Microstructure, superelasticity and shape memory effect by stress-induced martensite stabilization in Cu-Al-Mn-Ti shape memory alloys

摘要

In this study, the microstructure, martensitic transformation, superelasticity, stabilization of stress-induce martensite and the corresponding shape memory effect of Ti-doped Cu-Al-Mn shape memory alloys were investigated. The results show that the present Cu-Al-Mn-Ti alloys consist of two types of L2(1) phases, including Cu2AlMn parent and Cu2TiAl precipitate. The dispersive L2(1)-Cu2TiAl precipitates strengthen the stabilization of stress-induced 2H(gamma'(1)) martensite from L2(1)-Cu2AlMn parent. Thus, all studied alloys show not only superelasticity at deformation, but also shape memory effect after unloading by heating. Consequently, the Cu-12.9Al-8.3Mn-0.5Ti alloy (wt%) possesses the best superelastic strain up to 4.6% and a shape memory effect of 1.5% under a pre-deformation of 11%, while Cu-12.8Al-7.7Mn-2.6Ti alloy (wt%) shows the best shape memory effect up to 2,5% simultaneously showing 1.9% of superelastic strain with a pre-deformation of 10%.