Effects of Two Different Deformation Manners on Recovery Properties of NiTi Alloy

Abstract:

Effects of two different deformation manners, martensite reorientation (MR) and stress-induced martensitic transformation (SIM) on the tensile properties and recovery properties after pre-strain of Ni50.2Ti49.8 alloy were investigated. Results show that the strain deformed via MR is higher than that via SIM at the end of the stress plateau in the tensile deformation process. When tensile pre-strain is in the stress plateau, the two manners after the same pre-strain followed by heating have the same recovery properties; however, when the tensile pre-strain is higher than stress plateau, SIM has higher reversed transformation temperatures and recovery strain than MR after the same pre-strain followed by heating.

Key words:TiNi shape memory alloy; martensite reorientation(MR); stress-induced martensitic transformation(SIM); recovery properties