Nature of the intermetallic Al8Si6Mg3Fe in the AK7ch alloy microalloyed by the Ti-B-Sr complex

Objective. The aim of the study is to determine the chemical composition, structure, and peculiarities of the formation of the iron-containing intermetallic Al8Si6Mg3Fe in the AK7ch alloy under the combined effect of Ti-B-Sr microalloying and thermal treatment of the melt. Methodology. The object of the study was the AK7ch alloy microalloyed with a Ti-B-Sr complex after temperature-time melt treatment under various regimes. The Al8Si6Mg3Fe intermetallic was studied using metallographic analysis, local X-ray spectral analysis, and differential scanning calorimetry. Results. The chemical composition of the iron-containing intermetallic Al8Si6Mg3Fe was determined, its morphology was studied, and the temperature dependence of its volume fraction in the AK7ch (Ti-B-Sr) alloy as a function of temperature-time melt treatment was established. The reason for the reduction in the volume fraction of Al8Si6Mg3Fe was identified. Scientific novelty. A reduction in the amount of the iron-containing intermetallic phase Al8Si6Mg3Fe in the AK7ch alloy containing the Ti-B-Sr complex was observed after temperature-time melt treatment at 800°C. Practical significance. The reduction of the negative impact of iron due to the formation of a smaller amount of the intermetallic compound Al8Si6Mg3Fe in the structure of the AK7ch alloy containing the Ti-B-Sr complex, after temperature-time melt treatment at 800°C, simultaneously improved the strength, plasticity, and corrosion resistance of the alloy.