ROLE OF ATOMIC PROBE TECHNIQUES IN THE IN VESTIGATION OF PHASE-TRANSFORMATION

The role of both Field Ion Microscopy and Atom-Probe techniques in the investigation of solid state phase transformations is discussed on th e basis of some examples. The first illustration deals with Long Perio d Superstructures observed in Cu3 Pd system. Atom-probe investigations conducted on (001) planes show the occurence of Long Range Order modu lations in the vicinity of antiphase boundaries. Because of its very h igh spatial resolution, atom-probe is also an attractive tool for the study of unmixing processes. Some results related to the spinodal deco mposition of the iron-chromium system are discussed in connection with current unmixing theories. Prospects opened by the emergence of new t hree-dimensional atom-probes are given.