Effect of permanent magnetic field positioning on microstructure and mechanical properties of casted Al-Cu alloy

Abstract

This study presents a novel investigation into the role of permanent magnetic field positioning and penetration in modifying the solidification behavior, microstructure, and mechanical properties of Al-10Cu alloys, a crucial material for high-performance applications. Compared to conventional casting, applying a magnetic field alters fluid flow, solute distribution, and grain morphology, significantly enhancing material properties. Five magnetic configurations were analyzed: 0–0 (no field), 1–0, 2–0, 1–1, and 2–2. The results reveal that the 2–2 configuration, where the mould cavity is sandwiched between two pairs of permanent magnets, yields the highest grain refinement (47.3 µm), improved solute distribution, and reduced segregation, as confirmed by SEM-EDS analysis. This configuration also exhibits the highest mechanical strength, with a yield strength of 180.17 MPa, ultimate tensile strength of 264.70 MPa, and hardness of 33.67 HRC, an increase of 31 % in UTS and a 21 % reduction in grain size compared to the conventional casting process. Fractographic analysis indicates that the improved ductility in the 2–2 configuration results from finer grains and enhanced grain boundary strengthening, consistent with the Hall-Petch relationship. This study uniquely demonstrates that magnetic field penetration on microstructure and assisted solidification offers a novel approach to optimizing microstructure and mechanical properties, making it highly suitable for automotive, aerospace, and shipbuilding applications.