Preparation, microstructures and mechanical properties of in-situ TiB2/Al composites by mechanical stirring and subsequent ultrasonic treatment

Abstract

In this work, in situ TiB2/2024Al composites were successfully fabricated by mechanical stirring and subsequent ultrasonic treatment. The effects of reaction temperature and enhanced phase mass fraction on the microstructure and mechanical properties of TiB2/2024Al composites were studied. The results show that the reaction temperature affects the degree of reaction of the Al-Ti phase. When the reaction temperature is too low, a sheet-like Al-Ti intermediate phase still exists inside the melt. However, when the reaction temperature reaches 850 °C, the Al-Ti phase is dissolved sufficiently and evolves into TiB2 particles. The ability of TiB2 particles to refine matrix structure was also discussed. As the mass fraction of TiB2 particles increases, the matrix structure is continuously refined. When compared to the base alloy, the yield strength, tensile strength and elongation are significantly improved.