Effect of Ferrite Second Phase on Shape Memory Effect of Corrosion‐Resistant Fe–Mn–Si Shape Memory Alloy

Abstract

At present, Fe–Mn–Si shape memory alloy with high corrosion resistance has become the focus of attention because of its special requirements in some fields. On the basis of Fe–Mn–Si shape memory alloy, a corrosion‐resistant shape memory alloy was designed by adding Cr and other alloy elements. The microstructure characteristics and phase ratio control mechanism of the annealed alloy and the influence mechanism of the second phase (ferrite) and ratio on the alloy memory effect are emphatically studied. The results show that ferrite and austenite are evenly distributed at low annealing temperature, and there is thermal‐induced ε‐martensite at the same time. Appropriate thermal‐induced ε‐martensite can strengthen the austenite matrix, and the shape recovery rate is high at this time. With the increase of annealing temperature, the volume fraction and grain size of ferrite increase, the volume fraction of thermal‐induced ε‐martensite and austenite decreases, and the shape recovery rate decreases, but it is beneficial to improve the corrosion resistance.