Interaction of lattice dislocations with the α-γ interphase interface in a stainless steel bicrystal

The elementary mechanisms of deformation under fatigue stress are analysed in a stainless steel bicrystal by transmission electron microscopy. Attention is paid to the interaction between lattice dislocations and a ferrite-austenite interface oriented very near the Kurdjumov-Sachs orientation relationship. Results differ according to whether the notch is located in the a phase or in the g phase. Only in the bicrystal notched in the a phase was transmission of dislocations across the interface into the gamma-phase observed. A possible correlation between the microscopic observations and the fatigue behaviour of the bicrystal is discussed.