X-RAY-DIFFRACTION EFFECTS GIVEN BY THE AUSTENITIC PHASE DURING THE TRAINING PROCESS OF SHAPE-MEMORY CU-ZN-AL POLYCRYSTALS

To visualize the grain boundary role on the shape memory property of C u-Zn-Al alloy, we have followed the austenitic structure evolution, of crystals submitted to a training treatment, by synchrotron X-ray topo graphy in white beam. Single crystals, tricrystals and polycrystalline samples have been studied. The comparison of results shows that in po lycrystalline samples large, non recoverable stresses, develop in all grains. These stresses must be taken into account when the origin of t he shape memory property is discussed.