Effect of Multiple Martensitic Transformations on Structure of Fe-Ni Alloys

摘要

Effect of multiple direct and reverse martensitic transformations on fragmentation of austenitic grains in Fe-Ni alloys have been studied by X-ray diffraction and scanning electron microscopy.An ultra-fine structure was formed by fragmentation inside austenitic grains due to progressing misorientation of austenitic sub-grains during multipleγ-α-γ-martensitic phase transitions.An increase in the number ofγ-α-γ-transformations increases misorientation angle between austenitic sub-grains and leads to transformation of an austenitic single crystal into a textured polycrystal.It has been shown that multipleγ-α-γ-martensitic phase transitions change the mechanism of internal stress relaxation from dislocation-based to deformation twinning.