Effect of Mg and trace elements on the solidification and dissolution of Al2Cu phase in 319-type alloys | ||
| International Journal of Materials Technology and Innovation | ||
| Articles in Press, Accepted Manuscript, Available Online from 13 September 2025 | ||
| Document Type: Original Article | ||
| DOI: 10.21608/ijmti.2025.416524.1129 | ||
| Authors | ||
| Fawzy Samuel* 1; Herbert W. Doty2; Agnes M. Samuel1; Victor M. Songmene3 | ||
| 1Universite du Quebec a Chicoutimi, Saguenay, Quebec, Canada | ||
| 2Materials Technology, General Motors Global Technology Center, Warren, MI, USA | ||
| 3Department of Mechanical Engineering, École de Technologie Supérieure, Montreal, QC H3C 1K3, Canada | ||
| Abstract | ||
| Grain refining plays an important role in reducing the degree of the Al2Cu segregation. Increasing the Mg content results in transformation of some of the Al5FeSi into Al8Mg3FeSi6, as well as precipitation of Al5Mg8Cu2Si6 in the form of branched crystals or ultrafine eutectic, growing out of Al2Cu particles during the complex eutectic reaction that takes place in the final stages of solidification. Increasing the Mg content gradually reduces the temperature of the incipient melting. The presence of trace elements such as Fe and Ni in the base alloy and their interactions with the Mg and Cu forming insoluble compounds may increase the onset temperature of incipient melting. Both experimental, industrial and the Mg level of the alloy determine required heat treatment to produce the optimum tensile properties. As for the two-stage solution treatment, it is recommended that the second stage solution temperature should not exceed 520 ºC, in particular for high Mg content i.e., 0.6%. Compared to the experimental alloys, the industrial alloy shows better resistance to the incipient melting due to the reaction between Cu and trace elements mainly Fe and Ni present in the industrial alloy. Solutioizing at 520 °C for 8h resulted in ultimate tensile strength (UTS) of 400 MPa whereas solutionizing at 535 °C for the period yielded only UTS value of 150 MPa due to the occurrence of incipient melting. | ||
| Keywords | ||
| Al2Cu; incipient melting; solution heat treatment; microstructure | ||
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