Martensitic transformation and mechanical properties of AuCuAl-based biomedical shape memory alloys containing various quaternary elements

Abstract

Although AuCuAl shape memory alloys are hopeful as advanced functional biomaterials exhibiting shape memory effect and good X-ray radiography, the limited ductility in polycrystalline materials is a drawback for practical applications. In this study, effects of quaternary elements (B, Ti, Zr, Cr, Mn, Fe, Zn, In and Sn) on martensitic transformation start temperature (Ms) and mechanical properties are investigated. It was found that (1) Mn, Fe, In and Sn additions decrease Ms and that (2) B, Ti, Zr, Cr and Zr additions do not affect or slightly increase Ms. Among the quaternary additions investigated, only Fe addition drastically improves ductility. Therefore, Fe is concluded to be the effective additional element to bring both sufficiently low Ms and ductility to AuCuAl alloys.