TRAINING PROCESS OF CU-ZN-AL SINGLE-CRYSTALS STUDIED BY SYNCHROTRON X-RAY TOPOGRAPHY

The structure evolutions of Cu-Zn-Al single crystals submitted to ther mal cycling, with or without external stress applied during the transf ormation, have been followed in situ and in real time by synchrotron X -ray topography. This original method, based on x-ray diffraction, bri ngs information on crystallographic relations between the two phases, on defect distribution and on stresses resulting from the transformati on. The comparison of results has permitted to underline the differenc es in crystal structure evolutions (with or without stress applied) an d to approach the origin of the shape memory effect.