Abstract
The motivation to replace steel and cast iron with Al-Si alloys in automotive components stems from an on-going attempt to improve fuel economy and reduce emissions. In the light of these objectives, a study was carried out to determine the influence of metallurgical parameters such as chemical composition, microstructure and morphology of second phase particles formed in 396 type near-eutectic Al-Si cast alloys containing ~11% Si, on their machinability. The results show that the Mg-free alloy displays only a slight increase in the drilling force, moment, and power with the progress of drilling, while in comparison, the Mg-containing base alloy shows a rapid increase in these same parameters. The Mg-free alloy produces the highest number of holes, followed by the alloys containing 0.3% Mg, and 0.6% Mg, respectively. The chip breakability of the alloys containing the Al2Cu phase is superior to that of the alloys containing Mg2Si.