Molting and resolidification of a subcooled mixed powder bed with moving Gaussian heat source

Melting of a subcooled powder bed that contains a mixture of two powders wi th significantly different melting points under a moving Gaussian heat sour ce was investigated numerically. Shrinkage induced by the density change on the melting process was taken into account in the physical model. The prob lem is formulated using a temperature transforming model and solved by the finite difference method. The results show that the effect of surface heat loss due to convection and radiation is not negligible regardless of whethe r the shrinkage phenomena is considered. The decrease of moving heat source intensity will result in decrease of the sintering depth and the volume of the liquid pool. The increase of the scanning velocity will decrease the s intering depth and the location and shape of the liquid pool is affected si gnificantly.