Direct observation of domain structures and interface dislocations in M7C3by high-resolution electron microscopy

Abstract

The domain and defect structures of M7C3 with a lattice parameter ratio b/a not-equal square-root 3 in a cast-iron based superalloy have been studied by transmission electron microscopy. High-resolution (HR) images viewed along the exact [001] beam direction have displayed domains with threefold rotational symmetry and interface dislocations which lie on the prismatic plane of the hexagonal sublattice. The antiphase boundaries on (110) planes have also been detected in the [111] HR images.