A CoCrFeNiMnSi High Entropy Alloy Showing a Good Combination of Shape Memory Effect and Mechanical Properties

We realized a good combination of shape memory effect and mechanical properties in a hot-rolled Fe47.7Mn15.5Co9.8Cr10.8Ni5.1Si11.1 high entropy alloy (HEA) by Si alloying and proper heat treatment to guarantee a low density of annealing twin boundaries. Its maximal recovery strain of 5.7% reached the level that conventional FeMnSi-based and Co-based shape memory alloys (SMAs) showing the same FCC to HCP martensitic transformation can realize. It showed a better combination of ultimate tensile strength and fracture strain than the reported CoCrFeNiMn-based HEAs with FCC matrix did. This result showed that to marry the shape memory effect with the excellent mechanical properties will be a promising direction for developing novel HEAs.