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

Yanqiu Zhang,Li Hu,Shuyong Jiang

doi:10.3390/met7060208

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.

Highlights

NiTi-based shape memory alloys (SMAs) have been widely used in the engineering fields because they possess shape memory effect as well as superelasticity [1,2]
It can be generally accepted that DRX has an influence on the microstructures of metallic alloys, which further have an effect on the mechanical properties [10,11]
It is important to investigate the DRX mechanisms of metallic alloys subjected to plastic deformation at high temperatures

Summary

Introduction

NiTi-based shape memory alloys (SMAs) have been widely used in the engineering fields because they possess shape memory effect as well as superelasticity [1,2]. It is well known that plastic deformation at high temperatures is of great importance in manufacturing the products of. Dynamic recrystallization (DRX) frequently occurs during plastic deformation of NiTi-based SMAs at high temperatures [6,7,8,9]. It can be generally accepted that DRX has an influence on the microstructures of metallic alloys, which further have an effect on the mechanical properties [10,11]. It is important to investigate the DRX mechanisms of metallic alloys subjected to plastic deformation at high temperatures. Many researchers have devoted themselves to investigating the DRX of various metals subjected to uniaxial compression at high temperatures [12,13,14,15,16,17]. Only a few literatures related to the DRX of NiTi-based

Methods

Results

Conclusion