Effect of mechanical cutting and polishing on the shape memory transformation behavior of NiTi alloy

The results of the studies carried out on the effect of mechanical cutting and polishing on the transformation behavior of Ti-rich NiTi shape memory alloy (SMA) heat-treated at 560 and 660 °C, are presented in this article. Among the samples heat-treated at 560 °C, the sample subjected to mechanical cutting and polishing (HT560MC) shows M → A on reverse phase transformation and A → R → M on forward transformation whereas chemically etched sample (HT560CE) shows the intermediate R-phase both during forward and reverse transformations. Heat treatment at a higher temperature of 660 °C does not facilitate the formation of R-phase in the reverse transformation and helps the formation of R-phase to a very small extent, that too only in HT660MC, during forward transformation due to the reduced dislocation density. Both the heat-treated samples show the effect of mechanical cutting and polishing even at 150th thermal cycling.