Tensile fractography of artificially aged Al6061-B4C composites
Presence of various amount of B4C reinforcement (2, 4 & 6% wt.) in Al6061 alloy on the hardness and tensile behaviour is studied in the present work. The influence of artificial aging due to presence of reinforcement on Al6061 alloy also evaluated. Brinell hardness and failure behaviour during tensile loading which impact the growth of failure physiognomies have been confirmed. The conventional age hardening treatment at three aging temperatures (100, 150 and 200°C) is performed on the composites, peak hardness and ultimate tensile strength variations at three aging temperatures is critically analysed. Lower temperature aging shows enhancement of hardness by 170% and ultimate tensile strength by 90%. The best results obtained during peak aging at 100°C is subjected to transmission electron microscope (TEM) analysis to look into the type of intermetallic responsible to strain the matrix alloy. TEM study recognises the Mg2Si phase formation during peak aging. Precipitation of this intermetallic phase and presence of harder reinforcements leads to the enhancement of hardness and nucleation of void growth failure during artificial aging treatment.