Features of the strain hardening of nickel titanium in the region of thermoelastic martensite transformation

The inheritance of strain hardening in a nickel titanium (TiNi) alloy that possesses shape memory has been studied using a sample subjected to plastic deformation in the austenite state prior to a transition to the martensite state. The results show that the strain hardening created in the TiNi alloy in the austenite state is not inherited in the martensite state and the sample behaves as if there were no significant plastic deformation. It is suggested that this behavior can be related to the fact that the alloy lattice defects (primarily, dislocations generated during pre-deformation in the austenite state) are not effective obstacles to the motion of domain boundaries in the martensite state.