Ti-Ni-Mo shape memory alloy biomaterial and fixating device for bone fractures using the same alloy

Abstract

The Ti—Ni—Mo shape memory alloy and fixating device for bone fractures using the same are provided, in which a very small amount of Mo of 0.5 at % or 0.7 at % is added Ni for to a Ti—Ni alloy, in order to maintain a transformation temperature whose martensite transformation start temperature (Rs) is 4-35° C. and whose inverse transformation finish temperature (Af) is 6-37° C. to be consistent, so that the transformation temperature can be applied to the human body most ideally, and enhance a corrosion resistivity. The Ti—Ni—Mo shape memory alloy is preferably made of Ti of 48-52 at %, Ni of 48-52 at % and Mo of 0.1-2.0 at %, in a composition ratio. In the case of a B2 (Cubic)⇄R (Rhombohedral)⇄B19′(Monoclinic) transformation, the Ti—Ni—Mo shape memory alloy reduces a variation in a transformation start temperature and an inverse transformation finish temperature according to an annealing temperature change, to thus maintain the transformation temperature constantly. Also, the Ti—Ni—Mo shape memory alloy possesses the most appropriate transformation temperature to be applied to the human body and an enhanced corrosion resistivity when an amount of Mo added is increased, and reduces Ni dissolution quantity as can be seen from Ni dissolution test to thereby enhance biocompatibility in the human body.

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