THERMOMECHANICAL COUPLINGS AND PSEUDOELASTICITY OF SHAPE-MEMORY ALLOYS

Energy balances of a polycrystalline CuZnAl Shape Memory Alloy are per formed using infrared and calorimetric techniques. The experiments und erline the main role of temperature variations induced by deformation process on the stress-strain curves. A thermodynamic analysis shows va riations essentially due to the latent heat of phase change and indica tes a very small intrinsic dissipated energy compared with deformation work or latent heat. Oil the basis of these results, a behaviour mode l that takes account of thermomechanical couplings is proposed. Implem ented in a finite elements code, this model is used to verify the cons istency and the potentialities of such an approach by means of numeric al experiments. (C) 1998 Elsevier Science Ltd. All rights reserved.