Determination of the non-chemical energy terms and the equilibrium transformation temperature (T0) in CuAlNi poly- and single crystalline alloys

Results of the analysis, developed in the authorʹs group and applied in poly- and single crystalline Cu–20 at.%Al–2.2 at.%Ni–0.5 at.%B alloy, are reviewed and the dependence of the derivatives of the elastic and dissipative energy terms on the transformed fraction are presented. The T0(σ) functions (T0 is the equilibrium transformation temperature and σ is the uni-axial tensile stress, respectively), calculated on the basis of the method, by uniform heating and cooling of the specimen, are also presented. Similarly, the stress dependences of the non-chemical contributions to the phase transformation are determined. It is shown that integrals of the differential values (the derivatives of the energy contributions by the transformed fraction) give self-consistent results with the (integral) quantities directly measured in differential scanning calorimetry or obtained from the area of the hysteresis loops.