Development of novel tribo composites with TiNi shape memory alloy matrix

High wear resistance of a tribo composite results from its combination of reinforcing phase or particles and a flexible matrix. The former withstands the wearing force and the latter acts as a binder to retain the hard particles, to accommodate deformation and to absorb impact energy. However, it is often found that the matrix is the weaker region that leads to a decrease in the integrated wear resistance. Although great efforts have been made to enhance the wear resistance, e.g., by strengthening the matrix, the improvement is limited. This happens because a hardened matrix may have lower ductility that decreases its capability to accommodate large deformation and impact. The emergence of pseudoelastic TiNi alloy has brought the hope of overcoming this barrier. This alloy possesses high wear resistance and great flexibility, which could make TiNi alloy an ideal matrix material. Considerable efforts have been made at the University of Alberta to explore the possibility of developing novel tribo composites, employing TiNi alloy as the matrix reinforced by hard particles. This article presents a brief review of the progress in our studies on the development of TiNi matrix composites.