The Influence of Bismuth, Antimony, and Strontium on Microstructure, Thermal, and Machinability of Aluminum-Silicon Alloy

In this article, the influence of separate additions of bismuth, antimony, and strontium on microstructure, thermal, and machinability of Al-11%Si-2%Cu alloy (ADC12) has been reported. Additives depressed the aluminum-silicon eutectic growth temperature (T-G) and altered the silicon morphology. Different silicon morphologies, namely flake, lamellar, and fibrous influenced the main cutting force, feed force, and surface roughness during turning. Workpieces with fibrous silicon morphology produced the highest cutting force, feed force, and surface roughness while that of bismuth-containing workpieces produced the lowest cutting force, feed force, and the best surface roughness due to the formation of bismuth compound which acts as lubricant during turning. The results showed that the highest T-G is related to the best surface roughness and as such the best machinable alloy investigated.