Regulating the Lüders-like bands by selected-area shot peening in NiTi alloy

Abstract

In this paper, a novel method to regulate the position, initiation and propagation angle of the Lüders-like bands (LDBs) in NiTi alloy was proposed by the selected-area shot peening. The influence of the selected-area shot peening on the elastocaloric cooling effect of NiTi alloy, as well as the corresponding relationship between deformation of the LDBs at different angles and crystallographic texture, were investigated. The results demonstrated that the selected-area shot peening can not only regulate the position of the LDBs formation, but also keep their initiation and propagation angle within a certain range. The corresponding relationship between the macroscopic formation angle (θ = 60°) of the LDBs and the microscopic crystallographic texture was established. This method is advantageous for realizing gradient phase transformation, thereby enabling gradient cooling, and holds promising application prospects in the field of elastocaloric cooling.