INSITU TRANSMISSION ELECTRON-MICROSCOPY OBSERVATION OF THE PHASE-TRANSITION IN THIN-FILMS OF THE AL-MN SYSTEM

Al-Mn thin films were produced by evaporation of the Al1-xMnx alloys, with x = 0.10, 0.14, 0.20, 0.25 and 0.32, on NaCl substrates held at e ither liquid-N2 temperature or room temperature. The thin films obtain ed showed an almost amorphous structure. When these films were heated in situ in the transmission electron microscope, several phases of the Al-Mn system were observed during the amorphous-to-crystalline transi tion process produced. The structural evolution observed depends on th e chemical composition and the thickness of the film. Some of these ph ases were Al6Mn, Al3Mn, Al4Mn, Al11Mn4, Al8Mn5, AlMn and quasi-crystal line phases. On comparison of our results with the Al-Mn phase diagram , it is concluded that this diagram does not reproduce completely the situation for thin films.