Generation and relaxation of reactive stresses in Cu-Al-Ni shape-memory alloy

Reactive stresses in Cu-Al-Ni shape-memory single crystals are experimentally determined on constrained samples heated at a constant rate in the temperature range 293–800 K. At temperatures up to 600 K, the stresses increase with temperature. At higher temperatures, they begin to decrease as a result of the decomposition of the β-phase and vanish at 800 K. The theory of diffuse martensitic transformation is used to calculate the reactive stresses, including the case when the volume fraction of the β-phase decreases, at temperatures above 600 K.