Alumina loss mechanism of Al2O3-AlSi10 Mg composites during selective laser melting

Al2O3-AlSi10 Mg composites samples were fabricated by selective laser melting. The alumina loss phenomenon was observed by optical microscope (OM), X-ray diffraction (XRD) and energy dispersive spectrometry (EDS). As the scanning speed and hatch spacing decreases, i.e., the input laser energy increases, the loss rate of Al2O3 increases, which tendency is the same as the relative density of the SLMed samples versus process parameters. The loss mechanism of alumina was analyzed theoretically and experimentally. The loss mechanism of alumina is found that the aluminum acts as a reducing agent, causing the Al2O3 becoming a gaseous substance Al2O during the SLM process. The higher the input laser energy, the higher the temperature of the molten pool, the higher the loss rate of Al2O3. •Al2O3 loss phenomenon occurs during the SLMed Al2O3-AlSi10Mg composite.•The Al2O3 loss is closely related to the process parameters.•The main loss mechanism of Al2O3 is the reduction reaction of Al2O3 by aluminum.