(001) FAULTS IN 40-AT-PERCENT-AL-0.7-AT-PERCENT-C-0.5-AT-PERCENT-B

The nature of planar defects in a quaternary Fe-40 at.% Al-0.5 at.% B- 0.7 at.% C alloy has been investigated using diffraction contrast anal ysis in a transmission electron microscope and via Z-contrast electron microscopy. From diffraction analysis, it is confirmed that the fring e contrast observed is due to complex planar faults on {100} planes wi th displacement vectors 1/2 [100] lying in the fault plane. This concl usion is verified by direct observation of the faults using Z-contrast microscopy. In addition to the 1/2[100] in-plane shift, there is also an aluminium layer missing at the fault. These complex faults also di splay antiphase-boundary contrast when examined using a superlattice r eflection.