Friction and Wear Resistance of Nanostructured TiNi Shape Memory Alloy

TiNi shape memory alloys with a superelastic effect are widely used in tribological interfaces requiring high wear resistance. One of the common approaches to reducing the wear of various metals is the application of severe plastic deformation (SPD), resulting in structural refinement and corresponding hardening. This paper investigates the tribological behaviour of a nanostructured Ti49.3Ni50.7 shape memory alloy produced using SPD. The friction and wear characteristics of the alloy at room temperature are compared in the coarse-grained, nanostructured, and nanostructured aged states. Through hardness measurement and transmission electron microscopy, it is shown that the transformation of a coarse-grained state into a nanostructured state increases wear resistance and hardness, reduces the coefficient of friction, and changes the friction mechanism. Formed nanoparticles during ageing in a nanostructured state further increase wear resistance.