Growth morphology and mechanism of MC carbide under quasi-rapid solidification conditions

The growth morphology and mechanism of a MC carbide (TiC type) under quasi-rapid solidification conditions of laser surface alloyed coatings on a titantium aluminide alloy are studied. The MC carbide under quasi-rapid solidification conditions with a cooling rate of about (4×10²) °C /s is found to have an unique dendritic morphology having strong faceted and brick-stacking growth characteristics on dendrite arms. The growth mechanism is a brick-stacking/double-zigzag micro-branching mechanism originating from lateral growth on the intersecting {111} planes.