Effect of Sb on physical properties and microstructures of laser nano/amorphous-composite film

A nano/amorphous-composite film was fabricated by laser cladding (LC) of the Co–Ti–B4C–Sb mixed powders on a TA15 alloy. Such film mainly consisted of Ti–Al, Co–Ti, Co–Sb intermetallics, TiC, TiB2, TiB, and the amorphous phases. Experimental results indicated that the crystal systems of TiB2 (hexagonal)/TiC (cubic) and Sb (rhombohedral) played important role on the formation of such film. Due to the mismatch of these crystals systems and mutual immiscibility of the metallic components, Sb was not incorporated in TiB2/TiC, but formed separate nuclei during the film growth. Thus, the growth of TiB2/TiC was stopped by the Sb nucleus in such LC molten pool, so as to form the nanoscale particles.