Strengthened solid solution and homogenized eutectic structure of Al-based multi-component alloy via electromagnetic stirring

Macro-segregation and coarse intermetallic compounds (IMCs) are common problems in lightweight multi-component alloys (MCAs), in this work, electromagnetic stirring treatment (EST) and mixed eutectic strategy were proposed to tune the solidified microstructure of Al-based MCA. For the studied MCA, the positive and negative segregation of solute elements (except for Si) were found both lower than 5 % in the ingot, and the macro-segregation was reduced by approximately 50 % after the EST utilized. Also, the dispersion of the fine eutectic β-Mg ₂ Si phase was significantly promoted by applying EST, specifically, its size at the edge of the ingot was ranged in 2–4 μm. Consequently, the alloy prepared by EST present superior strength-plasticity synergy at room temperature (RT), with the ultimate compressive strength reaching 724 MPa at the edge of the ingot and the strain reaching 15.1 % at the center of the ingot. Moreover, EST was determined enhance the content of solid-solutioned Al atoms in the eutectic β-phase, thus varied its crystal structure and reduced its hardness and Young`s modulus, and futher enhanced the deformation coordination between the IMCs and the matrix, thereby improving the mechanical properties of the alloy. This study elaborated the underlying mechanism of microstructural homogeneity regulation, the obtained results could offer guidance for fabricating large-sized Al-based MCAs with excellent mechanical properties.