Relationship between various deformation-induced products and mechanical properties in metastable Ti-30Zr-Mo alloys for biomedical applications

Nowadays, there is a significant research focus on the development of bio-implant materials that have not only a low Young's modulus but also other unique characteristics such as a changeable Young's modulus and the ability to prevent calcium phosphate formation. Taking advantage of deformation-induced phases is an effective way to obtain the changeable Young's modulus. This study investigated the relationship between the various deformation-induced products and the mechanical properties - including Young's modulus, microstructure, and tensile properties - of Ti-30Zr-(5,6,7)mass%Mo alloys subjected to solution treatment (ST) and cold-rolling (CR). After ST, each alloy is composed of a beta phase and a small amount of athermally formed omega phase, and exhibits a low Young's modulus. During CR, deformation-induced phase transformation occurs in all the alloys. The change in Young's modulus due to CR is highly dependent on the types of deformation-induced products. The decrease in Young's modulus due to CR is related to the deformation-induced alpha' phase transformation accompanying with the disappearance of athermal omega phase, and the increase in Young's modulus is attributed to the deformation-induced omega phase, which mainly exists in {332}(beta) mechanical twins. (C) 2011 Elsevier Ltd. All rights reserved.