The influence of β-phase plastic deformation on the martensitic transformation in Cu-Zn-Al single crystals

Abstract

Single crystals of Cu-Zn-Al alloys have been deformed in compression and in tension. Depending on the deformation temperature with respect to the transformation temperature M_s for spontaneous martensite, either martensite or plastic deformation in the β-phase, or both, are induced. Below a critical temperature M[sgrave]_s, the stress to induce 18R martensite increases linearly with increasing temperature. At M _s[sgrave] this linear curve intersects the [sgrave](T) curve for plastic deformation. Above M[sgrave]_s, plastic deformation in the β-phase precedes stress-induced martensitic transformation. The introduction of dislocations stabilizes the β-phase with respect to the martensite and shifts to higher values the critical stress to induce it. These observations are discussed and are compared with the transformation-induced plasticity behaviour in steels.