Texture Development And Its Effect On Anisotropy Of Young’s Modulus Of Metastableβ Type Titanium Alloy For Biomedical Applications

Research and development on the titanium alloys for biomedical applications are of great economic and social benefits. Recently, β type titanium alloys have become a new generation of biomedical materials for their excellent comprehensive performance. According to the application requirements of biomedical materials, a new kind of TiNbZrFe metastable β type titanium alloy was designed in present thesis. The deformation texture and recrystallization texture evolution in cold rolling process and annealing process were investigated by Electron Backscattering Diffraction (EBSD) and X-Ray diffraction (XRD) methods respectively, and the effects of texture and microstructure on tensile properties especially on Young’s modulus were examined. The research results supplied a theoretical basis for the development and research on biomedical titanium alloy.Deformation textures in TNZF alloy produced by different cold rolling reduction were composed of a and y fibers accompany with little Cube and Goss, including {112}<110>,{113}<110>and{111}<110>,{111}<112> respectively. The orientation densities of a and y fibers gradually increased when rolling reduction changed from20%to60%, while decreased under90%reduction. The experimental results showed that the sequence of Young’s modulus along the tensile testing angle of RD and TD was ERD<ETD all the time simultaneously, because the<110> texture played a leading role all the time and<112> texture was relatively weak. Increasing rolling reduction to40%,<110> texture strengthened, together with the formation of<112> texture, which reduced ERD and ETD significantly. With increasing the rolling reduction,<110> texture strengthened continuously, while<112> texture weakened, which decreased ERD clearly and increased ETD slightly. But when rolling reduction increased to90%,<110> texture strengthened continuously,<112> texture weakened a little, while<100> texture produced, which increased ETD slightly and decreased ERD effectively to63.4GPa. Orientation of the TNZF alloy changed with recrystallization annealing temperature clearly. Nucleation occurred when annealing at550～700℃after90%cold rolling reduction.<110> fiber texture was weakened continuously, while{111}<112> texture formed gradually, and Young’s modulus had no significant change as a result of the weakening of the total texture andthe increasing of random orientation. Recrystallized grains grew along preferred orientation when the annealing temperature increased from700℃to900℃and that made{111}<112> texture strengthen significantly. Young’s modulus of the alloy decreased obviously with increasing temperature. When annealing at900℃, the alloy had the lowest Young’s modulus of41GPa.