Manufacturing A206 Aluminum Alloy by Step Sand Casting: Effect of Solidification Time on Mechanical and Surface Properties of the Cast Samples Using Experimental and Simulation Results

摘要

In the present study, the effect of solidification time on the grain size, mechanical properties, hardness, static contact angle, and corrosion resistance of A206-T7 aluminum alloy was investigated. To study the effect of solidification time, a step sand casting, with varying section thickness, was made. Microstructural analysis was performed using optical microscopy images, and morphology and elemental composition of the samples were studied via scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) analysis, respectively. Contact angle (CA) measurements were performed on the fully polished specimens using a goniometer. Potentiodynamic polarization experiment was performed to study the corrosion resistance of the samples. The casting process was also simulated by use of a commercial software. The conclusion drawn from the simulation process shows that larger thickness allows for higher solidification time. The experimental results for the physical properties of the samples are consistent with the process simulation results. The experimental results indicate that by increasing casting thickness, the average grain size increases from 80 to 124 μm. Wetting study shows that CA values range between 71° and 87°. Corrosion experiment reveals a correlation between solidification time and corrosion resistance of the A206 samples. It was found that the corrosion current nearly decreases by 73% when section thickness increases from 0.75 to 2 in. indicating that the dominant corrosion mechanism in this alloy is presumably intergranular corrosion.