Physical and Biochemical Principles of the Application of TiNi-Based Alloys as Shape-Memory Implants

Abstract

For medical treatment of various diseases and traumas, there is a wide distribution of the metallic, ceramic and polymer applications for the realization of different functions in living organisms. Such constructions are being called implants. Materials for medical implants (biomaterials) need to satisfy three important demands, i.e. (1) - the reliability of the mechanical functions, (2) chemical reliabilities - the resistance to deterioration of their properties in a biological medium, the resistance to expansion, dissolution, corrosion, and (3) biological reliabilities - biological compatibility, lack of toxicity and carcinogenicity, resistance to the formation of thrombus and antigens [1]. Biomaterials should be non-toxic during the implanted period in the body and, simultaneously, have rather high physical-mechanical characteristics. Because of these rigorous demands, only the following three metallic materials have been qualified to be available as implant materials, i.e. Fe-Cr-Ni, Co-Cr and Ti-Al-V [2]. However, shape memory alloys have been recently introduced to medicine, since they have unique functions such as shape memory effect, superelasticity and damping capacity.