A ductile shape memory alloy of the Ni-AI-Fe system has been developed using principles through the control of microstructure. Addition of Fe to the binary Ni-Al shape memory alloy allows the introduction of a ductile face-centered cubic (fcc) phase in an otherwise extremely brittle β phase alloy, leading to an improvement in its ductility while retaining its ability to exhibit shape memory arising from the martensitic transformation of theβ phase to Ll0 structure. It is shown that the transformation temperature in the ternary Ni-AI-Fe alloy can be easily controlled by the preannealing in the β+ γ region. Experimental results on the effect of different annealing treatments on the microstructures and the shape memory behavior in this alloy are presented and discussed.
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