Aging behavior of a 2024 Al alloy-SiCp composite

In the present research work the 2024 aluminum alloy was reinforced with SiC particles via powder metallurgy method. The effect of heat treatment conditions on artificial aging kinetics was investigated. The solution treatment of the composite sample and the unreinforced alloy was carried out at 495 °C for 1, 2 and 3 h followed by aging at 191 °C for various aging times between 1 and 10 h. The existence of SiC particles led to increasing the peak hardness of the alloy. The peak hardness of the composite sample took place at shorter times than that of the unreinforced alloy for the samples solution treated for 2 and 3 h, but took place at longer times for the samples solution treated for 1 h. The suitable solution treating time was about 2 h for both the composite and the unreinforced alloy that led to the fastest aging kinetics and the maximum hardness. At the solution treating time shorter than 2 h due to incomplete dissolution of precipitates, the aging kinetics decelerated and the hardness values decreased. X-ray diffraction studies indicated the presence of precipitation phases such as CuAl2 and CuMgAl2 in the composite in both as-extruded and solutionized conditions. For the samples solution treated more than 2 h, hardness values decreased due to the grain growth of matrix but no change occurred in the aging kinetics.