The Effect Of The Interaction Between Pouring Time, Pouring Temperature And Mould Temperature On The Filling Characteristics, Solidification Kinetics, Microstructural Evolution, And Mechanical Properties Of A356 Aluminium Alloy: A Simulation Study And Exp

Abstract

The A356 aluminium alloy (Al-7Si-0.3Mg) is widely used in automotive and aerospace components due to its high strength-to-weight ratio and good castability; however, its final properties are highly dependent on the casting process parameters employed. This study aims to evaluate the effect of the interaction between pouring time, pouring temperature and mould temperature on the filling behaviour, solidification kinetics, microstructural evolution and mechanical properties of the A356 alloy using a computational fluid dynamics (CFD) simulation approach validated by experiments. A Taguchi L9 experimental design with three factors and three levels was used to arrange nine combinations of pouring time (5, 8, 11 seconds), pouring temperature (700, 720, 740 °C) and mould temperature (200, 250, 300 °C) in the gravity casting process. Simulations of filling and solidification were carried out using the volume-of-fluid (VOF) and enthalpy-porosity models to predict flow patterns, local cooling rates and potential defect locations, whilst experimental validation included measurements of the actual cooling curve, secondary dendrite arm spacing (SDAS), eutectic silicon morphology, and tensile testing under both as-cast conditions and following T6 heat treatment. The results show that an increase in pouring temperature prolongs the solidification time and increases the SDAS, whilst an increase in mould temperature significantly reduces the cooling rate, thereby coarsening the dendritic structure and the eutectic Si particles. A combination of a pouring time of 8 seconds, a pouring temperature of 700 °C, and a mould temperature of 200 °C yielded optimum mechanical properties, with a tensile strength (UTS) of 231 MPa, a yield strength of 129 MPa, and an elongation of 7.1%. ANOVA analysis showed that mould temperature contributed most significantly to the variation in response (34.2%), followed by pouring temperature (28.7%) and pouring time (11.4%), with a significant interaction between pouring temperature and mould temperature on SDAS and UTS. The novelty of this research lies in the integration of three-dimensional filling-solidification simulation with the analysis of the interaction of three factors simultaneously, which was validated through microstructural data and mechanical properties.