Effect of cooling rate on the thermal and electrical conductivities of an A356 sand cast alloy

This study evaluates the effect of cooling rate on the microstructures and conduction properties of an A356 sand cast alloy. To evaluate effect of cooling rate, computer recordable sand mold with four step-thickness (5 mm– 20 mm) was used and microstructures of T6 heat treated specimens with different cooling rates were observed. It was found that with increasing cooling rate, eutectic reaction temperature shifted to lower temperature and the supercooling also increased. Based on the coarsening model via solute diffusion, when the cooling rate increase, secondary dendrite arm spacing decreases, providing the enhanced thermal and electrical conductivities.