Individual and Combined Effects of Reinforcements on Fractured Surface of Artificially Aged Al6061 Hybrid Composites

Abstract

The present work mainly focuses on a comparative study of the individual and combined effect of reinforcements on tensile strength and fracture surface analysis of Al6061 alloy and its composites during artificial aging. SiC and B4C are the two reinforcements used in the present work for the preparation of Al6061 composites by the stir casting process, and the reinforcement percentage from 2, 4, and 6 wt.% varied. Both Al6061 alloy and its composites are solution-treated at 558 °C/2 h and artificially aged at 100 and 200 °C for different time intervals to achieve peak aging. The results show substantial improvement in ultimate tensile strength during low temperature aging at 100 °C. Approximately 80–110% increase in UTS value is observed in both individual and hybrid composites compared to Al6061 alloy. The mechanism of failure governing the tensile strength for both alloy and its composites is thoroughly analyzed and discussed using a scanning electron microscope. The morphology of crack propagation is also studied to determine the mechanism of failure. Al6061 alloy shows ductile failure due to coarser dimples. Al6061-SiC composites show particle-matrix interface cracking and shear failure. Al6061-B4C composites show elongated dimple rupture mode of failure, whereas Al6061-SiC + B4C hybrid composites fail due to nucleation growth and mixed fracture mode.

Synergistic effects of cold rolling and age hardening on the hardness and tensile characteristics of AA6061 hybrid composites

“…Additionally, the increase in wt% of SiO 2 particles showed an increase in the hardness of the hybrid composite. This can be attributed to the increase in the existence of harder dispersoids that positively influences the hardness of the composites [32,33]. Figure 7 shows the Brinell hardness values of the three different regions on as cast AA6061 and AA6061 hybrid composites.…”

Comparative Study on Mechanical Property and Fracture Behavior of Age-Hardened LM4 Monolithic Composites Reinforced with TiB2 and Si3N4

“…In the instance of LM4, the dimple density was higher, but there were also micro-voids and some river patterns, indicating that the sample had undergone ductile failure. One of the key causes for the brittle mode of fracture and the highest UTS value in peak-aged L3TB sample is due to the existence of hard reinforcements and the formation of metastable intermetallic phases during HT [40].…”