Microstructural evolution and mechanical properties of in situ TiB_2/Al composites under high-intensity ultrasound

摘要

Microstructural evolution and mechanical properties of in situ TiB2/Al composites fabricated with exothermic reaction process under high-intensity ultrasound produced by the magnetostrictive transducer were investigated. In this method, the microstructure and grain refining performance of the TiB2/Al composites were characterized by optical morphology(OM), scanning electron microscopy(SEM), energy-dispersive spectrometer(EDS), and X-ray diffraction(XRD) analysis.Microstructural observations show a decreasing trend in the grain size of the composites due to the ultrasound and the content of TiB2 particles in the composites. Compared with the process without ultrasound, the morphology and agglomeration of TiB2 particles are improved by high-intensity ultrasound. Meanwhile, it is proposed that the formation of TiB2 particles occurs via the transformation from Ti Al3, and at the optimal amount of the reactants, the conversion efficiency of Ti Al3 into TiB2 almost reaches up to 100 %. Finally, the effects of high-intensity ultrasound and TiB2 particles on the mechanical properties of the TiB2/Al composites were also discussed.