Influence of grain refinement and modification on dry sliding wear behaviour of Al–7Si and Al–7Si–2.5Cu cast alloys

The microstructures and dry sliding wear behaviour of Al–7Si and Al–7Si–2.5Cu cast alloys were studied after various melt treatments like grain refinement and modification. Results indicate that combined grain refined and modified Al–7Si–2.5Cu cast alloys have microstructures consisting of uniformly distributed α-Al grains, interdendritic network of fine eutectic Al–silicon and fine CuAl2 particles in the interdendritic region. These alloys exhibited improved wear resistance in as cast condition when compared with those of alloys in untreated or modified conditions. This paper attempts to investigate the microstructures and sliding wear behaviour of the cast Al–7Si and Al–7Si–2.5Cu alloys by addition of either grain refiner or modifier and also by addition of both these.