| Summary: | Biocompatible β-type Ti-45Nb alloy with a low elastic modulus is promising in alleviating the stress shielding effect of Ti-based hard-tissue replacement implants. In this work, the ultra-fine-grained (UFG) microstructures with different grain sizes were prepared by multi-axial compression (MAC) processing of Ti-45Nb alloys, and the mechanical properties and the fretting wear properties of Ti-45Nb alloys in different grain sizes were investigated. The results show that the yield strength and ultimate tensile strength of the sample processed by 27 passes MAC increase by 76% and 91%, respectively, with an elongation of more than 9%. After MAC processing, the friction coefficient and volume wear rate gradually decrease. In addition, before MAC processing, the Ti-45Nb sample shows a wear mechanism of severe adhesive wear, oxidative wear and fatigue delamination; while after MAC processing, the wear mechanism switches to abrasive wear and slight adhesive wear with slight oxidative wear, indicating that grain refinement helps to improve the anti-fretting properties of Ti-45Nb alloys.
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