Identifying the significance of Sn addition on the tribological performance of Ti-based bulk metallic glass composites

Tailoring the properties of an engineering material with low coefficient of friction (COF) and high wear resistance has been a long goal in the tribological research. It is particularly true for the bulk metallic glass composites (BMGCs), which are promising for a large range of advanced applications. Although the materials design and mechanical properties have been extensively investigated, knowledge of their tribological behaviors is still lacking. Ball-on-block wear tests were thus conducted to investigate the effect of Sn addition on the tribological behaviors of Ti₄₅Zr₂₅Nb₆Cu₅Be₁₇ BMGCs under different normal loads. Nano-indentation and nano-scratch tests were carried out to study the phase-specific wear properties of the crystalline dendrite and amorphous matrix in BMGCs respectively. Preferred wear and delamination in the dendrite phase as a result of the plastic mismatch between the two constituent phases is responsible for the abrasive wear in the Ti₄₇Zr₂₅Nb₆Cu₅Be₁₇ and Ti₄₆Zr₂₅Nb₆Cu₅Be₁₇Sn₁ BMGCs. While, mechanically driven tribolayer during sliding enables oxidative wear and improved tribological properties in the Ti₄₅Zr₂₅Nb₆Cu₅Be₁₇Sn₂ BMGC. Based on the synergistic mechanical and chemical effects, the underlying relationship between the intrinsic dendrite properties and the wear behaviors of BMGC was revealed.