Morphology evolution and growth mechanism of TiB₂ in Ti-54Al-curcive greek chiB alloys

Microstructure and phase constitution of Ti-54Al-(0.8-1.7)B (atomic fraction, %) alloys produced by an in situ growing method were investigated by XRD and SEM respectively. The results show that these alloys are composed of TiAl and TiB₂ phase. TiB₂ phase dispersed in TiAl matrix in the morphologies of convoluted flakes, plates, needles and particles. There are some very thin convex flakes growing on {1010}faces of TiB₂ and some pyramidal protrusion or rod shape dendrites on (0001) face of TiB₂, which have the same orientation as the primary TiB₂. The morphology evolution and growth mechanism of TiB₂ were analyzed according to TiB₂ crystal structure and growth condition.