1
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An D, Xiao Y, Yu J, Zhang X, Li Z, Ma Y, Li R, Han X, Li X, Chen J, Zaefferer S. The Role of Dislocation Type in the Thermal Stability of Cellular Structures in Additively Manufactured Austenitic Stainless Steel. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2402962. [PMID: 38951958 PMCID: PMC11434014 DOI: 10.1002/advs.202402962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Indexed: 07/03/2024]
Abstract
The ultrafine cellular structure promotes the extraordinary mechanical performance of metals manufactured by laser powder-bed-fusion (L-PBF). An in-depth understanding of the mechanisms governing the thermal stability of such structures is crucial for designing reliable L-PBF components for high-temperature applications. Here, characterizations and 3D discrete dislocation dynamics simulations are performed to comprehensively understand the evolution of cellular structures in 316L stainless steel during annealing. The dominance of screw-type dislocation dipoles in the dislocation cells is reported. However, the majority of dislocations in sub-grain boundaries (SGBs) are geometrically necessary dislocations (GNDs) with varying types. The disparity in dislocation types can be attributed to the variation in local stacking fault energy (SFE) arising from chemical heterogeneity. The presence of screw-type dislocations facilitates the unpinning of dislocations from dislocation cells/SGBs, resulting in a high dislocation mobility. In contrast, the migration of SGBs with dominating edge-type GNDs requires collaborative motion of dislocations, leading to a sluggish migration rate and an enhanced thermal stability. This work emphasizes the significant role of dislocation type in the thermal stability of cellular structures. Furthermore, it sheds light on how to locally tune dislocation structures with desired dislocation types by adjusting local chemistry-dependent SFE and heat treatment.
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Affiliation(s)
- Dayong An
- Department of Plasticity TechnologySchool of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai200030P. R. China
| | - Yao Xiao
- Institute of Clean EnergyYangtze River Delta Research InstituteNorthwestern Polytechnical UniversityTaicang215400P. R. China
| | - Junshi Yu
- Applied Mechanics and Structure Safety Laboratory of Sichuan ProvinceSchool of Mechanics and Aerospace EngineeringSouthwest Jiaotong UniversityChengdu610031P. R. China
| | - Xu Zhang
- Applied Mechanics and Structure Safety Laboratory of Sichuan ProvinceSchool of Mechanics and Aerospace EngineeringSouthwest Jiaotong UniversityChengdu610031P. R. China
| | - Zan Li
- State Key Laboratory of Metal Matrix CompositesShanghai Jiao Tong UniversityShanghai200240P. R. China
| | - Yan Ma
- Max‐Planck‐Institut für Eisenforschung40237DüsseldorfGermany
| | - Rui Li
- Institute of Clean EnergyYangtze River Delta Research InstituteNorthwestern Polytechnical UniversityTaicang215400P. R. China
| | - Xianhong Han
- Department of Plasticity TechnologySchool of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai200030P. R. China
| | - Xifeng Li
- Department of Plasticity TechnologySchool of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai200030P. R. China
| | - Jun Chen
- Department of Plasticity TechnologySchool of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai200030P. R. China
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2
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Borhani MR, Rajabi M, Shoja Razavi R, Jamaati R. Investigating the relationship between mechanical properties and residual stress in the laser cladding process of Inconel 625 superalloy. Heliyon 2023; 9:e19791. [PMID: 37809515 PMCID: PMC10559123 DOI: 10.1016/j.heliyon.2023.e19791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 08/31/2023] [Accepted: 08/31/2023] [Indexed: 10/10/2023] Open
Abstract
In the present study, the tensile strength, fracture surface, hardness, and amount of residual stress in Inconel 625 super alloy cladded with direct metal deposition (DLD) process in the states before and after stress relief was studied. Residual stresses on the cladding layer surface were determined via XRD method. According to results, the yield strength of Am sample increased by 10% compared to thecast sample (reference sample). Although the yield strength experiebced an increase, the ductility followed an opposite trend falling from 42.5% to 26%. According to residual stress test outcomes, tensile residual stress of 361 MPa in the additive-manufactured sample. After stress relaxation heat treatment and almost complete removal of residual stress, the ductility reached 52.5%, the ultimate strength was also improved by 17% from cast sample. Also, after stress relaxation, the hardness of the sample and its fluctuations are reduced.
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Affiliation(s)
- Mohammad Reza Borhani
- Department of Materials Engineering, Babol Noshirvani University of Technology, Babol, 47148-71167, Iran
| | - Mohammad Rajabi
- Department of Materials Engineering, Babol Noshirvani University of Technology, Babol, 47148-71167, Iran
| | - Reza Shoja Razavi
- Faculty of Materials & Manufacturing Technologies, Malek Ashtar University of Technology, Iran
| | - Roohollah Jamaati
- Department of Materials Engineering, Babol Noshirvani University of Technology, Babol, 47148-71167, Iran
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3
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Plotkowski A, Saleeby K, Fancher CM, Haley J, Madireddy G, An K, Kannan R, Feldhausen T, Lee Y, Yu D, Leach C, Vaughan J, Babu SS. Operando neutron diffraction reveals mechanisms for controlled strain evolution in 3D printing. Nat Commun 2023; 14:4950. [PMID: 37587109 PMCID: PMC10432395 DOI: 10.1038/s41467-023-40456-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Accepted: 07/28/2023] [Indexed: 08/18/2023] Open
Abstract
Residual stresses affect the performance and reliability of most manufactured goods and are prevalent in casting, welding, and additive manufacturing (AM, 3D printing). Residual stresses are associated with plastic strain gradients accrued due to transient thermal stress. Complex thermal conditions in AM produce similarly complex residual stress patterns. However, measuring real-time effects of processing on stress evolution is not possible with conventional techniques. Here we use operando neutron diffraction to characterize transient phase transformations and lattice strain evolution during AM of a low-temperature transformation steel. Combining diffraction, infrared and simulation data reveals that elastic and plastic strain distributions are controlled by motion of the face-centered cubic and body-centered cubic phase boundary. Our results provide a new pathway to design residual stress states and property distributions within additively manufactured components. These findings will enable control of residual stress distributions for advantages such as improved fatigue life or resistance to stress-corrosion cracking.
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Affiliation(s)
- A Plotkowski
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.
| | - K Saleeby
- Manufacturing Science Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - C M Fancher
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - J Haley
- Electrification and Energy Infrastructure Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - G Madireddy
- Manufacturing Science Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - K An
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - R Kannan
- Manufacturing Science Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - T Feldhausen
- Manufacturing Science Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Y Lee
- Computational Sciences and Engineering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - D Yu
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - C Leach
- Electrification and Energy Infrastructure Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - J Vaughan
- Manufacturing Science Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - S S Babu
- Manufacturing Science Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
- Department of Mechanical, Aerospace, and Biomedical Engineering, The University of Tennessee - Knoxville, Knoxville, TN, 37996, USA
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4
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Li W, Yao H, Ding Z, Zhou Y, Wei P, Yue J, Su W, Zhu W. Cavitation Erosion Prevention Using Laser Shock Peening: Development of a Predictive Evaluation System. MATERIALS (BASEL, SWITZERLAND) 2023; 16:5096. [PMID: 37512368 PMCID: PMC10383491 DOI: 10.3390/ma16145096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2023] [Revised: 07/15/2023] [Accepted: 07/17/2023] [Indexed: 07/30/2023]
Abstract
Marine flow-passing components are susceptible to cavitation erosion (CE), and researchers have worked to find ways to reduce its effects. Laser Shock Peening (LSP), a material strengthening method, has been widely used in aerospace and other cutting-edge fields. In recent years, LSP has been used in cavitation resistance research. However, the current LSP research does not realize a comprehensive predictive assessment of the material's CE resistance. This paper uses m stresses to develop a comprehensive set of strengthening effect prediction models from LSP to CE using finite element analysis (FEA). Results show that the LSP-1 sample (4 mm spot, 10 J energy) introduced a compressive residual stress value of 37.4 MPa, better than that of 16.6 MPa with the LSP-2 sample (6 mm spot, 10 J energy), which is generally consistent with the experimental findings; the model predicts a 16.35% improvement in the resistance of LSP-1 sample to water jet damage, which is comparable to the experimental result of 14.02%; additionally, interactions between micro-jets do not predominate the cavitation erosion process and the final CE effect of the material is mainly due to the accumulation of jet-material interaction.
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Affiliation(s)
- Wenlong Li
- College of Science, Hohai University, Nanjing 211100, China
| | - Hongbing Yao
- College of Science, Hohai University, Nanjing 211100, China
| | - Zhipeng Ding
- College of Science, Hohai University, Nanjing 211100, China
| | - Yuanhang Zhou
- College of Science, Hohai University, Nanjing 211100, China
| | - Pengyu Wei
- China Ship Scientific Research Center, Wuxi 214082, China
| | - Jiang Yue
- College of Science, Hohai University, Nanjing 211100, China
| | - Wei Su
- College of Science, Hohai University, Nanjing 211100, China
| | - Weihua Zhu
- College of Science, Hohai University, Nanjing 211100, China
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5
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Akwaboa S, Zeng C, Amoafo-Yeboah N, Ibekwe S, Mensah P. Thermophysical Properties of Laser Powder Bed Fused Ti-6Al-4V and AlSi10Mg Alloys Made with Varying Laser Parameters. MATERIALS (BASEL, SWITZERLAND) 2023; 16:4920. [PMID: 37512194 PMCID: PMC10381728 DOI: 10.3390/ma16144920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2023] [Revised: 07/05/2023] [Accepted: 07/07/2023] [Indexed: 07/30/2023]
Abstract
This study investigated the influence of diverse laser processing parameters on the thermophysical properties of Ti-6Al-4V and AlSi10Mg alloys manufactured via laser powder bed fusion. During fabrication, the laser power (50 W, 75 W, 100 W) and laser scanning speed (0.2 m/s, 0.4 m/s, 0.6 m/s) were adjusted while keeping other processing parameters constant. Besides laser processing parameters, this study also explored the impact of test temperatures on the thermophysical properties of the alloys. It was found that the thermophysical properties of L-PBF Ti-6Al-4V alloy samples were sensitive to laser processing parameters, while L-PBF AlSi10Mg alloy showed less sensitivity. In general, for the L-PBF Ti-6Al-4V alloy, as the laser power increased and laser scan speed decreased, both thermal diffusivity and conductivity increased. Both L-PBF Ti-6Al-4V and L-PBF AlSi10Mg alloys demonstrated similar dependence on test temperatures, with thermal diffusivity and conductivity increasing as the test temperature rose. The CALPHAD software Thermo-Calc (2023b), applied in Scheil Solidification Mode, was utilized to calculate the quantity of solution atoms, thus enhancing our understanding of observed thermal conductivity variations. A detailed analysis revealed how variations in laser processing parameters and test temperatures significantly influence the alloy's resulting density, specific heat, thermal diffusivity, and thermal conductivity. This research not only highlights the importance of processing parameters but also enriches comprehension of the mechanisms influencing these effects in the domain of laser powder bed fusion.
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Affiliation(s)
- Stephen Akwaboa
- Department of Mechanical Engineering, Southern University and A&M College, Baton Rouge, LA 70807, USA
| | - Congyuan Zeng
- Department of Mechanical Engineering, Southern University and A&M College, Baton Rouge, LA 70807, USA
| | - Nigel Amoafo-Yeboah
- Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC 27695, USA
| | - Samuel Ibekwe
- Department of Mechanical Engineering, Southern University and A&M College, Baton Rouge, LA 70807, USA
| | - Patrick Mensah
- Department of Mechanical Engineering, Southern University and A&M College, Baton Rouge, LA 70807, USA
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6
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Wang H, Tong R, Liu G, Sha A, Song L, Zhang T. In-Situ Synchrotron HEXRD Study on the Micro-Stress Evolution Behavior of a Superalloy during Room-Temperature Compression. MATERIALS (BASEL, SWITZERLAND) 2023; 16:ma16103761. [PMID: 37241383 DOI: 10.3390/ma16103761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Revised: 05/08/2023] [Accepted: 05/15/2023] [Indexed: 05/28/2023]
Abstract
The residual stress generated during heat treatment of nickel-base superalloys will affect their service performance and introduce primary cracks. In a component with high residual stress, a tiny amount of plastic deformation at room temperature can release the stress to a certain extent. However, the stress-releasing mechanism is still unclear. In the present study, the micro-mechanical behavior of the FGH96 nickel-base superalloy during room temperature compression was studied using in situ synchrotron radiation high-energy X-ray diffraction. The in situ evolution of the lattice strain was observed during deformation. The stress distribution mechanism of grains and phases with different orientations was clarified. The results show that at the elastic deformation stage, the (200) lattice plane of γ' phase bears more stress after the stress reaches 900 MPa. When the stress exceeds 1160 MPa, the load is redistributed to the grains with their <200> crystal directions aligned with the loading direction. After yielding, the γ' phase still bears the main stress.
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Affiliation(s)
- Hao Wang
- Beijing Institute of Aeronautical Materials, AECC, Beijing 100095, China
| | - Ruolan Tong
- State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an 710072, China
| | - Guangxu Liu
- Beijing Institute of Aeronautical Materials, AECC, Beijing 100095, China
| | - Aixue Sha
- Beijing Institute of Aeronautical Materials, AECC, Beijing 100095, China
| | - Lin Song
- State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an 710072, China
| | - Tiebang Zhang
- State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an 710072, China
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7
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Smith TM, Kantzos CA, Zarkevich NA, Harder BJ, Heczko M, Gradl PR, Thompson AC, Mills MJ, Gabb TP, Lawson JW. A 3D printable alloy designed for extreme environments. Nature 2023; 617:513-518. [PMID: 37076622 PMCID: PMC10191839 DOI: 10.1038/s41586-023-05893-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Accepted: 02/27/2023] [Indexed: 04/21/2023]
Abstract
Multiprincipal-element alloys are an enabling class of materials owing to their impressive mechanical and oxidation-resistant properties, especially in extreme environments1,2. Here we develop a new oxide-dispersion-strengthened NiCoCr-based alloy using a model-driven alloy design approach and laser-based additive manufacturing. This oxide-dispersion-strengthened alloy, called GRX-810, uses laser powder bed fusion to disperse nanoscale Y2O3 particles throughout the microstructure without the use of resource-intensive processing steps such as mechanical or in situ alloying3,4. We show the successful incorporation and dispersion of nanoscale oxides throughout the GRX-810 build volume via high-resolution characterization of its microstructure. The mechanical results of GRX-810 show a twofold improvement in strength, over 1,000-fold better creep performance and twofold improvement in oxidation resistance compared with the traditional polycrystalline wrought Ni-based alloys used extensively in additive manufacturing at 1,093 °C5,6. The success of this alloy highlights how model-driven alloy designs can provide superior compositions using far fewer resources compared with the 'trial-and-error' methods of the past. These results showcase how future alloy development that leverages dispersion strengthening combined with additive manufacturing processing can accelerate the discovery of revolutionary materials.
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Affiliation(s)
| | | | | | | | - Milan Heczko
- Department of Materials Science and Engineering, The Ohio State University, Columbus, OH, USA
| | - Paul R Gradl
- Propulsion Department, NASA Marshall Space Flight Center, Huntsville, AL, USA
| | | | - Michael J Mills
- Department of Materials Science and Engineering, The Ohio State University, Columbus, OH, USA
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8
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Richter J, Bartzsch G, Scherbring S, Bolender A, Vollmer M, Mola J, Volkova O, Niendorf T. Metastable CrMnNi steels processed by laser powder bed fusion: experimental assessment of elementary mechanisms contributing to microstructure, properties and residual stress. Sci Rep 2022; 12:21862. [PMID: 36529751 PMCID: PMC9760645 DOI: 10.1038/s41598-022-26052-x] [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: 08/13/2022] [Accepted: 12/08/2022] [Indexed: 12/23/2022] Open
Abstract
The complex thermal history imposed by the laser-based powder bed fusion of metals (PBF-LB/M) process is known to promote the evolution of unique microstructures. In the present study, metastable CrMnNi steels with different nickel contents and, thus, different phase stabilities are manufactured by PBF-LB/M. Results clearly reveal that an adequate choice of materials will allow to tailor mechanical properties as well as residual stress states in the as-built material to eventually redundantize any thermal post-treatment. The chemical differences lead to different phase constitutions in as-built conditions and, thus, affect microstructure evolution and elementary deformation mechanisms upon deformation, i.e., twinning and martensitic transformation. Such alloys designed for additive manufacturing (AM) highlight the possibility to tackle well-known challenges in AM such as limited damage tolerance, porosity and detrimental residual stress states without conducting any post treatments, e.g., stress relieve and hot isostatic pressing. From the perspective of robust design of AM components, indeed it seems to be a very effective approach to adapt the material to the process characteristics of AM.
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Affiliation(s)
- J. Richter
- grid.5155.40000 0001 1089 1036Institute of Materials Engineering – Metallic Materials, University of Kassel, Moenchebergstrasse 3, 34125 Kassel, Germany
| | - G. Bartzsch
- grid.6862.a0000 0001 0805 5610Institute of Iron and Steel Technology, TU Bergakademie Freiberg, Leipziger Strasse 34, 09599 Freiberg/Saxony, Germany
| | - S. Scherbring
- grid.10854.380000 0001 0672 4366Faculty of Engineering and Computer Sciences, Materials Design and Structural Integrity Laboratory, Osnabrueck University of Applied Sciences, Albrechtstrasse 30, 49076 Osnabrueck, Germany
| | - A. Bolender
- grid.5155.40000 0001 1089 1036Institute of Materials Engineering – Metallic Materials, University of Kassel, Moenchebergstrasse 3, 34125 Kassel, Germany
| | - M. Vollmer
- grid.5155.40000 0001 1089 1036Institute of Materials Engineering – Metallic Materials, University of Kassel, Moenchebergstrasse 3, 34125 Kassel, Germany
| | - J. Mola
- grid.10854.380000 0001 0672 4366Faculty of Engineering and Computer Sciences, Materials Design and Structural Integrity Laboratory, Osnabrueck University of Applied Sciences, Albrechtstrasse 30, 49076 Osnabrueck, Germany
| | - O. Volkova
- grid.6862.a0000 0001 0805 5610Institute of Iron and Steel Technology, TU Bergakademie Freiberg, Leipziger Strasse 34, 09599 Freiberg/Saxony, Germany
| | - T. Niendorf
- grid.5155.40000 0001 1089 1036Institute of Materials Engineering – Metallic Materials, University of Kassel, Moenchebergstrasse 3, 34125 Kassel, Germany
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9
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Zhu Y, Zhang K, Meng Z, Zhang K, Hodgson P, Birbilis N, Weyland M, Fraser HL, Lim SCV, Peng H, Yang R, Wang H, Huang A. Ultrastrong nanotwinned titanium alloys through additive manufacturing. NATURE MATERIALS 2022; 21:1258-1262. [PMID: 36109672 DOI: 10.1038/s41563-022-01359-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Accepted: 08/09/2022] [Indexed: 05/25/2023]
Abstract
Titanium alloys, widely used in the aerospace, automotive and energy sectors, require complex casting and thermomechanical processing to achieve the high strengths required for load-bearing applications. Here we reveal that additive manufacturing can exploit thermal cycling and rapid solidification to create ultrastrong and thermally stable titanium alloys, which may be directly implemented in service. As demonstrated in a commercial titanium alloy, after simple post-heat treatment, adequate elongation and tensile strengths over 1,600 MPa are achieved. The excellent properties are attributed to the unusual formation of dense, stable and internally twinned nanoprecipitates, which are rarely observed in traditionally processed titanium alloys. These nanotwinned precipitates are shown to originate from a high density of dislocations with a dominant screw character and formed from the additive manufacturing process. The work here paves the way to fabricate structural materials with unique microstructures and excellent properties for broad applications.
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Affiliation(s)
- Yuman Zhu
- Monash Centre for Additive Manufacturing, Monash University, Notting Hill, Victoria, Australia.
- Department of Material Science and Engineering, Monash University, Clayton, Victoria, Australia.
| | - Kun Zhang
- Monash Centre for Additive Manufacturing, Monash University, Notting Hill, Victoria, Australia
- Department of Material Science and Engineering, Monash University, Clayton, Victoria, Australia
| | - Zhichao Meng
- Institute of Metal Research, Chinese Academy of Sciences, Shenyang, China
| | - Kai Zhang
- Monash Centre for Additive Manufacturing, Monash University, Notting Hill, Victoria, Australia
- School of Materials Science and Engineering, University of Shanghai for Science and Technology, Shanghai, China
| | - Peter Hodgson
- Institute for Frontier Materials, Deakin University, Geelong, Victoria, Australia
| | - Nick Birbilis
- College of Engineering and Computer Science, Australian National University, Canberra, Australian Capital Territory, Australia
| | - Matthew Weyland
- Department of Material Science and Engineering, Monash University, Clayton, Victoria, Australia
- Monash Centre for Electron Microscopy, Monash University, Clayton, Victoria, Australia
| | - Hamish L Fraser
- Center for the Accelerated Maturation of Materials, Department of Materials Science and Engineering, The Ohio State University, Columbus, OH, USA
| | - Samuel Chao Voon Lim
- Monash Centre for Additive Manufacturing, Monash University, Notting Hill, Victoria, Australia
- Department of Material Science and Engineering, Monash University, Clayton, Victoria, Australia
| | - Huizhi Peng
- Monash Centre for Additive Manufacturing, Monash University, Notting Hill, Victoria, Australia
- Department of Material Science and Engineering, Monash University, Clayton, Victoria, Australia
| | - Rui Yang
- Institute of Metal Research, Chinese Academy of Sciences, Shenyang, China
- Centre for Adaptative System Engineering, School of Creativity and Arts, ShanghaiTech University, Shanghai, China
| | - Hao Wang
- School of Materials Science and Engineering, University of Shanghai for Science and Technology, Shanghai, China.
| | - Aijun Huang
- Monash Centre for Additive Manufacturing, Monash University, Notting Hill, Victoria, Australia.
- Department of Material Science and Engineering, Monash University, Clayton, Victoria, Australia.
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10
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Multiscale hierarchical and heterogeneous mechanical response of additively manufactured novel Al alloy investigated by high-resolution nanoindentation mapping. Sci Rep 2022; 12:18344. [PMID: 36316407 PMCID: PMC9622702 DOI: 10.1038/s41598-022-23083-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 10/25/2022] [Indexed: 11/05/2022] Open
Abstract
Smart alloying and microstructural engineering mitigate challenges associated with laser-powder bed fusion additive manufacturing (L-PBFAM). A novel Al–Ni–Ti–Zr alloy utilized grain refinement by heterogeneous nucleation and eutectic solidification to achieve superior performance-printability synergy. Conventional mechanical testing cannot delineate complex micromechanics of such alloys. This study combined multiscale nanomechanical and microstructural mapping to illustrate mechanical signatures associated with hierarchical heat distribution and rapid solidification of L-PBFAM. The disproportionate hardening effect imparted by Al3(Ti,Zr) precipitates in the pool boundaries and the semi-solid zone was successfully demonstrated. Nanomechanical response associated with heterogeneity in particle volume fraction and coherency across melt pool was interpreted from nanoindentation force–displacement curves. The hardness map effectively delineated the weakest and strongest sections in the pool with microscopic accuracy. The presented approach serves as a high throughput methodology to establish the chemistry-processing-microstructure-properties correlation of newly designed alloys for L-PBFAM.
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11
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Strong yet ductile nanolamellar high-entropy alloys by additive manufacturing. Nature 2022; 608:62-68. [PMID: 35922499 DOI: 10.1038/s41586-022-04914-8] [Citation(s) in RCA: 38] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 05/27/2022] [Indexed: 11/09/2022]
Abstract
Additive manufacturing produces net-shaped components layer by layer for engineering applications1-7. The additive manufacture of metal alloys by laser powder bed fusion (L-PBF) involves large temperature gradients and rapid cooling2,6, which enables microstructural refinement at the nanoscale to achieve high strength. However, high-strength nanostructured alloys produced by laser additive manufacturing often have limited ductility3. Here we use L-PBF to print dual-phase nanolamellar high-entropy alloys (HEAs) of AlCoCrFeNi2.1 that exhibit a combination of a high yield strength of about 1.3 gigapascals and a large uniform elongation of about 14 per cent, which surpasses those of other state-of-the-art additively manufactured metal alloys. The high yield strength stems from the strong strengthening effects of the dual-phase structures that consist of alternating face-centred cubic and body-centred cubic nanolamellae; the body-centred cubic nanolamellae exhibit higher strengths and higher hardening rates than the face-centred cubic nanolamellae. The large tensile ductility arises owing to the high work-hardening capability of the as-printed hierarchical microstructures in the form of dual-phase nanolamellae embedded in microscale eutectic colonies, which have nearly random orientations to promote isotropic mechanical properties. The mechanistic insights into the deformation behaviour of additively manufactured HEAs have broad implications for the development of hierarchical, dual- and multi-phase, nanostructured alloys with exceptional mechanical properties.
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12
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Pan L, Li S, Cao J, Wu J, Zhang Z, Wang K, Huang Q, Ma B, Li W, Wang Z. Ultrafast Time-Resolved Pump-Probe Investigation of Nanosecond Extreme Ultraviolet-Light-Induced Damage Dynamics on B 4C/Ru Nano-Bilayer Film. NANO LETTERS 2022; 22:5260-5268. [PMID: 35759364 DOI: 10.1021/acs.nanolett.2c01171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
An ultrafast time-resolved pump-probe setup with both high temporal and spatial resolution is developed to investigate the transient interaction between a nanosecond extreme ultraviolet (EUV) pulse and matter. By using a delayed femtosecond probe pulse, the pattern evolution of surface modification induced by an EUV pump at a wavelength of 13.5 nm can be imaged at different delay times, which provides deep insight into the EUV-induced damage dynamics and damage mechanisms. As a demonstration, single-shot EUV damage on a B4C(6.0 nm)/Ru(30.4 nm)/D263 nano-bilayer optical film is studied using this pump-probe method. A recoverable phenomenon is found during the evolution process of the dome-shaped damage region. This is explained by the elastic and plastic deformations resulting from the huge compressive stress difference at the Ru-substrate interface with the help of simulations on the thermal effects and mechanical responses. This damage mechanism is further proven by the complementary experiments at a higher EUV fluence at 13.5 nm.
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Affiliation(s)
- Liuyang Pan
- MOE Key Laboratory of Advanced Micro-Structured Materials, Shanghai 200092, China
- Institute of Precision Optical Engineering, School of Physics Science and Engineering, Tongji University, Shanghai 200092, China
| | - Shuhui Li
- MOE Key Laboratory of Advanced Micro-Structured Materials, Shanghai 200092, China
- Institute of Precision Optical Engineering, School of Physics Science and Engineering, Tongji University, Shanghai 200092, China
| | - Jinyu Cao
- MOE Key Laboratory of Advanced Micro-Structured Materials, Shanghai 200092, China
- Institute of Precision Optical Engineering, School of Physics Science and Engineering, Tongji University, Shanghai 200092, China
| | - Jiali Wu
- MOE Key Laboratory of Advanced Micro-Structured Materials, Shanghai 200092, China
- Institute of Precision Optical Engineering, School of Physics Science and Engineering, Tongji University, Shanghai 200092, China
| | - Zhe Zhang
- MOE Key Laboratory of Advanced Micro-Structured Materials, Shanghai 200092, China
- Institute of Precision Optical Engineering, School of Physics Science and Engineering, Tongji University, Shanghai 200092, China
| | - Kun Wang
- School of Mechanical Engineering, Tongji University, Shanghai 200092, China
| | - Qiushi Huang
- MOE Key Laboratory of Advanced Micro-Structured Materials, Shanghai 200092, China
- Institute of Precision Optical Engineering, School of Physics Science and Engineering, Tongji University, Shanghai 200092, China
| | - Bin Ma
- MOE Key Laboratory of Advanced Micro-Structured Materials, Shanghai 200092, China
- Institute of Precision Optical Engineering, School of Physics Science and Engineering, Tongji University, Shanghai 200092, China
| | - Wenbin Li
- MOE Key Laboratory of Advanced Micro-Structured Materials, Shanghai 200092, China
- Institute of Precision Optical Engineering, School of Physics Science and Engineering, Tongji University, Shanghai 200092, China
| | - Zhanshan Wang
- MOE Key Laboratory of Advanced Micro-Structured Materials, Shanghai 200092, China
- Institute of Precision Optical Engineering, School of Physics Science and Engineering, Tongji University, Shanghai 200092, China
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13
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Understanding the Plastic Deformation of Gradient Interstitial Free (IF) Steel under Uniaxial Loading Using a Dislocation-Based Multiscale Approach. CRYSTALS 2022. [DOI: 10.3390/cryst12070889] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
Abstract
Gradient interstitial free (IF) steels have been shown to exhibit a superior combination of strength and ductility due to their multiscale microstructures. The novelty of the work resides in the implementation of a modified slip transmission and a back-stress quantity induced by a long-range dislocation interaction in the dislocation-based multiscale model. This is an improvement over the model we previously proposed. Simulations are performed on IF specimens with gradient structures and with homogeneous structures. The macroscopic behavior of the samples under tension and compression is studied. The evolution of the microstructure such as dislocations, geometrically necessary dislocations (GNDs), and the effects of grain orientation is analyzed. Results show that with our enhanced model, the simulations can successfully reproduce the stress-strain curves obtained experimentally on gradient nano IF steel specimens under tension. The simulations also capture the tension-compression asymmetry (TCA) in specimens with homogeneous and gradient microstructures. The initial texture is found to have a significant effect on the TCA of specimens with gradient microstructures.
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14
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Pinomaa T, Lindroos M, Jreidini P, Haapalehto M, Ammar K, Wang L, Forest S, Provatas N, Laukkanen A. Multiscale analysis of crystalline defect formation in rapid solidification of pure aluminium and aluminium-copper alloys. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2022; 380:20200319. [PMID: 34974728 PMCID: PMC8721336 DOI: 10.1098/rsta.2020.0319] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 09/01/2021] [Indexed: 06/14/2023]
Abstract
Rapid solidification leads to unique microstructural features, where a less studied topic is the formation of various crystalline defects, including high dislocation densities, as well as gradients and splitting of the crystalline orientation. As these defects critically affect the material's mechanical properties and performance features, it is important to understand the defect formation mechanisms, and how they depend on the solidification conditions and alloying. To illuminate the formation mechanisms of the rapid solidification induced crystalline defects, we conduct a multiscale modelling analysis consisting of bond-order potential-based molecular dynamics (MD), phase field crystal-based amplitude expansion simulations, and sequentially coupled phase field-crystal plasticity simulations. The resulting dislocation densities are quantified and compared to past experiments. The atomistic approaches (MD, PFC) can be used to calibrate continuum level crystal plasticity models, and the framework adds mechanistic insights arising from the multiscale analysis. This article is part of the theme issue 'Transport phenomena in complex systems (part 2)'.
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Affiliation(s)
- Tatu Pinomaa
- ICME group, VTT Technical Research Centre of Finland Ltd, Espoo, Finland
| | - Matti Lindroos
- ICME group, VTT Technical Research Centre of Finland Ltd, Espoo, Finland
| | - Paul Jreidini
- Department of Physics and Centre for the Physics of Materials, McGill University, Montreal, Canada
| | - Matias Haapalehto
- ICME group, VTT Technical Research Centre of Finland Ltd, Espoo, Finland
| | - Kais Ammar
- MINES ParisTech, PSL University, MAT - Centre des matériaux, Evry, France
| | - Lei Wang
- Federal Institute for Materials Research and Testing (BAM), Berlin, Germany
| | - Samuel Forest
- MINES ParisTech, PSL University, MAT - Centre des matériaux, Evry, France
| | - Nikolas Provatas
- Department of Physics and Centre for the Physics of Materials, McGill University, Montreal, Canada
| | - Anssi Laukkanen
- ICME group, VTT Technical Research Centre of Finland Ltd, Espoo, Finland
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15
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Zhu B, Wang Y, Dluhoš J, London AJ, Gorley M, Whiting MJ, Sui T. A novel pathway for multiscale high-resolution time-resolved residual stress evaluation of laser-welded Eurofer97. SCIENCE ADVANCES 2022; 8:eabl4592. [PMID: 35171674 PMCID: PMC8849299 DOI: 10.1126/sciadv.abl4592] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 12/21/2021] [Indexed: 06/14/2023]
Abstract
The plasma-facing components of future fusion reactors, where the Eurofer97 is the primary structural material, will be assembled by laser-welding techniques. The heterogeneous residual stress induced by welding can interact with the microstructure, resulting in a degradation of mechanical properties and a reduction in joint lifetime. Here, a Xe+ plasma focused ion beam with digital image correlation (PFIB-DIC) and nanoindentation is used to reveal the mechanistic connection between residual stress, microstructure, and microhardness. This study is the first to use the PFIB-DIC to evaluate the time-resolved multiscale residual stress at a length scale of tens of micrometers for laser-welded Eurofer97. A nonequilibrium microscale residual stress is observed, which contributes to the macroscale residual stress. The microhardness is similar for the fusion zone and heat-affected zone (HAZ), although the HAZ exhibits around ~30% tensile residual stress softening. The results provide insight into maintaining structural integrity for this critical engineering challenge.
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Affiliation(s)
- Bin Zhu
- Department of Mechanical Engineering Sciences, University of Surrey, Guildford, Surrey GU2 7XH, UK
| | - Yiqiang Wang
- United Kingdom Atomic Energy Authority, Culham Centre for Fusion Energy, Culham Science Centre, Abingdon, Oxon OX14 3DB, UK
| | - Jiří Dluhoš
- TESCAN ORSAY HOLDING, a.s., Libušina třída 21, 623 00 Brno, Czech Republic
| | - Andy J. London
- United Kingdom Atomic Energy Authority, Culham Centre for Fusion Energy, Culham Science Centre, Abingdon, Oxon OX14 3DB, UK
| | - Michael Gorley
- United Kingdom Atomic Energy Authority, Culham Centre for Fusion Energy, Culham Science Centre, Abingdon, Oxon OX14 3DB, UK
| | - Mark J. Whiting
- Department of Mechanical Engineering Sciences, University of Surrey, Guildford, Surrey GU2 7XH, UK
| | - Tan Sui
- Department of Mechanical Engineering Sciences, University of Surrey, Guildford, Surrey GU2 7XH, UK
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16
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Lam TN, Wu YH, Liu CJ, Chae H, Lee SY, Jain J, An K, Huang EW. Transient Phase-Driven Cyclic Deformation in Additively Manufactured 15-5 PH Steel. MATERIALS (BASEL, SWITZERLAND) 2022; 15:777. [PMID: 35160723 PMCID: PMC8836881 DOI: 10.3390/ma15030777] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 01/14/2022] [Accepted: 01/17/2022] [Indexed: 11/19/2022]
Abstract
The present work extends the examination of selective laser melting (SLM)-fabricated 15-5 PH steel with the 8%-transient-austenite-phase towards fully-reversed strain-controlled low-cycle fatigue (LCF) test. The cyclic-deformation response and microstructural evolution were investigated via in-situ neutron-diffraction measurements. The transient-austenite-phase rapidly transformed into the martensite phase in the initial cyclic-hardening stage, followed by an almost complete martensitic transformation in the cyclic-softening and steady stage. The compressive stress was much greater than the tensile stress at the same strain amplitude. The enhanced martensitic transformation associated with lower dislocation densities under compression predominantly governed such a striking tension-compression asymmetry in the SLM-built 15-5 PH.
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Affiliation(s)
- Tu-Ngoc Lam
- Department of Materials Science and Engineering, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan; (T.-N.L.); (Y.-H.W.); (C.-J.L.)
- Department of Physics, College of Education, Can Tho University, Can Tho 900000, Vietnam
| | - Yu-Hao Wu
- Department of Materials Science and Engineering, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan; (T.-N.L.); (Y.-H.W.); (C.-J.L.)
| | - Chia-Jou Liu
- Department of Materials Science and Engineering, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan; (T.-N.L.); (Y.-H.W.); (C.-J.L.)
| | - Hobyung Chae
- Department of Materials Science and Engineering, Chungnam National University, Daejeon 34134, Korea;
| | - Soo-Yeol Lee
- Department of Materials Science and Engineering, Chungnam National University, Daejeon 34134, Korea;
| | - Jayant Jain
- Department of Materials Science and Engineering, Indian Institute of Technology, New Delhi 110016, India
| | - Ke An
- Chemical and Engineering Materials Division, The Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA;
| | - E-Wen Huang
- Department of Materials Science and Engineering, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan; (T.-N.L.); (Y.-H.W.); (C.-J.L.)
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17
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Anisotropy of Mechanical Properties and Residual Stress in Additively Manufactured 316L Specimens. MATERIALS 2021; 14:ma14237176. [PMID: 34885332 PMCID: PMC8658429 DOI: 10.3390/ma14237176] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 11/17/2021] [Accepted: 11/19/2021] [Indexed: 12/02/2022]
Abstract
In the presented study, LPBF 316L stainless steel tensile specimens were manufactured in three different orientations for the analysis of anisotropy. The first set of specimens was built vertically on the build platform, and two other sets were oriented horizontally perpendicular to each other. Tensile test results show that mean Young’s modulus of vertically built specimens is significantly less then horizontal ones (158.7 GPa versus 198 GPa), as well as yield strength and elongation. A role of residual stress in a deviation of tensile loading diagrams is investigated as a possible explanation. Simulation of the build process on the basis of ABAQUS FEA software was used to predict residual stress in 316L cylindrical specimens. Virtual tensile test results show that residual stress affects the initial stage of the loading curve with a tendency to reduce apparent Young’s modulus, measured according to standard mechanical test methods.
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18
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Jreidini P, Pinomaa T, Wiezorek JMK, McKeown JT, Laukkanen A, Provatas N. Orientation Gradients in Rapidly Solidified Pure Aluminum Thin Films: Comparison of Experiments and Phase-Field Crystal Simulations. PHYSICAL REVIEW LETTERS 2021; 127:205701. [PMID: 34860060 DOI: 10.1103/physrevlett.127.205701] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 07/05/2021] [Accepted: 10/19/2021] [Indexed: 06/13/2023]
Abstract
Rapid solidification experiments on thin film aluminum samples reveal the presence of lattice orientation gradients within crystallizing grains. To study this phenomenon, a single-component phase-field crystal (PFC) model that captures the properties of solid, liquid, and vapor phases is proposed to model pure aluminium quantitatively. A coarse-grained amplitude representation of this model is used to simulate solidification in samples approaching micrometer scales. The simulations reproduce the experimentally observed orientation gradients within crystallizing grains when grown at experimentally relevant rapid quenches. We propose a causal connection between defect formation and orientation gradients.
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Affiliation(s)
- Paul Jreidini
- Department of Physics and Centre for the Physics of Materials, McGill University, 3600 University Street, Montreal, QC, H3A 2T8, Canada
| | - Tatu Pinomaa
- Integrated Computational Materials Engineering group, VTT Technical Research Centre of Finland Ltd, Espoo, 02044, Finland
| | - Jörg M K Wiezorek
- Department of Mechanical Engineering and Materials Science, University of Pittsburgh, 636 Benedum Hall, 3700 O'Hara Street, Pittsburgh, Pennsylvania, 15261, USA
| | - Joseph T McKeown
- Materials Sciences Division, Physical and Life Science Directorate, Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California, 94551, USA
| | - Anssi Laukkanen
- Integrated Computational Materials Engineering group, VTT Technical Research Centre of Finland Ltd, Espoo, 02044, Finland
| | - Nikolas Provatas
- Department of Physics and Centre for the Physics of Materials, McGill University, 3600 University Street, Montreal, QC, H3A 2T8, Canada
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19
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Li X, Yi D, Wu X, Zhang J, Yang X, Zhao Z, Wang J, Liu B, Bai P. Study on Mechanism of Structure Angle on Microstructure and Properties of SLM-Fabricated 316L Stainless Steel. Front Bioeng Biotechnol 2021; 9:778332. [PMID: 34805125 PMCID: PMC8595114 DOI: 10.3389/fbioe.2021.778332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 09/23/2021] [Indexed: 11/13/2022] Open
Abstract
In this study, seven 316L stainless steel (316L SS) bulks with different angles (0°, 15°, 30°, 45°, 60°, 75°, and 90°) relative to a build substrate were built via selective laser melting (SLM). The influences of different angles on the metallography, microstructure evolution, tensile properties, and corrosion resistance of 316L SS were studied. The 0° sample showed the morphology of corrugated columnar grains, while the 90° sample exhibited equiaxed grains but with a strong <101> texture. The 60° sample had a good strength and plasticity: the tensile strength with 708 MPa, the yield strength with 588 MPa, and the elongation with 54.51%. The dislocation strengthening and grain refinement play a vital role in the mechanical properties for different anisotropy of the SLM-fabricated 316L SS. The 90° sample had greater toughness and corrosion resistance, owing to the higher volume fraction of low-angle grain boundaries and finer grains.
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Affiliation(s)
- Xiaofeng Li
- School of Materials Science and Engineering, North University of China, Taiyuan, China
- The State Key Laboratory of Powder Metallurgy, Central South University, Changsha, China
| | - Denghao Yi
- School of Materials Science and Engineering, North University of China, Taiyuan, China
- Institute of Laser Engineering, Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing, China
| | - Xiaoyu Wu
- School of Materials Science and Engineering, North University of China, Taiyuan, China
| | - Jinfang Zhang
- School of Materials Science and Engineering, North University of China, Taiyuan, China
- The State Key Laboratory of Powder Metallurgy, Central South University, Changsha, China
| | - Xiaohui Yang
- Instrumental Analysis Center, Taiyuan University of Science and Technology, Taiyuan, China
| | - Zixuan Zhao
- The State Key Laboratory of Powder Metallurgy, Central South University, Changsha, China
| | - Jianhong Wang
- School of Materials Science and Engineering, North University of China, Taiyuan, China
| | - Bin Liu
- The State Key Laboratory of Powder Metallurgy, Central South University, Changsha, China
| | - Peikang Bai
- School of Materials Science and Engineering, North University of China, Taiyuan, China
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20
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The Influence of Metastable Cellular Structure on Deformation Behavior in Laser Additively Manufactured 316L Stainless Steel. NANOMATERIALS 2021; 11:nano11112859. [PMID: 34835624 PMCID: PMC8621913 DOI: 10.3390/nano11112859] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 10/21/2021] [Accepted: 10/22/2021] [Indexed: 11/16/2022]
Abstract
Metastable cellular structures (MCSs) play a crucial role for the mechanical performance in concentrated alloys during non-equilibrium solidification process. In this paper, typifying the heterogeneous 316L stainless steel by laser additive manufacturing (LAM) process, we examine the microstructures in cellular interiors and cellular boundaries in detail, and reveal the interactions of dislocations and twins with cellular boundaries. Highly ordered coherent precipitates present along the cellular boundary, resulting from spinodal decomposition by local chemical fluctuation. The co-existences of precipitates and high density of tangled dislocations at cellular boundaries serve as walls for extra hardening. Furthermore, local chemical fluctuation in MCSs inducing variation in stacking fault energy is another important factor for ductility enhancement. These findings shed light on possible routines to further alter nanostructures, including precipitates and dislocation structures, by tailoring local chemistry in MCSs during LAM.
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21
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Zhang Y, Osetsky YN, Weber WJ. Tunable Chemical Disorder in Concentrated Alloys: Defect Physics and Radiation Performance. Chem Rev 2021; 122:789-829. [PMID: 34694124 DOI: 10.1021/acs.chemrev.1c00387] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The development of advanced structural alloys with performance meeting the requirements of extreme environments in nuclear reactors has been long pursued. In the long history of alloy development, the search for metallic alloys with improved radiation tolerance or increased structural strength has relied on either incorporating alloying elements at low concentrations to synthesize so-called dilute alloys or incorporating nanoscale features to mitigate defects. In contrast to traditional approaches, recent success in synthesizing multicomponent concentrated solid-solution alloys (CSAs), including medium-entropy and high-entropy alloys, has vastly expanded the compositional space for new alloy discovery. Their wide variety of elemental diversity enables tunable chemical disorder and sets CSAs apart from traditional dilute alloys. The tunable electronic structure critically lowers the effectiveness of energy dissipation via the electronic subsystem. The tunable chemical complexity also modifies the scattering mechanisms in the atomic subsystem that control energy transport through phonons. The level of chemical disorder depends substantively on the specific alloying elements, rather than the number of alloying elements, as the disorder does not monotonically increase with a higher number of alloying elements. To go beyond our knowledge based on conventional alloys and take advantage of property enhancement by tuning chemical disorder, this review highlights synergistic effects involving valence electrons and atomic-level and nanoscale inhomogeneity in CSAs composed of multiple transition metals. Understanding of the energy dissipation pathways, deformation tolerance, and structural stability of CSAs can proceed by exploiting the equilibrium and non-equilibrium defect processes at the electronic and atomic levels, with or without microstructural inhomogeneities at multiple length scales. Knowledge of tunable chemical disorder in CSAs may advance the understanding of the substantial modifications in element-specific alloy properties that effectively mitigate radiation damage and control a material's response in extreme environments, as well as overcome strength-ductility trade-offs and provide overarching design strategies for structural alloys.
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Affiliation(s)
- Yanwen Zhang
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States.,Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Yuri N Osetsky
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - William J Weber
- Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States
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22
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Effects of Post Heat Treatments on Microstructures and Mechanical Properties of Selective Laser Melted Ti6Al4V Alloy. METALS 2021. [DOI: 10.3390/met11101593] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The unique thermal history of selective laser melting (SLM) can lead to high residual stress and a non-equilibrium state in as-fabricated titanium alloy components and hinders their extensive use. Post heat treatment, as a classical and effective way, could transform non-equilibrium α’ martensite and achieves desirable mechanical performance in SLMed Ti alloys. In this study, we aimed to establish the correlation between the microstructure and mechanical performances of SLMed Ti6Al4V (Ti-64) by using different heat treatment processes. The columnar prior β grain morphology and grain boundary α phase (GB-α) after different heat treatment processes were characterized, with their influences on the tensile property anisotropy fully investigated. Scanning electron microscope (SEM) observation of the fracture surface and its cross-sectional analysis found that the tensile properties, especially the ductility, were affected by the GB-α along the β grain boundary. Furthermore, the discontinuous ratio of GB-α was firstly proposed to quantitatively predict the anisotropic ductility in SLMed Ti-64. This study provides a step forward for achieving the mechanical property manipulation of SLMed Ti-64 parts.
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23
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An Efficient Methodology towards Mechanical Characterization and Modelling of 18Ni300 AMed Steel in Extreme Loading and Temperature Conditions for Metal Cutting Applications. JOURNAL OF MANUFACTURING AND MATERIALS PROCESSING 2021. [DOI: 10.3390/jmmp5030083] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A thorough control of the machining operations is essential to ensure the successful post-processing of additively manufactured components, which can be assessed through machinability tests endowed with numerical simulation of the metal cutting process. However, to accurately depict the complex metal cutting mechanism, it is not only necessary to develop robust numerical models but also to properly characterize the material behavior, which can be a long-winded process, especially for state-of-stress sensitive materials. In this paper, an efficient mechanical characterization methodology has been developed through the usage of both direct and inverse calibration procedures. Apart from the typical axisymmetric specimens (such as those used in compression and tensile tests), plane strain specimens have been applied in the constitutive law calibration accounting for plastic and damage behaviors. Orthogonal cutting experiments allowed the validation of the implemented numerical model for simulation of the metal cutting processes. Moreover, the numerical simulation of an industrial machining operation (longitudinal cylindrical turning) revealed a very reasonably prediction of cutting forces and chip morphology, which is crucial for the identification of favorable cutting scenarios for difficult-to-cut materials.
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24
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Computational analysis of the effects of geometric irregularities and post-processing steps on the mechanical behavior of additively manufactured 316L stainless steel stents. PLoS One 2020; 15:e0244463. [PMID: 33373392 PMCID: PMC7771678 DOI: 10.1371/journal.pone.0244463] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 12/09/2020] [Indexed: 11/19/2022] Open
Abstract
Advances in additive manufacturing enable the production of tailored lattice structures and thus, in principle, coronary stents. This study investigates the effects of process-related irregularities, heat and surface treatment on the morphology, mechanical response, and expansion behavior of 316L stainless steel stents produced by laser powder bed fusion and provides a methodological approach for their numerical evaluation. A combined experimental and computational framework is used, based on both actual and computationally reconstructed laser powder bed fused stents. Process-related morphological deviations between the as-designed and actual laser powder bed fused stents were observed, resulting in a diameter increase by a factor of 2-2.6 for the stents without surface treatment and 1.3-2 for the electropolished stent compared to the as-designed stent. Thus, due to the increased geometrically induced stiffness, the laser powder bed fused stents in the as-built (7.11 ± 0.63 N) or the heat treated condition (5.87 ± 0.49 N) showed increased radial forces when compressed between two plates. After electropolishing, the heat treated stents exhibited radial forces (2.38 ± 0.23 N) comparable to conventional metallic stents. The laser powder bed fused stents were further affected by the size effect, resulting in a reduced yield strength by 41% in the as-built and by 59% in the heat treated condition compared to the bulk material obtained from tensile tests. The presented numerical approach was successful in predicting the macroscopic mechanical response of the stents under compression. During deformation, increased stiffness and local stress concentration were observed within the laser powder bed fused stents. Subsequent numerical expansion analysis of the derived stent models within a previously verified numerical model of stent expansion showed that electropolished and heat treated laser powder bed fused stents can exhibit comparable expansion behavior to conventional stents. The findings from this work motivate future experimental/numerical studies to quantify threshold values of critical geometric irregularities, which could be used to establish design guidelines for laser powder bed fused stents/lattice structures.
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25
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Abstract
Rapid cooling rates and steep temperature gradients are characteristic of additively manufactured parts and important factors for the residual stress formation. This study examined the influence of heat accumulation on the distribution of residual stress in two prisms produced by Laser Powder Bed Fusion (LPBF) of austenitic stainless steel 316L. The layers of the prisms were exposed using two different border fill scan strategies: one scanned from the centre to the perimeter and the other from the perimeter to the centre. The goal was to reveal the effect of different heat inputs on samples featuring the same solidification shrinkage. Residual stress was characterised in one plane perpendicular to the building direction at the mid height using Neutron and Lab X-ray diffraction. Thermography data obtained during the build process were analysed in order to correlate the cooling rates and apparent surface temperatures with the residual stress results. Optical microscopy and micro computed tomography were used to correlate defect populations with the residual stress distribution. The two scanning strategies led to residual stress distributions that were typical for additively manufactured components: compressive stresses in the bulk and tensile stresses at the surface. However, due to the different heat accumulation, the maximum residual stress levels differed. We concluded that solidification shrinkage plays a major role in determining the shape of the residual stress distribution, while the temperature gradient mechanism appears to determine the magnitude of peak residual stresses.
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26
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Lan L, Xin R, Jin X, Gao S, He B, Rong Y, Min N. Effects of Laser Shock Peening on Microstructure and Properties of Ti-6Al-4V Titanium Alloy Fabricated via Selective Laser Melting. MATERIALS (BASEL, SWITZERLAND) 2020; 13:E3261. [PMID: 32717788 PMCID: PMC7435934 DOI: 10.3390/ma13153261] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 07/17/2020] [Accepted: 07/21/2020] [Indexed: 11/16/2022]
Abstract
Laser shock peening (LSP) is an innovative surface treatment process with the potential to change surface microstructure and improve mechanical properties of additively manufactured (AM) parts. In this paper, the influences of LSP on the microstructure and properties of Ti-6Al-4V (Ti64) titanium alloy fabricated via selective laser melting (SLM), as an attractive AM method, were investigated. The microstructural evolution, residual stress distribution and mechanical properties of SLM-built Ti64 samples were characterized before and after LSP. Results show that the SLM sample was composed of single hcp α' phase, which deviates from equilibrium microstructure at room temperature: α + β phases. The LSP significantly refines the grains of α' phase and produces compressive residual stress (CRS) of maximum magnitude up to -180 MPa with a depth of 250 μm. Grain refinement of α' phase is attributed to the complex interaction of dislocations and the intersection of deformation twinning subjected to LSP treatment. The main mechanism of strength and micro-hardness enhancement via LSP is ascribed to the effects of CRS and α' phase grain refinement.
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Affiliation(s)
- Liang Lan
- School of Material Engineering, Shanghai University of Engineering Science, Shanghai 201620, China; (L.L.); (R.X.); (X.J.); (S.G.)
- Research Center of High-temperature Alloy Precision Forming, Shanghai University of Engineering Science, Shanghai 201620, China
| | - Ruyi Xin
- School of Material Engineering, Shanghai University of Engineering Science, Shanghai 201620, China; (L.L.); (R.X.); (X.J.); (S.G.)
- Research Center of High-temperature Alloy Precision Forming, Shanghai University of Engineering Science, Shanghai 201620, China
| | - Xinyuan Jin
- School of Material Engineering, Shanghai University of Engineering Science, Shanghai 201620, China; (L.L.); (R.X.); (X.J.); (S.G.)
| | - Shuang Gao
- School of Material Engineering, Shanghai University of Engineering Science, Shanghai 201620, China; (L.L.); (R.X.); (X.J.); (S.G.)
- Research Center of High-temperature Alloy Precision Forming, Shanghai University of Engineering Science, Shanghai 201620, China
| | - Bo He
- School of Material Engineering, Shanghai University of Engineering Science, Shanghai 201620, China; (L.L.); (R.X.); (X.J.); (S.G.)
- Research Center of High-temperature Alloy Precision Forming, Shanghai University of Engineering Science, Shanghai 201620, China
| | - Yonghua Rong
- School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China;
| | - Na Min
- Key Laboratory for Microstructures, School of Materials Science and Engineering, Shanghai University, Shanghai 200444, China;
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