shape memory,property possessed by certain alloysalloy
[O. Fr.,=combine], substance with metallic properties that consists of a metal fused with one or more metals or nonmetals. Alloys may be a homogeneous solid solution, a heterogeneous mixture of tiny crystals, a true chemical compound, or a mixture of these.
..... Click the link for more information. that allows them to return, when heated, to their original shape after having been deformed. This effect results because, as the alloy is deformed, it undergoes a martensitic (or athermal) transformation—a solid-state transition that rapidly changes the crystalline structure of the alloy without thermal activation—that is readily reversed once an appropriate amount of heat is applied. Among the alloys are copper-aluminum-nickel, copper-zinc-aluminum, nickel-titanium, and iron-manganese-silicon. Applications of shape memory include heat-activated fasteners, switches, eyeglass frames, orthopedic devices, teeth braces, and blood clot filters.
Changing shape from a rigid form to an elastic state when thermal energy is applied is called shape memory. When the thermal stimulus is removed, the material reverts back to its original rigid state without degradation, which is called superelasticity. See also: Smart materials