Tribology Properties of Titanium‐based Metals Reinforced by BN Nanosheets

Herein, the tribology properties of titanium matrix composites (TMCs) are studied, which are formed by simply blending of aspherical Ti particles and BN nanosheets (BNNSs) using low-energy ball milling and then spark plasma sintering. The mechanical properties of TMCs are characterized by nanoindentation tests, and their friction and wear properties are determined by ball-on-disc tests. The results show that the TMC with 0.1 vol% BNNSs (0.1-TMC) content has the highest hardness and the ratio of hardness to elastic modulus (H/E). In addition, the lowest coefficient of friction (COF) and wear loss of 0.1-TMC indicate the best tribological performance. Analysis of the worn morphology reveals that the pure Ti with the lowest H/E value presents several microcracks on the surface, implying the microcutting dominates wear process. The addition of BNNSs effectively inhibits the formation of microcracks, thus improves the tribological properties. However, as the content increase, the adhesion of BNNSs and Ti powder becomes worse, increasing the wear debris, leading to abrasive wear and adhesive wear and causing the even more severe wear. As a result, the COF and wear loss of 0.8-TMC are the largest.