Studies on the effect of delayed aging on the mechanical behaviour of AA 6061 SiCp composite

Silicon carbide reinforced aluminium is the most notable composite in the family of discontinuously reinforced composites (DRCs). The matrix of this class of composites can be heat treated by solutionizing and aging to modify the microstructure and thereby the mechanical properties. In the present investigation the effect of delayed aging on AA 6061 SiCp composite is reported. The delay aged specimens were subjected to hardness and fatigue testing. It is observed that the mechanical properties are degraded for a delay of up to 12 h before aging. However for delay of 16 h and beyond, the properties are similar to that of composites exposed to nil (0 h) delay. The experimental results are discussed with respect to the scanning electron micrographs (SEM) of the fatigue failed samples.