Plastic deformation of single crystals of the heusler alloy Cu2MnAl

Abstract

This paper reports the results of the first detailed study of the room temperature mechanical behavior of a ternary ordered alloy. Single crystals of Cu2MnAl were tested in both free and plane-strain compression. Optical and transmission electron microscopy results established that the slip mode is {110} 〈111〉. The superlattice dislocations consist of two 1/2a 0 〈111⦔ partials separated by an APB of unsually high energy, unlike the case of isostructural Fe3Al. The initial work hardening rate θ in free compression varies from 78 MN/m2 for the single slip orientation to ∼1100 MN/m2 for [100] and [111] where multiple slip occurs. For plane-strain compression, the τ-γ curves are divided into two bands, depending on the stability of the orientation during deformation. Thus the Taylor model which predicts a single band is disobeyed. The work hardening results are interpreted in terms of strong latent hardening in Cu2MnAl.