Effect of Gb on Phase Transformation and Martensitic Phase Transformation in Ni–Mn–In Alloys

Abstract

The Ni-Mn-In alloy occur martensite reverse phase transitions driven by magnetic field in a certain composition range, resulting in the macroscopic strain, and along with the output of up to 108 MPa stress. However, there are some defects impeded practical application of alloy, such as brittleness and low Curie temperature. So, we will improve its mechanical properties by doping the suitable rare earth Gd elements in Ni-Mn-In alloy in this paper.In this paper, we study the microstructure, martensitic transformation and mechanical properties of Ni45.4Mn41.5-xIn13.1Gdx (x=0,0.2,0.5,1,2) magnetic shape memory alloy by DSC and Compression fracture strength and strain curve, which clarify the influence of Gd doping on martensitic phase transformation and mechanical properties of alloys.The studies have shown that the microstructure of the alloy changes from single organization into a mixed-phase structure of the matrix and the rich-Gd phase with the increasing of rare earth Gd content and martensitic transformation temperature of the alloys increases gradually with the increasing of Gd element content; The fracture strength and fracture strain increases first and then a decreasing trend with increasing the rare earth Gd elements. The result of the improved mechanical properties is the co-action of fine grain strengthening and second phase strengthening.