Stacking fault energy, thermal expansion behavior, and elastic coefficients of a single-crystalline CrFeNi medium-entropy alloy

The equiatomic CrFeNi alloy is considered to be a model single-phase face-centered cubic medium-entropy alloy. The Bridgman technique was employed to grow a single crystal of this alloy and its dilatation behavior and elastic properties were measured in the temperature range: 100 K–673 K. Based on transmission electron microscopy investigations, plastic deformation is initially caused by the glide of dissociated dislocations (Shockley pairs bounded by a stacking fault ribbon). From their dissociated widths, a stacking fault energy of 36 mJ∙m-2 was determined.