Effects of crystallographic orientation on the superelastic response of Mg–Sc single crystals

Mg–Sc shape memory alloys (SMAs) have attracted scientific interest as promising lightweight multifunctional materials because of their quite low density (∼2 g/cm3). To date, few studies have investigated the correlation between superelasticity (SE) and crystallographic orientation in this alloy. In the present work, the effects of crystallographic orientation on the superelastic response of single-crystalline Mg–19.1Sc SMAs along the ⟨310⟩, ⟨101⟩, and ⟨232⟩ directions were systematically investigated. It was shown that the ⟨101⟩ orientation exhibited a superelastic strain of approximately 7.1% at 153 K, larger than that of the ⟨310⟩ orientation (6.4%) and ⟨232⟩ orientation (5.0%). Moreover, the slope of critical stress–temperature curve for the ⟨101⟩ orientation was 0.44 MPa/K within the temperature range of 153–273 K, smaller than that of 0.56 MPa/K for the ⟨310⟩ orientation from 153 to 233 K and 0.55 MPa/K for ⟨232⟩ orientation from 153 to 253 K. The orientation dependence of the superelastic strain and C–C slope may be attributed to the difference in martensite variants and theoretical superelastic strains, respectively.