The influence of Ni4Ti3 precipitates orientation on two-way shape memory effect in a Ni-rich NiTi alloy

In this present work two-way shape memory effect (TWSME) induced by thermomechanical cycling treatments in a Ni-rich NiTi alloy was investigated.Effect of orientation of metastable and lenticular Ni4Ti3 precipitates as a governing parameter in different aging temperatures and time as well as applied strain on TWSME were studied. The results indicate that 450 °C is the optimum aging temperature to achieve highest recovery rate. The increasing of applied strain up to 3.38% and aging time up to 2.5 h at 450 °C improves the recovery rate. It has been concluded that formation of especial variants of Ni4Ti3 precipitates during aging and increasing of applied strain on thermomechanical cycling treatments could enhance the TWSME.