EFFECT OF SENSE OF LOADING ON MARTENSITIC TRANSFORMATIONS IN CU-AL-NI SINGLE-CRYSTALS

Stress and temperature induced martensitic transformations have been investigated in the shape memory alloy Cu-14.2Al-4.1Ni. Thermal cycles, and tensile and compression deformation tests were performed. The results are presented in the form of non-equilibrium sigma-T phase diagrams and the effect of the sense of loading is discussed. From the experimental non-equilibrium data the equilibrium sigma-T phase diagrams were derived. The asymmetry between the sigma-T diagrams for tension and compression can be qualitatively explained on the basis of the Clausius-Clapeyron equation.