Structural and Mechanical Behavior of Al-4.4Cu/2TiB<inf>2</inf> In-Situ Nanocomposites Fabricated by Post-In-Situ Reaction Ultrasonic Processing

Al-4.4Cu/TiB2 composites were fabricated with and without post-in-situ reaction ultrasonic melt treatment. The structural and mechanical behaviors of the composites in both the as-cast (F) and T6—peak-aged conditions were analyzed and compared with the base alloy Al-4.4Cu. The microstructural result reveals that the ultrasonic-assisted processing enhanced the dispersion of nano-sized TiB2 particles. The ultrasonic treatment-assisted fabrication has improved the yield strength of Al-4.4Cu/2TiB2 composite about ~ 2 times over the monolithic Al-4.4Cu alloy in both the as-cast and peak-aged condition while retaining > 90 pct ductility of the matrix alloy. The various strengthening mechanisms operating in the materials, namely, base alloy, micro- and nanocomposite were discussed and the theoretical yield strength was estimated using appropriate equations. The theoretical yield strength estimates were found to correlate well with the experimental observations.