PLASTIC-DEFORMATION OF CUALMN SHAPE-MEMORY ALLOYS

CuAlMn alloys transforming below room temperature were cold rolled after quenching up to 93% reduction. Alloys deformed only 10% were already completely martensitic and did not show reverse transformation to beta(1) upon heating. With increasing deformation, refinement-of martensitic plates occurred due to repeated internal twinning and injection of new orientation variants. This was accompanied by decreasing size of ordered domains down to that of short-range ordered microdomains at 93% reduction. Deformation bands appearing at 60% reduction consisted of extremely small grains, giving an electron diffraction pattern resembling that of an amorphous structure.