Effects of plate thickness on reverse martensitic transformation of prestrained NiTi/NiTi alloy

Abstract

In this paper, differential scanning calorimeter (DSC) was used to study the effects of predeformation and plate thickness on the reverse martensitic transformation of explosively welded NiTi/NiTi alloy. Results showed that there was a constraint between Ni_50.4Ti (NiTi-1) and Ni_49.8Ti (NiTi-2), which led to that the thickness of NiTi-1 or NiTi-2 strongly affected the reverse martensitic transformation behavior because residual stress variations in thickness wound enable bias force to be built inside the composite. The DSC measurements showed that after deformation, the reverse martensitic transformation temperature of the composite was increased with the increasing thickness of NiTi-2. Also, the XRD results revealed that the microstructure of NiTi/NiTi alloy changed from B2 phase to B19  phase along the thickness direction.

Keywords

NiTi, explosive welding, martensitic transformation, internal stress