Microstructure evolution and deformation mechanism of alpha plus beta dual-phase Ti-xNb-yTa-2Zr alloys with high performance
Biomedical beta-phase Ti-Nb-Ta-Zr alloys usually exhibit low elastic modulus with inadequate strength. In the present work, a series of newly developed dual-phase Ti-xNb-yTa-2Zr (wt.%) alloys with high performance were investigated in which the stability of beta-phase was reduced under the guideline...
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| Published in: | Journal of materials science & technology 2022-12, Vol.131, p.68 |
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| Main Authors: | , , , , , , , , , |
| Format: | Article |
| Language: | eng |
| Subjects: | |
| Online Access: | Get full text |
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| Summary: | Biomedical beta-phase Ti-Nb-Ta-Zr alloys usually exhibit low elastic modulus with inadequate strength. In the present work, a series of newly developed dual-phase Ti-xNb-yTa-2Zr (wt.%) alloys with high performance were investigated in which the stability of beta-phase was reduced under the guidelines of ab initio calculations and d-electronic theory. The effects of Nb and Ta contents on the microstructure, compressive and tensile properties were investigated. Results demonstrate that the designed Ti-xNb-yTa-2Zr alloys exhibit typical characteristics of alpha+beta dual-phase microstructure. The microstructure of the alloys is more sensitive to Nb rather than Ta. The as-cast alloys exhibit needle-like alpha' martensite at a lower Nb content of 3 wt.% and lamellar alpha' martensite at an Nb content of 5 wt.%. Among the alloys, the Ti-3Nb-13Ta-2Zr alloy shows the highest compressive strength (2270 +/- 10 MPa) and compressive strain (74.3% +/- 0.4%). This superior performance is due to the combination of alpha+beta dual-phase microstructure and stress-induced alpha '' martensite. Besides, lattice distortion caused by Ta element also contributes to the compressive properties. Nb and Ta contents of the alloys strongly affect Young's modulus and tensile properties after rolling. The as-rolled Ti-3Nb-13Ta-2Zr alloy exhibits much lower modulus due to lower Nb content as well as more alpha '' martensite and beta phase with a good combination of low modulus and high strength among all the designed alloys. Atom probe tomography analysis reveals the element partitioning between the a and beta phases in which Ta concentration is higher than Nb in the alpha phase. Also, the concentration of Ta is lower than that of Nb in the beta phase, indicating that the beta-stability of Nb is higher than that of Ta. This work proposes modern alpha+beta dual-phase Ti-xNb-yTa-2Zr alloys as a new concept to design novel biomedical Ti alloys with high performance. |
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| ISSN: | 1005-0302 1941-1162 |