Martensitic structure of a Cu-Al-Ni alloy after a single cyclic change in the temperature and the action of reactive stresses

The martensitic transformations in a Cu-13.4 wt % Al-4.0 wt % Ni alloy subjected to a single cyclic change in the temperature in the range 293–680 K under conditions of constrained shape-memory deformation are studied by differential scanning calorimetry. These martensitic transformations are found to be closely related to the temperature dependences of the reactive stresses generated in constrained alloy samples during a single heating-cooling cycle. The substantial change in the behavior of these dependences during heating to a temperature above 600 K is caused by the strong effect of the decomposition of the β-phase solid solution on the parameters of the martensitic transformations in this alloy.