Improvement of microstructure, mechanical and corrosion properties of biomedical Ti-Mn alloys by Mo addition

摘要

In previous studies, Ti-Mn alloys showed promising performance for biomedical applications, but their elongation required improvement. In this study, Mo was added to Ti-Mn alloys to promote mechanical twinning and improve their ductility. Four alloys for biomedical applications were designed and fabricated by cold crucible levitation melting: Ti-5Mn-3Mo (TMM-53), Ti-5Mn-4Mo (TMM-54), Ti-6Mn-3Mo (TMM-63), and Ti-6Mn-4Mo (TMM-64). The microstructure, mechanical properties, tensile deformation mechanisms, and electrochemical corrosion properties of the alloys were evaluated. Their hardness ranges from 336 to 373 HV. Their Young's modulus ranges from 89 to 100 GPa. Both hardness and Young's modulus tend to decrease with decreasing amount of athermal omega phase, which is caused by increasing alloying elements contents. Mo addition improves the elongation of TMM-53 and TMM-54 by promoting twinning. Conversely, it increases the tensile strength of TMM-63 and TMM-64. Particularly, TMM-54 shows an elongation of 34% with an ultimate tensile strength (UTS) of 935 MPa. TMM-63 shows an elongation of 14% and a UTS of 1220 MPa, associated to the formation of deformation-induced to phase. Moreover, Mo addition decreases the corrosion rate of the Ti-Mn alloys to a level comparable to that of commercially-pure Ti. (C) 2016 Elsevier Ltd. All rights reserved.