Small stress-hysteresis in a nanocrystalline TiNiCuFe alloy for elastocaloric applications over wide temperature window

Shape memory alloys (SMAs) with small stress-hysteresis and wide superelasticity temperature window are highly desired for elastocaloric applications. In this study, a nanocrystalline Ti50Ni42Cu6Fe2 SMA is fabricated by casting, forging, wire-drawing and annealing. The alloy exhibits superelasticity with a narrow average stress-hysteresis of ∼180 MPa over a temperature window from 213 K to 323 K. The temperature change of the elastocaloric effect is calculated to be ∼28 K. In situ synchrotron X-ray diffraction measurements suggest that the small hysteresis is probably attributed to the enhanced lattice compatibility as quantified by the cofactor condition parameters (λ2, XI and XII). •Nanograined Ti50Ni42Cu6Fe2 SMA was fabricated by wire-drawing.•Alloy shows superelasticity from 213 K to 323 K, with 180 MPa stress-hysteresis.•Superior lattice compatibility was found by in situ synchrotron XRD.