Microstructural Stability of Al3Si2.5Cu Alloy in the Semisolid State Produced via Deformation via Equal Channel Angular Pressing (ECAP)

This work aims to evaluate the thixoformability of the Al–Si–Cu alloy regarding microstructural evolution during its reheating at semisolid temperature. Low-silicon aluminum alloys are not used in casting processes but can be a viable alternative for processing in the semisolid state. In this attempt, the Al–3wt%Si–wt%2.5Cu alloy was tested. The material was produced via direct casting and then submitted to equal channel angular pressing (ECAP)—single pass. After that, for two conditions of solid fractions, 45% and 60%, globularization heat treatments were carried out for 0, 30, and 90 s. Grain size of 108 µm, globule size of 47 µm, and circularity of 0.62 were achieved, showing microstructure refinement. This demonstrates that using the ECAP process becomes an effective tool in the globularization of the microstructure and, thus, the thixoforming process. As thermodynamic and microstructural stability guarantee reasonable viscosity control and good processing control, the raw material production route via ECAP can be an excellent solution for thixoforming processes, especially for these alloys with low Silicon content.