Effect of Precipitation Hardening on Tensile, Fatigue and Fracture Toughness Behaviour of 8011 Al/ 15%SiCp Metal Matrix Composite

In this investigation, the effect of precipitation hardening on tensile, fatigue and fracture toughness behaviour of 8011 Al/ 15%SiCp composites has been studied. The composites were manufactured through stir casting method. Cast ingots of the composites were hot extruded at 5000 C. The composite samples were solution heat-treated at 530 0 C for 3 h and quenched in cold water. The aging temperature were 130 0 C, 150 0 C, 170 0 C, 190 0 C, and 210 0 C for aging duration of 1,3,5,7 and 9 hrs respectively. The mechanical properties measured included: tensile strength, fatigue strength and fracture toughness values. The composites produced exhibited maximum mechanical properties at peak aged condition. These increases in mechanical properties during aging are attributed to the formation of coherent and uniform distribution SiC particles in the aluminium matrix composites. It was also observed that thermal modification plays an important role in retaining the ductility of composites. This result shows that a substantial improvement in mechanical properties has been achieved in the reinforced metal matrices produced after age-hardening.