Micro-structural and mechanical characterization of AA2014/TiB2/Al2O3 hybrid composites

In this investigation, Aluminum AA2014 alloy, Aluminum Matrix Composites (AMCs) and three Light Weight Aluminum Alloy Hybrid Composites (LWAHCs) were fabricated using powders of aluminum AA2014 alloy as matrix with Titanium-di-boride (TiB2) and Aluminum oxide (Al2O3) as reinforcements. Samples were sintered under nitrogen environment for two hours at 620°C in vacuum hot press. Influences of reinforced particles on densification, micro-structural and mechanical properties were carefully studied. Optical and SEM micrographs indicate a uniform distribution of the particles in all samples. Sintered density increases in sample-1 (aluminum AA2014 alloy) and sample-2 (AA2014+5% TiB2) and the sintered density decreases towards the LWAHCs. This is due to the pinning effect of TiB2 at grain boundary that effectively controls grain growth. For all samples, the mechanical properties increase gradually as the weigh percentage of the reinforcement particles increases. As the strength increases, the ductility of the samples is affected by the hard particles of TiB2 and Al2O3.