, Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, 2-3-10 Kanda-surugadai, Chiyoda-ku, Tokyo, 101-0062, Japan
| | - Takayuki Yoneyama
- Department of Dental Materials, Nihon University School of Dentistry, 1-8-13 Kanda-Surugadai, Chiyoda-ku, Tokyo, 101-8310, Japan
| | - Noriyuki Wakabayashi
- Removable Partial Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan
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Magnesium matrix nanocomposites for orthopedic applications: A review from mechanical, corrosion, and biological perspectives. Acta Biomater 2019; 96:1-19. [PMID: 31181263 DOI: 10.1016/j.actbio.2019.06.007] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 05/28/2019] [Accepted: 06/05/2019] [Indexed: 02/06/2023]
Abstract
Magnesium (Mg) and some of its alloys have attracted extensive interests for biomedical applications as they exhibit biodegradability and low elastic modulus that is closer to natural bones than the currently used metallic implant materials such as titanium (Ti) and its alloys, stainless steels, and cobalt-chromium (Co-Cr) alloys. However, the rapid degradation of Mg alloys and loss of their mechanical integrity before sufficient bone healing impede their clinical application. Our literature review shows that magnesium matrix nanocomposites (MMNCs) reinforced with nanoparticles possess enhanced strength, high corrosion resistance, and good biocompatibility. This article provides a detailed analysis of the effects of nanoparticle reinforcements on the mechanical properties, corrosion behavior, and biocompatibility of MMNCs as promising biodegradable implant materials. The governing equations to quantitatively predict the mechanical properties and underlying synergistic strengthening mechanisms in MMNCs are elucidated. The potential, recent advances, challenges and future research directions in relation to nanoparticles reinforced MMNCs are highlighted. STATEMENT OF SIGNIFICANCE: Critically reviewing magnesium metal matrix nanocomposites (MMNCs) for the biomedical application. Clear definitions of strengthening mechanisms using reinforcement particle in the magnesium matrix, as there were controversial in governing equations of strengthening parameters. Providing better understanding of the effect of particle size, volume fraction, interfacial bonding, and uniform dispersion of reinforcement particles on MMNCs.
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16
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Vickers microhardness and indentation creep studies for erbium-doped ZnO nanoparticles. SN APPLIED SCIENCES 2019. [DOI: 10.1007/s42452-019-0559-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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17
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Impact of minor alloying with C and Si on the precipitation behavior and mechanical properties of N-doped Co–Cr alloy dental castings. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2018; 92:112-120. [DOI: 10.1016/j.msec.2018.06.035] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2017] [Revised: 04/19/2018] [Accepted: 06/16/2018] [Indexed: 11/22/2022]
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18
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CoCrWCu alloy with antibacterial activity fabricated by selective laser melting: Densification, mechanical properties and microstructural analysis. POWDER TECHNOL 2018. [DOI: 10.1016/j.powtec.2017.11.018] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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19
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Effect of nitrogen on the microstructure and mechanical properties of Co-33Cr-9W alloys prepared by dental casting. J Mech Behav Biomed Mater 2017; 77:693-700. [PMID: 29102894 DOI: 10.1016/j.jmbbm.2017.10.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 09/16/2017] [Accepted: 10/10/2017] [Indexed: 11/24/2022]
Abstract
The effect of nitrogen concentration on the mechanical properties of Co-33Cr-9W alloy dental castings fabricated using the "high-Cr and high-N" concept was investigated. Microstructural analysis was performed on the alloys, and findings were discussed in relation to the mechanical properties. Owing to their high nitrogen concentrations (0.25-0.35wt%), all alloys prepared exhibited face-centered cubic (fcc) γ-phase matrices with a-few-millimeter grains consisting of dendritic substructures. Strain-induced martensitic transformations to produce hexagonal close-packed (hcp) ε-phases were not identified under tensile deformation. The precipitation of the intermetallic σ-phase was identified at the interdendritic regions where solidification segregation of Cr and W occurred. The size and chemical composition of this σ-phase did not vary with the bulk nitrogen concentration. Adding nitrogen to the alloys did not alter their tensile yield stress or Vickers hardness values significantly, suggesting that the nitrogen strengthening effect is affected by the manufacturing route as well as local chemistry that is involved in the microstructural evolution during solidification. The tensile ductility, on the other hand, increased with an increase in nitrogen concentration; the alloy with 0.35wt% nitrogen exhibited 21% elongation with a high 0.2% proof stress (589MPa). This significant improvement in ductility was likely caused by the reduction in the amount of σ-phase precipitates at the interdendritic regions following the addition of nitrogen.
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Koutsoukis T, Zinelis S, Eliades G, Al-Wazzan K, Rifaiy MA, Al Jabbari YS. Selective Laser Melting Technique of Co-Cr Dental Alloys: A Review of Structure and Properties and Comparative Analysis with Other Available Techniques. J Prosthodont 2017; 24:303-12. [PMID: 26129918 DOI: 10.1111/jopr.12268] [Citation(s) in RCA: 172] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/03/2014] [Indexed: 11/27/2022] Open
Abstract
PURPOSE The aim of this study was to review the effect of selective laser melting (SLM) procedure on the properties of dental structures made of Co-Cr alloys and to evaluate its quality and compare it to those produced by conventional casting and milling fabrication techniques. MATERIALS AND METHODS A computerized database search using PubMed and Scopus was conducted for peer-reviewed scientific research studies regarding the use of SLM in Co-Cr dental alloys with no restrictions for publication years. The search engines provided hundreds of results, and only 48 scientific research papers, case studies, or literature reviews were considered relevant for this review. RESULTS The innovative manufacturing concept of SLM offers many advantages compared with casting and milling fabrication techniques. SLM provides different microstructure from casting and milling with minimal internal porosity and internal fitting, marginal adaptation, and comparable bond strength to porcelain. Mechanical and electrochemical properties of SLM structures are enhanced compared to cast, while clinical longevity of single-metal ceramic crowns is comparable to Au-Pt dental alloy. CONCLUSION The SLM technique provides dental prosthetic restorations more quickly and less expensively without compromising their quality compared with restorations prepared by casting and milling techniques. CLINICAL SIGNIFICANCE The current SLM devices provide metallic restorations made of Co-Cr alloys for removable and fixed partial dentures without compromising the alloy or restoration properties at a fraction of the time and cost, showing great potential to replace the aforementioned fabrication techniques in the long term; however, further clinical studies are essential to increase the acceptance of this technology by the worldwide dental community.
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Affiliation(s)
- Theodoros Koutsoukis
- Dental Biomaterials Research and Development Chair, College of Dentistry, King Saud University, Riyadh, Saudi Arabia
| | - Spiros Zinelis
- Dental Biomaterials Research and Development Chair, College of Dentistry, King Saud University, Riyadh, Saudi Arabia.,Department of Biomaterials, School of Dentistry, National and Kapodistrian University of Athens, Athens, Greece
| | - George Eliades
- Department of Biomaterials, School of Dentistry, National and Kapodistrian University of Athens, Athens, Greece
| | - Khalid Al-Wazzan
- Dental Biomaterials Research and Development Chair, College of Dentistry, King Saud University, Riyadh, Saudi Arabia.,Department of Prosthetic Dental Sciences, College of Dentistry, King Saud University, Riyadh, Saudi Arabia
| | - Mohammed Al Rifaiy
- Dental Biomaterials Research and Development Chair, College of Dentistry, King Saud University, Riyadh, Saudi Arabia.,Department of Prosthetic Dental Sciences, College of Dentistry, King Saud University, Riyadh, Saudi Arabia
| | - Youssef S Al Jabbari
- Dental Biomaterials Research and Development Chair, College of Dentistry, King Saud University, Riyadh, Saudi Arabia.,Department of Prosthetic Dental Sciences, College of Dentistry, King Saud University, Riyadh, Saudi Arabia
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Li J, Chen C, Liao J, Liu L, Ye X, Lin S, Ye J. Bond strengths of porcelain to cobalt-chromium alloys made by casting, milling, and selective laser melting. J Prosthet Dent 2017; 118:69-75. [DOI: 10.1016/j.prosdent.2016.11.001] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Revised: 11/01/2016] [Accepted: 11/01/2016] [Indexed: 11/30/2022]
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22
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Kim JT, Hong SH, Park HJ, Kim YS, Suh JY, Lee JK, Park JM, Maity T, Eckert J, Kim KB. Deformation mechanisms to ameliorate the mechanical properties of novel TRIP/TWIP Co-Cr-Mo-(Cu) ultrafine eutectic alloys. Sci Rep 2017; 7:39959. [PMID: 28067248 PMCID: PMC5220307 DOI: 10.1038/srep39959] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 11/28/2016] [Indexed: 11/09/2022] Open
Abstract
In the present study, the microstructural evolution and the modulation of the mechanical properties have been investigated for a Co-Cr-Mo (CCM) ternary eutectic alloy by addition of a small amount of copper (0.5 and 1 at.%). The microstructural observations reveal a distinct dissimilarity in the eutectic structure such as a broken lamellar structure and a well-aligned lamellar structure and an increasing volume fraction of Co lamellae as increasing amount of copper addition. This microstructural evolution leads to improved plasticity from 1% to 10% without the typical tradeoff between the overall strength and compressive plasticity. Moreover, investigation of the fractured samples indicates that the CCMCu alloy exhibits higher plastic deformability and combinatorial mechanisms for improved plastic behavior. The improved plasticity of CCMCu alloys originates from several deformation mechanisms; i) slip, ii) deformation twinning, iii) strain-induced transformation and iv) shear banding. These results reveal that the mechanical properties of eutectic alloys in the Co-Cr-Mo system can be ameliorated by micro-alloying such as Cu addition.
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Affiliation(s)
- J T Kim
- Hybrid Materials Center (HMC), Faculty of Nanotechnology and Advanced Materials Engineering, Sejong University, 209 Neugdong-ro, Gwangjin-gu, Seoul 143-747, Republic of Korea
| | - S H Hong
- Hybrid Materials Center (HMC), Faculty of Nanotechnology and Advanced Materials Engineering, Sejong University, 209 Neugdong-ro, Gwangjin-gu, Seoul 143-747, Republic of Korea
| | - H J Park
- Hybrid Materials Center (HMC), Faculty of Nanotechnology and Advanced Materials Engineering, Sejong University, 209 Neugdong-ro, Gwangjin-gu, Seoul 143-747, Republic of Korea
| | - Y S Kim
- Hybrid Materials Center (HMC), Faculty of Nanotechnology and Advanced Materials Engineering, Sejong University, 209 Neugdong-ro, Gwangjin-gu, Seoul 143-747, Republic of Korea
| | - J Y Suh
- High Temperature Energy Materials Research Center, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seoungbuk-gu, Seoul 136-791, Republic of Korea
| | - J K Lee
- Division of Advanced Materials Engineering, Kongju National University, Cheonan 330-717, Republic of Korea
| | - J M Park
- Global Technology Center, Samsung Electronics Co., Ltd, 129 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do 443-742, Republic of Korea
| | - T Maity
- Department Materials Physics, Montanuniversität Leoben, Jahnstraße 12, A-8700 Leoben, Austria
| | - J Eckert
- Department Materials Physics, Montanuniversität Leoben, Jahnstraße 12, A-8700 Leoben, Austria.,Erich Schmid Institute of Materials Science, Austrian Academy of Sciences, Jahnstraße 12, A-8700 Leoben, Austria
| | - K B Kim
- Hybrid Materials Center (HMC), Faculty of Nanotechnology and Advanced Materials Engineering, Sejong University, 209 Neugdong-ro, Gwangjin-gu, Seoul 143-747, Republic of Korea
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Microstructures and Mechanical Properties of Co-Cr Dental Alloys Fabricated by Three CAD/CAM-Based Processing Techniques. MATERIALS 2016; 9:ma9070596. [PMID: 28773718 PMCID: PMC5456947 DOI: 10.3390/ma9070596] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/25/2016] [Revised: 07/12/2016] [Accepted: 07/15/2016] [Indexed: 11/29/2022]
Abstract
The microstructures and mechanical properties of cobalt-chromium (Co-Cr) alloys produced by three CAD/CAM-based processing techniques were investigated in comparison with those produced by the traditional casting technique. Four groups of disc- (microstructures) or dumbbell- (mechanical properties) specimens made of Co-Cr alloys were prepared using casting (CS), milling (ML), selective laser melting (SLM), and milling/post-sintering (ML/PS). For each technique, the corresponding commercial alloy material was used. The microstructures of the specimens were evaluated via X-ray diffractometry, optical and scanning electron microscopy with energy-dispersive X-ray spectroscopy, and electron backscattered diffraction pattern analysis. The mechanical properties were evaluated using a tensile test according to ISO 22674 (n = 6). The microstructure of the alloys was strongly influenced by the manufacturing processes. Overall, the SLM group showed superior mechanical properties, the ML/PS group being nearly comparable. The mechanical properties of the ML group were inferior to those of the CS group. The microstructures and mechanical properties of Co-Cr alloys were greatly dependent on the manufacturing technique as well as the chemical composition. The SLM and ML/PS techniques may be considered promising alternatives to the Co-Cr alloy casting process.
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24
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Qian C, Wu X, Zhang F, Yu W. Electrochemical impedance investigation of Ni-free Co-Cr-Mo and Co-Cr-Mo-Ni dental casting alloy for partial removable dental prosthesis frameworks. J Prosthet Dent 2016; 116:112-8. [DOI: 10.1016/j.prosdent.2015.12.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Revised: 12/07/2015] [Accepted: 12/07/2015] [Indexed: 11/28/2022]
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25
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Mengucci P, Barucca G, Gatto A, Bassoli E, Denti L, Fiori F, Girardin E, Bastianoni P, Rutkowski B, Czyrska-Filemonowicz A. Effects of thermal treatments on microstructure and mechanical properties of a Co–Cr–Mo–W biomedical alloy produced by laser sintering. J Mech Behav Biomed Mater 2016; 60:106-117. [DOI: 10.1016/j.jmbbm.2015.12.045] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Revised: 12/29/2015] [Accepted: 12/30/2015] [Indexed: 11/29/2022]
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Developing high strength and ductility in biomedical Co-Cr cast alloys by simultaneous doping with nitrogen and carbon. Acta Biomater 2016; 31:435-447. [PMID: 26678827 DOI: 10.1016/j.actbio.2015.12.011] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2015] [Revised: 12/04/2015] [Accepted: 12/08/2015] [Indexed: 11/24/2022]
Abstract
There is a strong demand for biomedical Co-Cr-based cast alloys with enhanced mechanical properties for use in dental applications. We present a design strategy for development of Co-Cr-based cast alloys with very high strength, comparable to that of wrought Co-Cr alloys, without loss of ductility. The strategy consists of simultaneous doping of nitrogen and carbon, accompanied by increasing of the Cr content to increase the nitrogen solubility. The strategy was verified by preparing Co-33Cr-9W-0.35N-(0.01-0.31)C (mass%) alloys. We determined the carbon concentration dependence of the microstructures and their mechanical properties. Metal ion release of the alloys in an aqueous solution of 0.6% sodium chloride (NaCl) and 1% lactic acid was also evaluated to ensure their corrosion resistance. As a result of the nitrogen doping, the formation of a brittle σ-phase, a chromium-rich intermetallic compound, was significantly suppressed. Adding carbon to the alloys resulted in finer-grained microstructures and carbide precipitation; accordingly, the strength increased with increasing carbon concentration. The tensile ductility, on the other hand, increased with increasing carbon concentration only up to a point, reaching a maximum at a carbon concentration of ∼0.1mass% and decreasing with further carbon doping. However, the alloy with 0.31mass% of carbon exhibited 14% elongation and also possessed very high strength (725MPa in 0.2% proof stress). The addition of carbon did not significantly degrade the corrosion resistance. The results show that our strategy realizes a novel high-strength Co-Cr-based cast alloy that can be produced for advanced dental applications using a conventional casting procedure. STATEMENT OF SIGNIFICANCE The present study suggested a novel alloy design concept for realizing high-strength Co-Cr-based cast alloys. The proposed strategy is beneficial from the practical point of view because it uses conventional casting approach-a simpler, more cost-effective, industrially friendly manufacturing process than other manufacturing processes such as thermomechanical processing or powder metallurgy. The developed alloys showed the excellent strength-ductility balance and significantly high strength comparable to that of wrought Co-Cr-Mo alloys, while maintaining acceptable ductility and good corrosion resistance. We described the relationship between microstructures and mechanical and corrosion prosperities of the developed alloys; this provides the fundamental aspect of the proposed strategy and will be helpful for further investigations or industrial realization of the proposed strategy.
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Lu Y, Wu S, Gan Y, Zhang S, Guo S, Lin J, Lin J. Microstructure, mechanical property and metal release of As-SLM CoCrW alloy under different solution treatment conditions. J Mech Behav Biomed Mater 2015; 55:179-190. [PMID: 26590910 DOI: 10.1016/j.jmbbm.2015.10.019] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2015] [Revised: 10/20/2015] [Accepted: 10/23/2015] [Indexed: 11/26/2022]
Abstract
In the study, the microstructure, mechanical property and metal release behavior of selective laser melted CoCrW alloys under different solution treatment conditions were systemically investigated to assess their potential use in orthopedic implants. The effects of the solution treatment on the microstructure, mechanical properties and metal release were systematically studied by OM, SEM, XRD, tensile test, and ICP-AES, respectively. The XRD indicated that during the solution treatment the alloy underwent the transformation of γ-fcc to ε-hcp phase; the ε-hcp phase nearly dominated in the alloy when treated at 1200°C following the water quenching; the results from OM, SEM showed that the microstructural change was occurred under different solution treatments; solution at 1150°C with furnace cooling contributed to the formation of larger precipitates at the grain boundary regions, while the size and number of the precipitates was decreased as heated above 1100°C with the water quenching; moreover, the diamond-like structure was invisible at higher solution temperature over 1150°C following water quenching; compared with the furnace cooling, the alloy quenched by water showed excellent mechanical properties and low amount of metal release; as the alloy heated at 1200°C, the mechanical properties of the alloy reached their optimum combination at UTS=1113.6MPa, 0.2%YS=639.5MPa, and E%=20.1%, whilst showed the lower total quantity of metal release. It is suggested that a proper solution treatment is an efficient strategy for improving the mechanical properties and corrosion resistance of As-SLM CoCrW alloy that show acceptable tensile ductility.
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Affiliation(s)
- Yanjin Lu
- Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, China
| | - Songquan Wu
- Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, China
| | - Yiliang Gan
- Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, China
| | - Shuyuan Zhang
- Institute of Metal Research, Chinese Academy of Sciences, China
| | - Sai Guo
- Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, China
| | - Junjie Lin
- Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, China
| | - Jinxin Lin
- Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, China.
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Yamanaka K, Mori M, Chiba A. Assessment of precipitation behavior in dental castings of a Co–Cr–Mo alloy. J Mech Behav Biomed Mater 2015; 50:268-76. [DOI: 10.1016/j.jmbbm.2015.06.020] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Revised: 06/17/2015] [Accepted: 06/19/2015] [Indexed: 11/27/2022]
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29
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Mori M, Yamanaka K, Kuramoto K, Ohmura K, Ashino T, Chiba A. Effect of carbon on the microstructure, mechanical properties and metal ion release of Ni-free Co–Cr–Mo alloys containing nitrogen. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2015; 55:145-54. [DOI: 10.1016/j.msec.2015.05.058] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2014] [Revised: 11/28/2014] [Accepted: 05/18/2015] [Indexed: 10/23/2022]
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30
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Qiu KJ, Liu Y, Zhou FY, Wang BL, Li L, Zheng YF, Liu YH. Microstructure, mechanical properties, castability and in vitro biocompatibility of Ti-Bi alloys developed for dental applications. Acta Biomater 2015; 15:254-65. [PMID: 25595472 DOI: 10.1016/j.actbio.2015.01.009] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2014] [Revised: 12/19/2014] [Accepted: 01/02/2015] [Indexed: 12/30/2022]
Abstract
In this study, the microstructure, mechanical properties, castability, electrochemical behaviors, cytotoxicity and hemocompatibility of Ti-Bi alloys with pure Ti as control were systematically investigated to assess their potential applications in the dental field. The experimental results showed that, except for the Ti-20Bi alloy, the microstructure of all other Ti-Bi alloys exhibit single α-Ti phase, while Ti-20Bi alloy is consisted of mainly α-Ti phase and a small amount of BiTi2 and BiTi3 phases. The tensile strength, hardness and wear resistance of Ti-Bi alloys were demonstrated to be improved monotonically with the increase of Bi content. The castability test showed that Ti-2Bi alloy increased the castability of pure Ti by 11.7%. The studied Ti-Bi alloys showed better corrosion resistance than pure Ti in both AS (artificial saliva) and ASFL (AS containing 0.2% NaF and 0.3% lactic acid) solutions. The concentrations of both Ti ion and Bi ion released from Ti-Bi alloys are extremely low in AS, ASF (AS containing 0.2% NaF) and ASL (AS containing 0.3% lactic acid) solutions. However, in ASFL solution, a large number of Ti and Bi ions are released. In addition, Ti-Bi alloys produced no significant deleterious effect to L929 cells and MG63 cells, similar to pure Ti, indicating a good in vitro biocompatibility. Besides, both L929 and MG63 cells perform excellent cell adhesion ability on Ti-Bi alloys. The hemolysis test exhibited that Ti-Bi alloys have an ultra-low hemolysis percentage below 1% and are considered nonhemolytic. To sum up, the Ti-2Bi alloy exhibits the optimal comprehensive performance and has great potential for dental applications.
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Affiliation(s)
- K J Qiu
- Center for Biomedical Materials and Engineering, Harbin Engineering University, Harbin 150001, China
| | - Y Liu
- Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871, China
| | - F Y Zhou
- Center for Biomedical Materials and Engineering, Harbin Engineering University, Harbin 150001, China
| | - B L Wang
- Center for Biomedical Materials and Engineering, Harbin Engineering University, Harbin 150001, China
| | - L Li
- Center for Biomedical Materials and Engineering, Harbin Engineering University, Harbin 150001, China
| | - Y F Zheng
- Center for Biomedical Materials and Engineering, Harbin Engineering University, Harbin 150001, China; Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871, China.
| | - Y H Liu
- General Dental Department, School of Stomatology, Peking University, Beijing 100081, China
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Lu Y, Wu S, Gan Y, Li J, Zhao C, Zhuo D, Lin J. Investigation on the microstructure, mechanical property and corrosion behavior of the selective laser melted CoCrW alloy for dental application. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2015; 49:517-525. [PMID: 25686979 DOI: 10.1016/j.msec.2015.01.023] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Revised: 01/04/2015] [Accepted: 01/06/2015] [Indexed: 11/25/2022]
Abstract
In this study, an experimental investigation on fabricating Ni-free CoCrW alloys by selective laser melting (SLM) for dental application was conducted in terms of microstructure, hardness, mechanical property, electrochemical behavior, and metal release; and line and island scanning strategy were applied to determine whether these strategies are able to obtain expected CoCrW parts. The XRD revealed that the γ-phase and ε-phase coexisted in the as-SLM CoCrW alloys; The OM and SEM images showed that the microstructure of CoCrW alloys appeared square-like pattern with the fine cellular dendrites at the borders; tensile test suggested that the difference of mechanical properties of line- and island-formed specimens was very small; whilst the outcomes from the electrochemical and metal release tests indicated that the island-formed alloys showed slightly better corrosion resistance than line-formed ones in PBS and Hanks solutions. Considering that the mechanical properties and corrosion resistance of line-formed and island-formed specimens meet the standards of ISO 22674:2006 and EN ISO 10271, CoCrW dental alloys can be successfully fabricated by line and island scanning strategies in the SLM process.
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Affiliation(s)
- Yanjin Lu
- Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, 155 Yangqiao Road West, Fuzhou, China
| | - Songquan Wu
- Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, 155 Yangqiao Road West, Fuzhou, China
| | - Yiliang Gan
- Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, 155 Yangqiao Road West, Fuzhou, China
| | - Junlei Li
- Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang, China
| | - Chaoqian Zhao
- Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, 155 Yangqiao Road West, Fuzhou, China; College Materials Science and Engineering, Fujian Normal University, Fuzhou, China
| | - Dongxian Zhuo
- Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, 155 Yangqiao Road West, Fuzhou, China
| | - Jinxin Lin
- Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, 155 Yangqiao Road West, Fuzhou, China.
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Proença L, Barroso H, Figueiredo N, Lino AR, Capelo S, Fonseca ITE. The corrosion resistance of Wiron(®)88 in the presence of S. mutans and S. sobrinus bacteria. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2015; 26:5353. [PMID: 25578707 DOI: 10.1007/s10856-014-5353-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Accepted: 07/06/2014] [Indexed: 06/04/2023]
Abstract
The corrosion resistance of Wiron(®)88, a Ni-Cr-Mo alloy, was evaluated in liquid growth media in the absence and presence of the Streptococcus sobrinus and Streptococcus mutans strains. Open circuit potential measurements, cyclic voltammetry, linear sweep voltammetry, as well as electronic microscopy coupled to electron diffraction spectroscopy (SEM/EDS), were the main techniques used in this study. It was concluded that the presence of S. sobrinus and S. mutans have only a slight effect on the corrosion resistance of the Wiron(®)88 alloy, with the S. mutans being slightly more aggressive. For both strains the corrosion resistance R p is of the same order (kΩ cm(2)). After 24 h immersion the S. sobrinus lead to and R p of 11.02, while the S. mutans lead to of 5.59 kΩ cm(2). SEM/EDS studies on the Wiron(®)88 samples, with 24 days of immersion, at 37 °C, have confirmed bio-corrosion of the alloy occurring through the dissolution of Ni as Ni(2+) and formation of chromium and molybdenum oxides. The bacterial adhesion to the surface is not uniform.
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Affiliation(s)
- L Proença
- CCMM, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, Ed. C8, 1749-016, Lisbon, Portugal
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Influence of carbon addition on mechanical properties and microstructures of Ni-free Co–Cr–W alloys subjected to thermomechanical processing. J Mech Behav Biomed Mater 2014; 37:274-85. [DOI: 10.1016/j.jmbbm.2014.05.025] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2013] [Revised: 05/19/2014] [Accepted: 05/28/2014] [Indexed: 11/21/2022]
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Al Jabbari Y, Koutsoukis T, Barmpagadaki X, Zinelis S. Metallurgical and interfacial characterization of PFM Co–Cr dental alloys fabricated via casting, milling or selective laser melting. Dent Mater 2014; 30:e79-88. [DOI: 10.1016/j.dental.2014.01.008] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Revised: 09/25/2013] [Accepted: 01/16/2014] [Indexed: 10/25/2022]
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35
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Ti–Ga binary alloys developed as potential dental materials. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2014; 34:474-83. [DOI: 10.1016/j.msec.2013.10.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Revised: 09/26/2013] [Accepted: 10/01/2013] [Indexed: 11/20/2022]
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36
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Yamanaka K, Mori M, Chiba A. Effects of nitrogen addition on microstructure and mechanical behavior of biomedical Co–Cr–Mo alloys. J Mech Behav Biomed Mater 2014; 29:417-26. [DOI: 10.1016/j.jmbbm.2013.10.006] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Revised: 09/28/2013] [Accepted: 10/07/2013] [Indexed: 11/28/2022]
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37
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Microstructures and mechanical properties of Co–29Cr–6Mo alloy fabricated by selective laser melting process for dental applications. J Mech Behav Biomed Mater 2013; 21:67-76. [DOI: 10.1016/j.jmbbm.2013.01.021] [Citation(s) in RCA: 314] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Revised: 01/21/2013] [Accepted: 01/26/2013] [Indexed: 11/23/2022]
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