Cu-Mn-Ga-based full superelasticity single crystals with low stress hysteresis and high critical stress for inducing martensite

In this study, novel Cu-Mn-Ga-based (Cu-13Mn-6Ga-8Al-xMo, x = 0.5, 0.8, 1.0, wt. %) full superelasticity single crystals with great combination properties of low stress hysteresis, high critical stress, and full superelasticity were prepared for the first time. The results show that these single crystals consist of L21(1) austenite and A2(Mo) phase before and after annealing. The A2(Mo) phase increases with the increment of Mo content. Three single crystals with orientations close to [314], [415], and [236] all exhibit full superelasticity while applying large prestrains, even being up to 10 % in Cu-13Mn-6Ga-8Al-1.0Mo single crystal. More importantly, the superelasticity behaviors show high critical stress for inducing martensite (up to 723 MPa in Cu-13Mn-6Ga-8Al-1.0Mo single crystal) and low stress hysteresis (about 30 similar to 60 MPa). From the point of strength and functional characteristics, the Cu-13Mn-6Ga-8Al-xMo single crystals can be used as a new driving material.