Densification mechanism and microstructural evolution in selective laser sintering of Al–12Si powders

The role of processing parameters on the densification mechanism and microstructural evolution in laser sintered Al–12Si powder has been explored. It was established that both the densification mechanism and microstructural evolution in laser sintered Al–12Si powder were controlled by the specific laser energy input. Analysis of the cross-section of laser sintered microstructures of Al–12Si powders indicated that the tops of the grains in the previous layer are partially re-melted and then undergo epitaxial growth in the next layer where the heat affected zones (HAZ) grain boundaries and solidification grain boundaries (SGBs) are continuous along the fusion boundary.