Superelasticity of different-orientated Cu–Al–Ni-based austenite single crystals.

In this study, the Cu–Al–Ni based shape memory austenite single crystal (Cu-13.5Al–4Ni–6Fe–4Mn) with two different orientations were prepared for the first time through simply annealing cast alloy. The single crystal contains the L2 1 matrix and rich-Fe nanoprecipitates with two structures (D0 3 and A2). The martensitic transformation temperatures and chemical compositions of two different-oriented single crystals are very close. Two different-oriented single crystals both possess complete superelasticity when deforming from 3% to 8%. The critical stress of stress-induced martensite for the [2–75] single crystal is about 500 MPa, which is more than twice that of the [−401] single crystal. The [−401] single crystal has much better cycle stability, in which it can maintain stable and prefect superelasticity during 500 cycles without fracture. [Display omitted] • Centimeter-scale Cu–Al–Ni–Fe–Mn austenite single crystals are obtained by annealing as-cast alloys. • Both of the two single crystals with different orientations possess a fully strain recovery of 8%. • When a pre-strain of 6% is applied, the single crystal still does not fracture after 500 cycles of compression. [ABSTRACT FROM AUTHOR]