Mechanical and shape memory properties of Ni54Mn25Ga21 high-temperature shape memory alloy

The mechanical properties and shape memory effect of polycrystalline Ni54Mn25Ga21 (at.%) high-temperature shape memory alloy have been determined by measurement of the compressive stress–strain behavior at different temperatures. The Ni54Mn25Ga21 alloy possesses a martensitic transformation temperature as high as 532 K and a tetragonal martensitic structure. The critical stress increases from 190 up to 520 MPa with increasing temperature from 293 to 633 K. When the deformation temperature increases from 293 to 523 K, the obtained recovery strain corresponding to the single martensitic state reduces from 4% to 1.6%. When deformed in a mixed state with martensite and parent phase at 538 K, it exhibits a shape recovery strain of 1.6%. Furthermore, an incomplete pseudoelasticity has been observed when deformed in the parent phase at 633 K.