Effect of Pre-Rolling Strategy and Aging Precipitation Behaviors on Mechanical Properties and Wear Resistance of Biomedical Ti-15Mo Alloy

The precipitation behaviors of aging (A) were investigated in Ti-15Mo alloy after solution treatment (ST), unidirectional rolling (Uni-R) and bidirectional rolling (Bi-R). The results indicate that pre-rolling followed aging treatment could obtain fine alpha precipitates and improve the performance of the alloy. Numerous omega phases and sub-structures were induced in the alloy via the Uni-R or Bi-R process, increasing the amount of precipitation nucleation and inhibiting the coarsening of alpha phases. The strength and wear resistance of Uni-R-A and Bi-R-A samples are higher than that of the ST-A sample, revealing that pre-rolling strategies have the positive effect on microstructural refinement and performance. Compared with Bi-R process, the sub-structures formed in Uni-R process present more {332} twin characteristics, and facilitate to homogenous aging precipitation. The excellent combination performance was obtained in the Uni-R-A alloy with a highest ultimate tensile strength at 1270 MPa, and a lowest worn loss at 2.14 x 107 mu m3.