1985 年 26 巻 12 号 p. 861-868
An attempt was made to observe in situ early stages of the isothermal martensite formation by a high voltage electron microscope, using Fe–Ni–Mn and Fe–Ni–Mn–C alloys. Observed transformation characteristics are different, in many respects, from those in bulk specimens, but some experimental facts which characterize the isothermal martensitic transformation have been obtained; especially, an observation of the generation of dislocations prior to the martensite nucleation provides direct evidence supporting a rate controlling mechanism proposed by Kajiwara for the isothermal martensitic transformation. It is considered that, in the case of the fcc/bcc (or bct) martensitic transformation, observation of the nucleation stage in thin foil experiments is intrinsically impossible due to the small thickness of specimens even on very favorable experimental conditions.
