HVEM IN SITU OBSERVATION OF EARLY STAGE OF MARTENSITE FORMATION IN Cu-Zn ALLOYS

The early stages of bcc to 9R martensitic transformation in Cu-Zn alloys have been observed in situ by a high voltage electron microscope in order to establish whether if the habit plane of the martensite in the nucleation stage is different from that of the fully grown one as predicated by the Olson-Cohen nucleation model. The results are in contradition to their model, indicating that the invariant plane strain condition on the habit plane is operating from the very beginning of the martensitic transformation