Effects of crystallographic orientation on the superelastic response of FeMnAlNi single crystals

Abstract

The effects of crystal orientation on the tensile superelastic response of the Fe43.5Mn34Al15Ni7.5 single crystalline shape memory alloy, oriented along the <100> and <123> directions were investigated. The single crystals aged at 200°C for 3h demonstrated superelastic strains of 3.6% along the <100> orientation and 7.8% along the <123> orientation. Although the theoretical transformation strain in the <100> orientation is higher than that in the <123> orientation, the <123> oriented single crystals demonstrate better superelastic recovery in tension due to a higher number of active martensite variants, which promote better accommodation of internal strains and help minimize defect formation during transformation.