Influence of Sc Microalloying and Low-Frequency Electromagnetic Casting on the Microstructure and Properties of As-Rolled 7A36 Aluminum Alloy

This study examines the microstructure and properties of 7A36 aluminum alloys processed through low-frequency electromagnetic casting (LFEC) with microalloyed Sc. Following secondary hot deformation, the addition of Sc refined the average grain size from 3.8 μm to 0.9 μm and reduced the deformed texture content. In the T6-aged condition, the combined application of Sc and LFEC enhanced the hardness (234 HV to 238 HV), ultimate tensile strength (647 MPa to 693 MPa), and elongation (EL). Fractographic analysis revealed brittle fracture modes dominated by cleavage, with minor intergranular contributions. The corrosion resistance was poorest in the rolled state and superior in the two-stage-aged state. Under two-stage aging, the maximum corrosion depth for the Sc-modified, LFEC-processed alloy decreased from 113.6 to 49.1 μm. The synergistic integration of Sc alloying and LFEC significantly improved both the mechanical properties and corrosion resistance.