A comparative study on the mechanical behaviors of surface-strengthened Nitinol 60 alloy and steel

Abstract

Nitinol 60 alloy and steel were treated using supersonic fine-particle bombardment (SFPB) to improve their mechanical properties. The formation of the strengthened layer and the mechanical properties including surface roughness, hardness, and tribological properties of the untreated and treated samples were systematically investigated using surface profiler, micro-Vickers hardness, and ball-on-disk tribometer, respectively. The influences of SFPB treatment on the mechanical properties of samples are discussed. The results show that a hardened layer is formed on samples after SFPB treatment and that the treated samples exhibit high hardness and good wear resistance. It is also found that the coefficient of friction (CoF) of Nitinol 60 alloy is lowest among all the samples before and after surface treatment. The wear mechanism of the untreated sample is adhesive wear; however, the wear mechanism of the treated sample is adhesive and abrasive wear. This study will provide clear guidelines for the engineering application of Nitinol 60 alloy.