The Al6061 alloy matrix materials exhibiting excellent mechanical properties with the addition of SiC and B4C particulates as reinforcement. Liquid Metallurgy route is preferred for preparing composite specimen materials. Composites were subjected to heat treatment process followed by quenching in castor oil. Then all the specimens are subjected to artificial aging at a temperature of 120˚C for different time duration. Using Rockwell hardness testing machine, hardness properties are examined for the composite materials before and after heat treatment. It is observed that Al6061 metal matrix composite experimented under identical heat treatment conditions shows a considerable increase in hardness.