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Cojocaru VD, Șerban N, Cojocaru EM, Zărnescu-Ivan N, Gălbinașu BM. The Effect of Solution Treatment Duration on the Microstructural and Mechanical Properties of a Cold-Deformed-by-Rolling Ti-Nb-Zr-Ta-Sn-Fe Alloy. MATERIALS (BASEL, SWITZERLAND) 2024; 17:864. [PMID: 38399115 PMCID: PMC10890699 DOI: 10.3390/ma17040864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2023] [Revised: 01/21/2024] [Accepted: 01/24/2024] [Indexed: 02/25/2024]
Abstract
The study presented in this paper is focused on the effect of varying the solution treatment duration on both the microstructural and mechanical properties of a cold-deformed by rolling Ti-30Nb-12Zr-5Ta-2Sn-1.25Fe (wt.%) alloy, referred to as TNZTSF. Cold-crucible induction using the levitation synthesis technique, conducted under an argon-controlled atmosphere, was employed to fabricate the TNZTSF alloy. After synthesis, the alloy underwent cold deformation by rolling, reaching a total deformation degree (total applied thickness reduction) of 60%. Subsequently, a solution treatment was conducted at 850 °C, with varying treatment durations ranging from 2 to 30 min in 2 min increments. X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques were utilized for the structural analysis, while the mechanical properties were assessed using both tensile and hardness testing. The findings indicate that (i) in both the cold-deformed-by-rolling and solution-treated states, the TNZTSF alloy exhibits a microstructure consisting of a single β-Ti phase; (ii) in the solution-treated state, the microstructure reveals a rise in the average grain size and a decline in the internal average microstrain as the duration of the solution treatment increases; and (iii) owing to the β-phase stability, a favorable mix of elevated strength and considerable ductility properties can be achieved.
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Affiliation(s)
- Vasile Dănuț Cojocaru
- Faculty of Materials Science and Engineering, National University of Science and Technology Politehnica of Bucharest, 060042 Bucharest, Romania; (V.D.C.); (N.Ș.); (E.M.C.)
| | - Nicolae Șerban
- Faculty of Materials Science and Engineering, National University of Science and Technology Politehnica of Bucharest, 060042 Bucharest, Romania; (V.D.C.); (N.Ș.); (E.M.C.)
| | - Elisabeta Mirela Cojocaru
- Faculty of Materials Science and Engineering, National University of Science and Technology Politehnica of Bucharest, 060042 Bucharest, Romania; (V.D.C.); (N.Ș.); (E.M.C.)
| | - Nicoleta Zărnescu-Ivan
- Faculty of Materials Science and Engineering, National University of Science and Technology Politehnica of Bucharest, 060042 Bucharest, Romania; (V.D.C.); (N.Ș.); (E.M.C.)
| | - Bogdan Mihai Gălbinașu
- Dental Medicine Faculty, University of Medicine and Pharmacy “Carol Davila” Bucharest, 020021 Bucharest, Romania;
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Răducanu D, Nocivin A, Cojocaru VD, Șerban N, Zărnescu-Ivan N, Irimescu RE, Gălbinașu BM. Microstructural Considerations of a Multi-Pass Rolled Ti-Nb-Ta-Zr Alloy. MATERIALS (BASEL, SWITZERLAND) 2023; 16:3208. [PMID: 37110044 PMCID: PMC10144209 DOI: 10.3390/ma16083208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 04/05/2023] [Accepted: 04/12/2023] [Indexed: 06/19/2023]
Abstract
The microstructural characteristic evolution was investigated during thermomechanical processing of Ti-29Nb-9Ta-10Zr (wt %) alloy, which consisted of, in a first stage, in a Multi-Pass Rolling with increasing thickness reduction of 20%, 40%, 60%, 80%, and 90%; in step two, the multi-pass rolled sample with the highest thickness reduction (90%) was subjected to a series of three variants of static short recrystallization and then to a final similar aging. The objective was to evaluate the microstructural features evolution during thermomechanical processing (phase's nature, morphology, dimensions, and crystallographic characteristics) and to find the optimal heat treatment variant for refinement of the alloy granulation until ultrafine/nanometric level for a promising combination of mechanical properties. The microstructural features were investigated by X-ray diffraction and SEM techniques through which the presence of two phases was recorded: the β-Ti phase and the α″-Ti martensitic phase. The corresponding cell parameters, dimensions of the coherent crystallite and the micro-deformations at the crystalline network level for both recorded phases were determined. The majority β-Ti phase underwent a strong refinement during the Multi-Pass Rolling process until ultrafine/nano grain dimension (about 9.8 nm), with subsequent slow growing during recrystallization and aging treatments, hindered by the presence of sub-micron α″-Ti phase dispersed inside β-Ti grains. An analysis concerning the possible deformation mechanisms was performed.
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Affiliation(s)
- Doina Răducanu
- Department of Metallic Materials Processing and Environmental Engineering, University Politehnica of Bucharest, 060042 Bucharest, Romania; (D.R.); (V.D.C.); (N.Ș.); (N.Z.-I.)
| | - Anna Nocivin
- Faculty of Mechanical, Industrial and Maritime Engineering, Ovidius University of Constanta, 900527 Constanța, Romania;
| | - Vasile Dănuț Cojocaru
- Department of Metallic Materials Processing and Environmental Engineering, University Politehnica of Bucharest, 060042 Bucharest, Romania; (D.R.); (V.D.C.); (N.Ș.); (N.Z.-I.)
| | - Nicolae Șerban
- Department of Metallic Materials Processing and Environmental Engineering, University Politehnica of Bucharest, 060042 Bucharest, Romania; (D.R.); (V.D.C.); (N.Ș.); (N.Z.-I.)
| | - Nicoleta Zărnescu-Ivan
- Department of Metallic Materials Processing and Environmental Engineering, University Politehnica of Bucharest, 060042 Bucharest, Romania; (D.R.); (V.D.C.); (N.Ș.); (N.Z.-I.)
| | - Raluca Elena Irimescu
- Department of Metallic Materials Processing and Environmental Engineering, University Politehnica of Bucharest, 060042 Bucharest, Romania; (D.R.); (V.D.C.); (N.Ș.); (N.Z.-I.)
| | - Bogdan Mihai Gălbinașu
- Dental Medicine Faculty, University of Medicine and Pharmacy “Carol Davila” Bucharest, 020021 Bucharest, Romania;
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Dan A, Cojocaru EM, Raducanu D, Nocivin A, Cinca I, Cojocaru VD. {332}<113> and {112}<111> Twin Variant Activation during Cold-Rolling of a Ti-Nb-Zr-Ta-Sn-Fe Alloy. MATERIALS (BASEL, SWITZERLAND) 2022; 15:6932. [PMID: 36234273 PMCID: PMC9573394 DOI: 10.3390/ma15196932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 09/25/2022] [Accepted: 10/03/2022] [Indexed: 06/16/2023]
Abstract
Deformation twinning is a phenomenon that causes local shear strain concentrations, with the material either experiencing elongation (and thus a tensile stress) or contraction (compressive stress) along the stress directions. Thus, in order to gauge the performance of the alloy better, it is imperative to predict the activation of twinning systems successfully. The present study investigates the effects of deformation by cold-rolling on the {332}<113> and {112}<111> twin variant activation in a Ti-30Nb-12Zr-5Ta-2Sn-1.25Fe (wt.%) (TNZTSF) alloy. The Ti-30Nb-12Zr-5Ta-2Sn-1.25Fe (wt.%) alloy was synthesized in a cold crucible induction levitation furnace, under an argon-controlled atmosphere, using high-purity elemental components. The TNZTSF alloy was cold-deformed by rolling, in one single step, with a total deformation degree (thickness reduction) of ε ≈ 1% (CR 1), ε ≈ 3% (CR 3), and ε ≈ 15% (CR 15). The microstructural investigations were carried out with the SEM-EBSD technique in order to determine the grain morphology, grain-size distribution, crystallographic orientation, accumulated strain-stress fields and Schmid Factor (SF) analysis, all necessary to identify the active twin variants. The EBSD data were processed using an MTEX Toolbox ver. 5.7.0 software package. The results indicated that the TNZTSF alloy’s initial microstructure consists of a homogeneous β-Ti single phase that exhibits equiaxed polyhedral grains and an average grain-size close to 71 μm. It was shown that even starting with a 1% total deformation degree, the microstructure shows the presence of the {332}<113> twinning ((233)[3¯11] active twin variant; Schmit factor SF = −0.487); at a 3% total deformation degree, one can notice the presence of primary and secondary twin variants within the same grain belonging to the same {332}<113> twinning system ((323¯)[13¯1¯] primary twin variant—SF = −0.460; (233¯)[3¯11¯] secondary twin variant—SF = −0.451), while, at a 15% total deformation degree, besides the {332}<113> twinning system, one can notice the activation of the {112}<111> twinning system ((11¯2)[1¯11] active twin variant—SF = −0.440). This study shows the {332}<113> and {112}<111> twinning variant activation during cold-deformation by rolling in the case of a Ti-30Nb-12Zr-5Ta-2Sn-1.25Fe (wt.%) (TNZTSF) alloy.
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Affiliation(s)
- Alexandru Dan
- Department of Metallic Materials Processing, University Politehnica of Bucharest, 060042 Bucharest, Romania
| | - Elisabeta Mirela Cojocaru
- Department of Metallic Materials Processing, University Politehnica of Bucharest, 060042 Bucharest, Romania
| | - Doina Raducanu
- Department of Metallic Materials Processing, University Politehnica of Bucharest, 060042 Bucharest, Romania
| | - Anna Nocivin
- Department of Industrial Management, Ovidius University of Constanța, 900527 Constanța, Romania
| | - Ion Cinca
- Department of Metallic Materials Processing, University Politehnica of Bucharest, 060042 Bucharest, Romania
| | - Vasile Danut Cojocaru
- Department of Metallic Materials Processing, University Politehnica of Bucharest, 060042 Bucharest, Romania
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Dan A, Angelescu ML, Serban N, Cojocaru EM, Zarnescu-Ivan N, Cojocaru VD, Galbinasu BM. Evolution of Microstructural and Mechanical Properties during Cold-Rolling Deformation of a Biocompatible Ti-Nb-Zr-Ta Alloy. MATERIALS 2022; 15:ma15103580. [PMID: 35629608 PMCID: PMC9143921 DOI: 10.3390/ma15103580] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 05/14/2022] [Accepted: 05/16/2022] [Indexed: 11/26/2022]
Abstract
In this study, a Ti-32.9Nb-4.2Zr-7.5Ta (wt%) titanium alloy was produced by melting in a cold crucible induction in a levitation furnace, and then deforming by cold rolling, with progressive deformation degrees (thickness reduction), from 15% to 60%, in 15% increments. The microstructural characteristics of the specimens in as-received and cold-rolled conditions were determined by XRD and SEM microscopy, while the mechanical characteristics were obtained by tensile and microhardness testing. It was concluded that, in all cases, the Ti-32.9Nb-4.2Zr-7.5Ta (wt%) showed a bimodal microstructure consisting of Ti-β and Ti-α″ phases. Cold deformation induced significant changes in the microstructural and the mechanical properties, leading to grain-refinement, crystalline cell distortions and variations in the weight-fraction ratio of both Ti-β and Ti-α″ phases, as the applied degree of deformation increased from 15% to 60%. Changes in the mechanical properties were also observed: the strength properties (ultimate tensile strength, yield strength and microhardness) increased, while the ductility properties (fracture strain and elastic modulus) decreased, as a result of variations in the weight-fraction ratio, the crystallite size and the strain hardening induced by the progressive cold deformation in the Ti-β and Ti-α″ phases.
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Affiliation(s)
- Alexandru Dan
- Faculty of Materials Science and Engineering, University Politehnica of Bucharest, 060042 Bucharest, Romania; (A.D.); (M.L.A.); (N.S.); (E.M.C.); (N.Z.-I.)
| | - Mariana Lucia Angelescu
- Faculty of Materials Science and Engineering, University Politehnica of Bucharest, 060042 Bucharest, Romania; (A.D.); (M.L.A.); (N.S.); (E.M.C.); (N.Z.-I.)
| | - Nicolae Serban
- Faculty of Materials Science and Engineering, University Politehnica of Bucharest, 060042 Bucharest, Romania; (A.D.); (M.L.A.); (N.S.); (E.M.C.); (N.Z.-I.)
| | - Elisabeta Mirela Cojocaru
- Faculty of Materials Science and Engineering, University Politehnica of Bucharest, 060042 Bucharest, Romania; (A.D.); (M.L.A.); (N.S.); (E.M.C.); (N.Z.-I.)
| | - Nicoleta Zarnescu-Ivan
- Faculty of Materials Science and Engineering, University Politehnica of Bucharest, 060042 Bucharest, Romania; (A.D.); (M.L.A.); (N.S.); (E.M.C.); (N.Z.-I.)
| | - Vasile Danut Cojocaru
- Faculty of Materials Science and Engineering, University Politehnica of Bucharest, 060042 Bucharest, Romania; (A.D.); (M.L.A.); (N.S.); (E.M.C.); (N.Z.-I.)
- Correspondence: ; Tel.: +40-21-402-95-31
| | - Bogdan Mihai Galbinasu
- Dental Medicine Faculty, University of Medicine and Pharmacy “Carol Davila” Bucharest, 020021 Bucharest, Romania;
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Effects of Cold Rolling Deformation and Solution Treatment on Microstructural, Mechanical, and Corrosion Properties of a Biocompatible Ti-Nb-Ta-Zr Alloy. METALS 2022. [DOI: 10.3390/met12020248] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
One of the most important requirements for a metallic biomaterial is the mechanical biocompatibility, which means excellent mechanical properties—high strength and fatigue strength, but low elastic modulus, to be mechanically harmonized with hard tissues. In order to improve the mechanical and biocompatible performance of the Ti-25.5Nb-4.5Ta-8.0Zr wt% alloy, the influence of cold plastic deformation and solution treatment on its properties were investigated. The Ti-25.5Nb-4.5Ta-8.0Zr wt% alloy was fabricated by melting in a cold crucible furnace (in levitation) and then subjected to several treatment schemes, which include cold rolling and different solution treatments. Microstructural and mechanical characteristics of specimens in as-cast and thermo-mechanically processed condition were determined by SEM microscopy and tensile testing, for different structural states: initial as-cast/as-received, cold rolled and solution treated at different temperatures (800, 900, and 1000 °C) and durations (5, 10, 15, and 20 min), with water quenching. It was concluded that both cold rolling and solution treatment have important positive effects on structural and mechanical properties of the biomaterial, increasing mechanical strength and decreasing the elastic modulus. Samples in different structural states were also corrosion tested and the results provided important information on determining the optimal processing scheme to obtain a high-performance biomaterial. The final processing route chosen consists of a cold rolling deformation with a total deformation degree of 60%, followed by a solution heat treatment at 900 °C with maintenance duration of 5 min and water quenching. By applying this thermo-mechanical processing scheme, the Ti-25.5Nb-4.5Ta-8.0Zr wt% alloy showed an elastic modulus of 56 GPa (5% higher than in the as-cast state), an ultimate tensile strength of 1004 MPa (41.8% higher than in the as-cast state), a yield strength of 718 MPa (40.6% higher than in the as-cast state), and increased corrosion resistance (the corrosion rate decreased by 50% compared to the as-cast state).
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Impact of Preparation of Titanium Alloys on Their Abrasive Water Jet Machining. MATERIALS 2021; 14:ma14247768. [PMID: 34947362 PMCID: PMC8703524 DOI: 10.3390/ma14247768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 12/07/2021] [Accepted: 12/13/2021] [Indexed: 11/17/2022]
Abstract
Several titanium alloys, i.e., grade 2 Ti, Ti6Al4V and NiTi alloy, prepared by selected deformation procedures were subjected to abrasive water jet (AWJ) cutting and subsequently analysed. The study describes samples’ preparations and respective material structures. The impact of deformation processing of the selected alloys on the declination angle during cutting, and the results of measurements of surface wall quality performed for the selected samples at the Department of Physics of Faculty of Electrical Engineering and Computer Science at VŠB–Technical University of Ostrava, are presented and discussed, as are also the influences of structural features of the processed titanium alloys on surface qualities of the investigated samples. The results showed that the highest resistance to AWJ machining exhibited the Ti6Al4V alloy prepared by forward extrusion. Its declination angle (recalculated to the thickness 10 mm to compare all the studied samples) was 12.33° at the traverse speed of 100 mm/min, pumping pressure of 380 MPa, and abrasive mass flow rate of 250 g/min.
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Microstructural Evolution and Tensile Testing of a Bi–Sn (57/43) Alloy Processed by Tube High-Pressure Shearing. CRYSTALS 2021. [DOI: 10.3390/cryst11101229] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Tube high-pressure shearing (t-HPS) processing was performed on a eutectic Bi–Sn (57/43) alloy for 0.25, 1, 5 and 20 turns. The selected samples were stored at room temperature for up to 56 days to examine the strain weakening and self-annealing behavior of the alloy. The results showed that t-HPS processing gradually refined the microstructure and led to decreasing of microhardness, but microhardness increased slowly during the subsequent storage at room temperature. Shear localization of the eutectic structure during t-HPS processing was observed as large amounts of narrow dense lamellar zones were visible in the deformed microstructures. The Bi–Sn (57/43) alloy processed by t-HPS exhibited significantly enhanced superplastic properties with elongations up to >1800% in a sample after t-HPS processing for 20 turns. This high elongation is attributed to the breaking of the lamellar structure and the very small grain size.
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