Scripta Materialia | 2019
Excellent superelasticity of Cu-Al-Mn-Cr shape memory single crystal obtained only through annealing cast polycrystalline alloy
Abstract
Abstract The polycrystalline Cu-13.0Al-7.7Mn-0.6Cr cast alloy consists of the Heusler L21 (Cu2AlMn) parent and the disordered body-centered cubic A2(Cr) precipitate due to bcc phase separation. These two phases are completely coherent. When annealing cast alloy, the abnormal grain growth occurs. It is closely related to the dissolution of A2(Cr) particles and the formation of a continuous misorientation gradient within the matrix grains. The results show that the single crystal close to [100] orientation shows large superelastic strain of 8.5%. Furthermore, the single crystal almost remains full superelastic characteristic after 1.2\u202f×\u202f103\u202fcycles, showing enhanced fatigue resistance.