Microstructure, mechanical properties and heat resistance of AL30 piston alloy produced via electromagnetic casting

The paper explores the microstructure, mechanical properties and heat resistance of the piston alloy AL30 (AK12MMgN) for the first time produced via continuous casting into an electromagnetic mold (electromagnetic casting, EMC). The study demonstrates that casting into EMC allows for the formation of a homogeneous dispersed microstructure in both the peripheral and central zones of the ingot, consisting of a blend of aluminum's solid solution and eutectic, which contains lamellar silicon (Si). The volume fraction of compact primary Si particles does not exceed 1 %. In addition to Si, the aluminum matrix contains the phases of crystallization origin such as e-Al₃Ni, p-Al₈FeMg₃Si₆, Q-Al₄Cu₂MgSi₇ and S-Al₂CuMg. The analysis of the evolution of microstructure and properties of a cast alloy after conventional heat treatment (HT) reveals that microstructural changes induced by HT lead to the AL30 alloy having mechanical properties that far exceed the properties of its counterparts obtained through traditional casting methods. The research analysis shows that mechanical properties and heat resistance of the AL30 alloy produced via EMC with subsequent T6 treatment are comparable to the deformable piston alloys such as the AK12D alloy after similar heat treatment.