Unidirectional axial solidification experiments of cast aluminium alloys, AlZn5Mg1-Fe1.2 and AlSi7Mg0.3 alloys (w%) – prediction of transient mushy zone temperature field

Net-shaped casting processes in the automotive industry have proved difficult to simulate due to the complexities of the interactions among thermal, fluid, and solute transport regimes in the solidifying domain. The existing casting simulation software lacks the necessary real-time estimation of the transient thermal field of the mushy zone during solidification, a critical input to the solidifying domain thermal resistance in a casting process, for solving the temperature in the solidifying domain. To address the shortcomings, an axial directional solidification experiment (ASE) setup was developed to map the thermal data as the melt solidifies unidirectionally from the chill surface under unsteady-state conditions. Dilute Eutectic Cast Aluminium (DECA) alloy, Al-5Zn–1Mg–1.2Fe–0.07Ti and without Titanium, Eutectic Cast Aluminium (ECA) alloy, Al–7Si–0.3Mg–0.2Ti, were used to generate transient thermal data from the controlled ASE experiments. The thermal data were parsed in the 2-phase solid liquid (mushy) domain with non-dimensional time (τ), temperature (θ) and total time for mushy zone solidification for 12 thermocouple locations, to predict the temperature field in the mushy zone domain using a multi-variable non-linear regression model. The results demonstrate the reliability of the axial solidification experiment apparatus in accurately providing input to the casting simulation software and would aid in casting numerical simulation models.