Wear Behavior and Microstructure of Selective Laser Melting Additive Manufactured Hypereutectic Al-Si Alloys

In this study, the hypereutectic Al- Si alloys were fabricated using selective laser melting (SLM) at several laser powers from a mixture of eutectic Al-12% Si and pure Si powders. The effect of laser power on microstructure, microhardness and wear behavior of Al-Si alloys were investigated with a focus on size, morphology and distribution of Si particles in SLM processed part. The highest relative density and microhardness of SLM-processed Al-Si alloys were presented at the parts obtained at laser power of about 210 W. The microstructure of Al-Si alloys was determined using Optical microscope (OM) and scanning electron microscope (SEM). The results show that the laser power has an important influence on the microstructure of SLM-processed parts, such as, the grain size and morphology of Si. The Energy-dispersive X-ray spectroscopy (EDS) results indicate that the low laser power samples show lower Si content than that of the high laser power samples. Dry sliding wear test and Vicker microhardness measurement were employed to characterize the mechanical properties of the as-processed Al-Si alloys. Moreover, the wear behaviors of as-processed samples were compared with that of conventional produced hypereutectic Al-Si parts.