Design and development of Ti–Zr–Hf–Nb–Ta–Mo high-entropy alloys for metallic biomaterials
Yuuka Iijima, Takeshi Nagase, Aira Matsugaki, Pan Wang, Kei Ameyama, Takayoshi Nakano
Abstract
Applying empirical alloy parameters (including Mo equivalent), the predicted ground state diagram, and thermodynamic calculations, noble nonequiatomic Ti–Zr–Hf–Nb–Ta–Mo high-entropy alloys for metallic biomaterials (BioHEAs) were designed and newly developed. It is found that the Moeq and valence electron concentration (VEC) parameters are useful for alloy design involving BCC structure formation in bio medium-entropy alloys and BioHEAs. Finally, we find a Ti28.33Zr28.33Hf28.33Nb6.74Ta6.74Mo1.55 (at.%) BioHEA that exhibits biocompatibility comparable to that of CP–Ti, higher mechanical strength than CP–Ti, and an appreciable room-temperature tensile ductility. The current findings pave the way for new Ti–Zr–Hf–Nb–Ta–Mo BioHEAs development and are applicable for another BioHEA alloys system.