Elastic modulus and structure of pure titanium and titanium alloy

摘要

It is desirable that metallic implant materials consist of non-cytotoxic elements and have similar mechanical properties, especially young's modulus, with human bone. Titanium, niobium and chromium are recognized as non-or minimal-cytotoxic elements. However, young's modulus of titanium (106GPa), niobium (103GPa) and chromium (245GPa) is much highe than taht of human bone (10GPa～30GPa). Young's modulus of pure titamium, Ti-Nb and Ti-Cr alloys is investigated in relation to their microstructure. Young's modulus of pure titanium produced by powder metallurgy, changing parameters of mechanical grinding and sintering condition, decreases linearly from 110GPa to 27GPa with increasing amounts of pore. It is known that young's modulus of meta-stable beta titanium alloy containing beta-isomorphous alloy elements of niobium or tantalum is low, though it depends on amounts of alloy elements. Ti-Nb alloy and also Ti-Cr alloy produced by powder metallurgy in this experiment showed lower young's modulus than oure titanium. Thus, beta-eutectoid stabilized element of chromium was found to have the similar effect on the decrease of young's modulus of titanium alloy with beta-isomorphous element of niobium.