Thermoelastic martensitic transformation has been studied in CuAl(11.5 wt%)Ni(5.0 wt%) single crystalline
shape memory alloy under constant temperature, T, as well as under constant uniaxial stress, s,
measuring the relative deformation, e, as the function of s and T, respectively. From the obtained
hysteretic curves the stress/temperature dependence of the martensite and austenite start and finish
temperatures/stresses were calculated and discussed in terms of chemical and non chemical energy
contributions. The difference between the slopes of the start and finish temperatures versus stress
functions and the slope of the equilibrium transformation temperature versus stress is interpreted as the
consequence of the s dependence of the elastic energy term. The transformation strain e
tr depends both
on s (at constant T) and on T (at constant s) and both functions have the same saturation value, belonging
to the stress induced (single) variant martensite structure. It was obtained that the dissipative terms are
practically independent of s and T, and have higher values for the 3wT than for the 3ws loops |
