Optimization of cooling slope casting parameters and reheating process for semi-solid ADC12 aluminum alloy feedstock

Abstract

This study investigates the optimization of cooling slope (CS) casting parameters and reheating conditions for semi-solid ADC12 aluminum alloy feedstock to achieve refined microstructures and improved formability. ADC12, a hypoeutectic Al–Si–Cu alloy widely used in automotive applications, was cast using a water-cooled SS400 steel CS at angles of 30°, 45°, and 60°, with pouring temperatures of 585 °C, 595 °C, 605 °C, and 615 °C. The as-cast billets were reheated at 580 °C for holding times between 40 and 80 min to promote spheroidization of primary α-Al grains. Microstructural characterization was conducted using optical microscopy, and grain size and sphericity were quantified via ImageJ and statistically analyzed using the Weibull distribution in OriginPro. Results showed that a slope angle of 45° with a pouring temperature of 595 °C, followed by reheating at 580 °C for 80 min, produced fine, highly spherical α-Al grains with uniform distribution and minimal porosity. Compared with other tested conditions, this combination demonstrated superior microstructural stability, which is expected to enhance rheological behavior and mechanical integrity during subsequent semi-solid forming. The optimized parameters have direct applicability in producing high-quality ADC12 components for the automotive industry, reducing defects, and improving dimensional precision.