Simultaneous improvement of ductility and shape memory effect of two-phase Ni53Mn22Co6Ga19 high-temperature shape memory alloy with the addition of Ta

► Small Ta addition results in the refinement of grain size, which can simultaneously improve the ductility and shape memory effect of two-phase Ni53Mn22Co6Ga19 alloy. ► The best tensile ductility and shape memory effect are 11% and 3.3% with Ta = 0.2 at.%. ► The ordered γ′ phase is present at Ta = 0.4 at.%, and it tends to wrap γ phase and segregates martensite and γ phase.