On the preparation and mechanical properties of in situ small-sized TiB₂/Al-4.5Cu composites via ultrasound assisted RD method

In situ small-sized TiB₂/Al-4.5Cu composites with high strength and good ductility were prepared via an ultrasound assisted re-melting and diluting (RD) approach in this research. The experimental results showed that small-sized TiB₂ particles with an average size of 100 nm were synthesized in the metal-salts reaction. Both the Al-TiB₂ mater composite and TiB₂/Al-4.5Cu composites with homogeneous microstructures were obtained due to the effects of ultrasound. The α-Al grains in Al-4.5Cu alloy transferred from large-sized dendrite to small-sized spherical in morphology by adding the TiB₂ particles. Compared with the original Al-4.5Cu alloy, the 5 wt% TiB₂/Al-4.5Cu composites exhibited the best comprehensive mechanical properties, and the yield strength, ultimate tensile strength and elongation were improved by 39.7%, 39.9%, and 7.9%, respectively. Furthermore, the mechanisms of the improved mechanical properties, including the strength and ductility, of the composites were discussed.