Extrinsic-Intrinsic Stacking-Fault Pairs in an Fe–Cr–Ni Alloy

Transmission electron images of extrinsic-intrinsic fault pairs in a Fe–Cr–Ni alloy are shown to be sensitive to changes in the sign of (g·b)s for reflections producing either line or stacking-fault contrast. This is interpreted in terms of the overlapping strain fields of the three closely spaced partial dislocations. A differential treatment of the measured widths of the intrinsic and extrinsic faults indicates that the stacking-fault energy ratio γe/γi=1.6 in this alloy.