Tunable Large Recovery Strain and Wide Response Temperature with Near-Zero Response Interval in Cu-Al-Mn-Fe Single Crystals

Shape memory alloys can recover the deformed shape due to their superelasticity or shape memory effect. Generally, in one shape memory alloy either the superelasticity or shape memory effect can be displayed under a certain temperature, depending on the relationship between the martensitic transformation and deformation temperature. Here we report novel Cu-Al-Mn-Fe shape memory material simultaneously showing excellent superelasticity and shape memory effect at room temperature, as well as tunably wide response temperature range with near-zero interval of reverse phase transformation by deformation. When deforming one single crystal at room temperature, it not only possesses full superelasticity of 7%, but also tunable shape memory effects up to 8.8%. The full shape recovery during heating exhibits near-zero response interval and tunably wide response temperature range of 166 K depending on the deformation. The functional characteristics of the alloys result from the controllable reverse phase transformation hinging on the stabilization of stress-induced martensite induced by completely coherent nanoparticles during deformation. This class of Cu-Al-Mn-Fe alloys may be used as both superelastic materials, and shape memory materials with wide working temperature range as high-sensitive detector, driver or sensor.