Martensite reversion in an Fe-21%Mn-0.1%C alloy

X-ray diffraction (XRD) measurements were employed to study the martensite reversion in an Fe-21%Mn-0.1%C (wt.) alloy with an initial fully martensitic structure (epsilon + 2% alpha) induced by cold rolling. The samples were mounted in a high temperature XRD camera and were subjected to heat treatments of 1.2 x 10(3) s at increasing temperatures (step 50 K) from 373 to 773 K. So, after each heating step, it was possible to collect high precision XRD line profiles from the same zone. Traces of gamma phase appear after the heating at 573 K, and after 723 K the transformation is completed. The newly formed gamma phase has a high density of stacking faults and several relief steps appear on the surface of previously mirror-like polished samples. The surface morphology was examined by optical, scanning electron and scanning tunnelling microscopy. The results indicate that the epsilon --> gamma transformation is a martensitic transformation taking place by faulting mechanism. (C) 1999 Elsevier Science S.A. All rights reserved.