In situ study by synchrotron X-ray diffraction of the motion of basal stacking faults during the reverse-phase transformation of a Cu-Zn-Al single crystal

The reverse 9R --> beta transformation of a Cu-Zn-Al single crystal is foll owed 'in situ' by synchrotron X-ray topography and X-ray diffraction. From the modifications of the diffraction spots observed in Laue diagrams near t he transition temperature, the motion and the elimination of basal stacking faults is described. This structural evolution of the crystal in the marte nsitic phase can be considered as a precursor stage to the 9R --> beta tran sformation. (C) 1999 Elsevier Science S.A. All rights reserved.