Improvement of Stress Corrosion Cracking Resistance by Controlling Grain Boundary Characteristics in Cu–Al–Mn Superelastic Alloy Sheet

Abstract

The intergranular fracture rarely takes place in the polycrystalline Cu–Al–Mn shape memory alloy. This fracture mode, however, is easily induced by stress corrosion cracking. In order to overcome this problem, the grain boundary design and control were performed with various heat treatment conditions. The frequency of coincidence site lattice （CSL） boundary increased in the specimen slowly heated from α ＋ β dual–phase to β single–phase regions. The｛211｝＜011＞ recrystallization texture also developed strongly in the slowly heated specimens. On the other hand, the frequency of CSL boundary decreased and the recrystallization texture hardly developed in the rapidly heated specimen. Consequently, the suppression of intergranular fracture and the improvement of superelastic property were achieved simultaneously with a relatively simple heat treatment procedure.