The contradiction between the strength and ductility of metallic materials is a major scientific problem that has been researched for a long time.Dual-phase equiatomic and non-equiatomic Ti-Zr-Nb-Ta high-entropy alloys(HEAs)with super-high strength and excellent ductility have been successfully developed via mechanical alloying(MA)combined with spark plasma sintering(SPS)technology.This is adjusted by altering the atomic ratios of the different phases.X-ray diffraction(XRD)and transmission electron microscopy(TEM)were performed to confirm the dual-phase microstructure.After the SPS process,the average grain size of the aforementioned equiatomic Ti25Zr25Nb25Ta25 HEAs(134±50 nm)evaluated by electron back-scattering diffraction(EBSD)is smaller than that of the Ti-Zr-Nb-Ta HEAs(150 μm),which were fabricated using arc melting.According to the Hall-Petch formula,the grain boundary strengthen-ing contribution in the Ti-Zr-Nb-Ta system is 33-fold higher than those fabricated using the arc-melting process.When the alloy phase comprises the equivalent dual-phase,equiatomic Ti25Zr25Nb25Ta25 HEAs have good comprehensive performance compared to non-equiatomic Ti-Zr-Nb-Ta HEAs prepared using the same process.The yield strength of equiatomic Ti25Zr25Nb25Ta25 HEAs(2212±38 MPa)is two-fold higher than that of Ti-Zr-Nb-Ta HEAs(1100±90 MPa)fabricated via arc melting.This can be attributed to the ultra-fine grain size.Notably,the equiatomic Ti25Zr25Nb25Ta25 HEAs possess approximately the same biocompatibility as commercial pure Ti(CP-Ti),indicating that the equiatomic Ti25Zr25Nb25Ta25 HEAs are provided with a possibility as an advanced biomaterial for the applications of the medical field.

Tao Xiang;Peng Du;Zeyun Cai;Kun Li;Weizong Bao;Xinxin Yang;Guoqiang Xie

School of Materials Science and Engineering,Harbin Institute of Technology(Shenzhen),Shenzhen 518055,China;State Key Laboratory of Advanced Welding and Joining,Harbin Institute of Technology,Harbin 150001,China

材料科学技术（英文版）

[1]Tao Xiang;Peng Du;Zeyun Cai;Kun Li;Weizong Bao;Xinxin Yang;Guoqiang Xie-.Phase-tunable equiatomic and non-equiatomic Ti-Zr-Nb-Ta high-entropy alloys with ultrahigh strength for metallic biomaterials)[J].材料科学技术（英文版）,2022(22):196-206

Ti25Zr25Nb25Ta25

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