The β→αTransformation in Poly crystalline SiC: III, The Thickening of α Plates

摘要: The final stages of the β→α polymorphic phase transformation in conventionally sintered and hot-pressed SiC were studied by optical transmission electron microscopy. interface between α β regions partially transformed grains invariably contains thin lamellae adjacent parallel to coherent twins (or stacking faults). These planar defects serve as nucleation sites for transformation, with growth occurring motion partial dislocations nucleated at intersection incoherent twin boundaries. Various structural phenomena SiC, including faulting, mi-crosyntaxy, long-period polytypism, are discussed terms this mechanism.