Designing a wider superelastic window

Abstract

Conventional metal alloys can only recover their original shape if subjected to very small elastic deformations. Superelastic alloys (also named pseudoelastic alloys) can recover their shape after deformations as great as 20% (1) just by unloading the force on the material. They are part of the larger group of shape-memory alloys but do not require a temperature change for recovery, and they have found applications in areas including robotics, structural engineering of buildings, and aerospace engineering (2, 3). A superelastic alloy usually exhibits this property only over a well-determined and often small temperature range normally called a “superelastic window.” On page 855 of this issue, Xia et al. (4) describe superelastic “invar” alloys with functional properties that are independent of temperature over the largest superelastic window reported, from 10 to 473 K.