Evolution behavior of TiB2 particles during laser welding on aluminum metal matrix composites reinforced with particles

The evolution behavior of TiB2 particles was studied during laser welding on aluminum metal matrix composites (MMCs) reinforced with TiB2 particles by a high power laser. X-ray diffractometry (XRD), scanning electron microscopy (SEM) and energy spectrum analysis (EDS) were used to analyze the phase, thermodynamics and morphology characteristics of the particles in the weld seam, and the interface reactions between TiB2 particles and aluminum matrix were also discussed. The results show that partial TiB2 particles melt and merge into larger ones in the middle of the weld seam and that fracture can be found in larger particles when the scale of TiB2 cluster is larger than the spot size of laser. Al3Ti and AlB12 are produced by the interface reaction between TiB2 particles and Al matrix. The interface reaction of broken TiB2 particles in the middle of the weld seam is stronger than that at the edge of the weld seam.