Mechanical, Corrosion, and Wear Properties of TiZrTaNbSn Biomedical High-Entropy Alloys

The phase composition, microstructure, mechanical, corrosion, and wear behaviors of the Ti15Zr35Ta10Nb10Sn30 (Sn30) and Ti15Zr30Ta10Nb10Sn35 (Sn35) biomedical high-entropy alloys (BHEAs) were studied. We found that the Ti–Zr–Ta–Nb–Sn BHEAs showed hyper-eutectic and eutectic structures with body-centered cubic (BCC) and face-centered cubic (FCC) solid-solution phases. The Sn30 BHEA exhibited a high Vickers hardness of approximately 501.2 HV, a compressive strength approaching 684.5 MPa, and plastic strain of over 46.6%. Furthermore, the Vickers hardness and compressive strength of Sn35 BHEA are 488.7 HV and 999.2 MPa, respectively, with a large plastic strain of over 49.9%. Moreover, the Sn30 and Sn 35 BHEA friction coefficients are 0.152 and 0.264, respectively. Sn30 BHEA has the smallest and shallowest furrow-groove width, and its wear rate is 0.86 (km/mm3); at the same time, we observed the delamination phenomenon. Sn35 BHEA has a wear rate value of 0.78 (km/mm3), and it displays wear debris and the largest–deepest furrow groove. Sn30 BHEA has the highest impedance value, and its corrosion current density Icorr is 1.261 × 10−7 (A/cm2), which is lower than that of Sn35 BHEA (1.265 × 10−6 (A/cm2)) by 88%, and the passivation current density Ipass of Sn30 BHEA and Sn35 BHEA is 4.44 × 10−4 (A/cm2) and 3.71 × 10−3 (A/cm2), respectively. Therefore, Sn30 BHEA preferentially produces passive film and has a small corrosion tendency, and its corrosion resistance is considerably better than that of the Sn35 BHEA alloy.