A thermomechanical Treatment to Improve superelasticity and Low Modulus of Ti-Nb alloys for Biomedical Applications
Recently, beta Ti alloys consisting of non-cytotoxic elements with low Young modulus have been extensively studied for biomedical applications. In addition to low Young modulus,high strength is also needed to endure stresses. However,it is not easy to achieve low Young modulus and high strength simultaneously. Generally, beta titanium alloys are strengthened by uniform dispersion of very fine omega or alpha precipitates after aging treatment at low temperature followed by quenching. This precipitation is accelerated in heavily deformed beta matrix containing densely distributed dislocations acting as preferential nucleation sites for alpha and omega precipitates. In spite of being effective for strengthening, their presence results in the increase of Youngs modulus. The aim of our study is to find the adequate strategies in order to combine superelasticity and relatively high strength while keeping a low elastic modulus. Many authors have showed that metastable beta Ti alloys can be strengthened with different thermomechanical process. Recently,we have demonstrated that severe cold rolling deformation followed by a flash aging treatment on Ti-(24~26) Nb (at. ％) ,in order to produce ultra fine grains and/or omega phase,is more effective to improve strength and superelasticity. High stress (800MPa),low modulus (30GPa) and recoverable strain (3％) are obtained thanks to this process. These functionalities are due to the stressinduced martensitic transformation and its reverse transformation accompanied with ultra fine beta grain by a flash treatment at 873K or omega precipitation by a flash treatment at 573K. The obtained results on mechanical properties are explained in relation with microstructure evolution during thermomechanical processing in function of annealing time and were investigated using TEM,XRD and EBSD.
Beta titanium low modulus superelasticity martensitic transformation biomaterials
W. Elmay T. Gloriant F. Prima B. Bolle N. Gey E. Patoor P. Laheurte
LEM3 Metz,UMR/CNRS 7239,F-57012 Metz,France INSARennes,UMR CNRS 6226 SCR/Chimie-Métallurgie,F-35708 Rennes,France ENSCP Paris,UMR CNRS 7045 LPCS/Métallurgie Structural,F-75231 Paris,France
国际会议
The 12th World Conference Titanium(第十二届世界钛会 Ti-2011)
北京
英文
2093-2097
2011-06-19（万方平台首次上网日期，不代表论文的发表时间）