Role of Si on machined surfaces of Al- based automotive alloys under varying machining parameters

Al-based automotive alloys with different level of Si content has been conducted on the characterization of machined surfaces in terms of roughness, temperature, chips formation as well as microstructue evaluation under different machining conditions. For this experiment a shaper machine with HSS single point V-shaped cutting tool is used at different cutting speed and depth of cut. The experimental results show that the surface roughness of the alloys decresess with cutting speed and depth of cut but it is more prominent on cutting speed. It is because of  high cutting speed is more associated with the higher cutting temperatur and softening the work material leading to better surface finish. Higher Si added alloys shows the better surface finish due to formation of different intermettalics as more brittle. For brittle and higher hardness it produces the higher temperature during machining. During machining relatively curly and short chips are form by the high Si added alloy becase of its low elongation properties. Fracture surfaces of higher Si added alloy display more crack propagation obtained by the plate-like Si rich intermetallics.