Revealing the fundamental relationship between the properties and microstructures of biomedical TiZrTaNbMo high entropy alloy

The body-centered cubic high-entropy alloys are a promising candidate as implanting materials for biomedical areas, but their severe strength-ductility trade-off limits their application. Herein, we designed and prepared the biomedical TiZrTaNbMo HEAs with different atomic ratios by adjusting their elemental composition based on the theoretical calculation of negative mixing enthalpy and valence electron concentration. It was found that the (TiZr)₄₇(TaNbMo)₂ alloy has BCC and HCP mixing structure, and the (TiZr)_42.5(TaNbMo)₅ and the (TiZr)₄₅(TaNbMo)_3.33 have simple BCC structure. the yield strength (YS) and total tensile elongation of the (TiZr)_42.5(TaNbMo)₅, (TiZr)₄₅(TaNbMo)_3.33, (TiZr)₄₇(TaNbMo)₂ are 866 ± 28 MPa and 16.5 ± 1.1 %, 929 ± 13 MPa and 17.8 ± 1.2 %, 899 ± 6 MPa and 5.5 ± 0.1 %, respectively. The theoretical calculation shows that the high YS strength mainly comes from the solid solution strengthening effect, the high ductility can be explained by the negative mixing enthalpy induced by Mo element. In addition, the (TiZr)₄₅(TaNbMo)_3.33 alloy has better wear resistance and corrosion resistance than the commercially available Ti6Al4V. This study shed light on synthesizing the high entropy alloy with the desired comprehensive properties as biomedical implant materials. © 2024  Elsevier B.V.