A Novel Training‐Free Cast FeMnSiCrNi Shape Memory Alloy Based on Formation of Martensite in a Domain‐Specific Manner

Abstract The proposed key to producing a good shape memory effect in FeMnSi alloys is to reduce or even prevent the collisions between martensite bands. A method for realizing this is to make stress‐induced martensite bands form in a domain‐specific manner. We developed a novel training‐free cast Fe18Mn5.5Si9.5Cr4Ni alloy with residual lathy delta ferrite based on this idea. The recovery strain reached 6.4% only after annealing the cast Fe18Mn5.5Si9.5Cr4Ni alloy. Microstructure observations indicated that the lathy delta ferrite made the stress‐induced martensite form in a domain‐specific manner by first subdividing grains into smaller domains. We hypothesize that through adjusting alloy compositions, solidification parameters, and heat treatment technique, the shape recovery of cast FeMnSi alloys can be further improved. Such a finding will provide a novel method for developing training‐free FeMnSi shape memory alloys.