Investigation of Dynamic Recrystallization of NiTi Shape Memory Alloy Subjected to Local Canning Compression

Abstract

Abstract:Physical mechanism for dynamic recrystallization of NiTi shape memory alloy subjected to local canning compression at various temperatures, 600, 700 and 800 • C, was investigated via electron backscattered diffraction experiments and transmission electron microscopy observations. With increasing deformation temperature, fractions of recrystallized grains and substructures increase, whereas fraction of deformed grains decreases. In the case of 600 and 700 • C, continuous dynamic recrystallization and discontinuous dynamic recrystallization coexist in NiTi shape memory alloy. In the case of discontinuous dynamic recrystallization, the recrystallized grains are found to be nucleated at grain boundaries and even in grain interior. The pile-up of statistically stored dislocation lays the foundation for the nucleation of the recrystallized grains during discontinuous dynamic recrystallization of NiTi shape memory alloy. Geometrically necessary dislocation plays as an important role in the formation of new recrystallized grains during continuous dynamic recrystallization of NiTi shape memory alloy.

Shape memory effect, temperature distribution and mechanical properties of friction stir welded nitinol

“…The recrystallized grains were found throughout the weld and there was no clear distinction between nugget, thermo-mechanically affected zone (TMAZ) and heat affected zone (HAZ). Generally, the dynamic recrystallization takes place in the metals when subjected to hot working and it depends upon the peak temperature, plastic strain, strain rate and stacking energy of the materials [24]. In metals with high stacking fault energy like NiTi, the continuous dynamic recrystallization occurs when the temperature is greater than 50% of the melting point [25,26].…”

Novel Research for Development of Shape Memory Alloys

“…Zhang et al studied about physical mechanism for dynamic recrystallization of NiTi shape memory alloy subjected to local canning compression at various temperatures, 600, 700, and 800 • C [22]. In the case of 600 and 700 • C, continuous dynamic recrystallization and discontinuous dynamic recrystallization coexist in NiTi shape memory alloy.…”