Compressive response of nickel-rich NiTiHf high-temperature shape memory single crystals along the [1 1 1] orientation

The shape memory properties of Ni-rich NiTiHf single crystals along the [1 1 1] orientation were investigated by thermal cycling under constant stress and stress cycling at constant temperature in compression. The single crystals demonstrate stable shape memory behavior under ultrahigh stress levels (1000 MPa) with about 3% transformation strain, a maximum work output of 30 J cm−3 and nearly perfect pseudoelasticity at high temperatures (180–200 °C).