DEFORMATION-INDUCED ANOMALOUS PHASE-TRANSFORMATIONS IN NANOCRYSTALLINE FCC FE-NI BASED ALLOYS

If is shown that formation of an ultrafine deformation structure is ac companied by anomalous phase transformations at 77-293 K: dissolution of disperse intermetallic Ni3Ti, Ni3Al and Ni3Zr phases in the FCC mat rix subject to cold deformation. The interaction between edge dislocat ions and the disperse phases causes an anomalous dissolution of the pa rticles as a result of the drift of atoms in the dislocation stress fi eld, while appearance of a large number of deformation vacancies leads to an equilibrium precipitation of the phases. Dissolution of the par ticles dominates under a low-temperature deformation (77 K). (C) 1997 Acta Metallurgica Inc.