Laser-assisted synthesis of Ti–Mo alloys for biomedical applications

Abstract

This paper presents the results of a laser-based combinatorial investigation of the Ti–Mo system, aiming at finding alloys with promising properties for orthopedic applications. Variable powder feed rate laser cladding was applied to synthesize Ti–xMo alloys with composition continuously varying in the range of 4–19wt.% Mo. Screening was performed on the basis of the alloys' mechanical properties, in particular hardness and Young's modulus, measured by microindentation tests. Microstructural analysis showed that alloys with Mo content between 4 and 8wt.% are composed of acicular martensite and retained β-phase, the proportion of the later phase increasing with increasing Mo content. Alloys with Mo content of 10wt.% and higher consist entirely of β phase. All the alloys present a Mo segregation pattern indicating that solidification occurred with a cellular solid–liquid interface. Though β-phase alloys present lower values of Young's modulus and hardness than α′- or α″- containing alloys, minimum values of Young's modulus (75GPa) and hardness (240VHN) were achieved for the Ti–13wt.% Mo alloy.