A Review on Melt Treatment of Al-Si Cast Alloys: Sources of Porosity | ||
| International Journal of Materials Technology and Innovation | ||
| Articles in Press, Accepted Manuscript, Available Online from 14 October 2025 | ||
| Document Type: Review Article | ||
| DOI: 10.21608/ijmti.2025.422980.1130 | ||
| Authors | ||
| Herbert W. Doty1; Mohamed A. Moustafa2; Agnes M. Samuel3; Hany R. Ammar4; Fawzy Samuel* 5 | ||
| 1Materials Technology, General Motors Global Technology Center, Warren, MI, USA | ||
| 2Materials Technology, CMRDI | ||
| 3UQAC | ||
| 4Mechanical Engineering Department, College of Engineering, Qassim University, Saudi Arabia | ||
| 54555 Av Coronation | ||
| Abstract | ||
| Porosity formation in Al-(7-11) %Si cast alloys was analyzed in terms of (i) concentration of hydrogen in the liquid metal, (ii) addition Sr as eutectic Si modifier, (iii) grain refining using (Al-5%Ti-1%B, and Al-4%B master alloys) and P as primary Si refiner, (iv) volume fraction of Al2Cu and β-platelets, (v) rare earth metals, (vi) solidification rate in the range of dendrite arm spacing of 23-95 µm, (vi) effect of porosity content on the alloy tensile and impact properties. Hydrogen content is approximately four times more effective as porosity formation element than the addition of ~150 ppm Sr. Grain refiner particles and phosphorus result is a significant reduction in the percentage of porosity, The β- platelets (Al5FeSi intermetallic phase) are active sites of pore nucleation. Both β-platelets and A12Cu phase particles restrict growth of the precipitated pores Increasing the local solidification time or the solidus velocity increases the pore parameters. Analysis of porosity was carried out using Field Emission Electron Microscopy. | ||
| Keywords | ||
| Gas porosity; Shrinkage porosity; Hydrogen content; Melt treatment | ||
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