Composite powder consolidation using selective laser melting: Input energy/porosity morphology/balling effect relation

In this study AlSi10 Mg/Al₂O₃ composite was processed via selective laser melting. The influence of different process parameters namely, laser power, scan speed and hatch spacing was investigated to determine their effect on the physical and mechanical properties of the consolidated powders. Input energy and balling effect, had a major influence on the developed pore morphology. Poor consolidation associated with poor heat diffusion and insufficient melting occurred at the low input energy. Intermediate input energy resulted in the formation of continuous porosity along the building direction separated by consolidated zones of equal width and associated with uniform balling effect. High input energy developed distorted porosity with non-uniform distribution associated with irregular course balling. The formed continuous porosity is attributed to the segregation and migration of alumina particles to the spacing between the deposited successive powder layers followed by their selective melting forming oxide films that acts as a barrier to the complete solidification.