Abstract: Selective laser melting (SLM), a laser-powder bed fusion (L-PBF) additive manufacturing technique, demonstrates significant potential for enhancing the mechanical performance of Al-Si alloys. In this study, three representative hypoeutectic Al-Si alloys (AlSi7Mg, AlSi10Mg, and AlSi12) were fabricated via SLM additive manufacturing to systematically investigate the influence of silicon content on microstructural evolution and mechanical properties. Advanced characterization techniques including scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), and transmission electron microscopy (TEM) were employed to systematically examine the cavitation erosion behavior of additive-manufactured Al-Si (AM Al-Si) alloys. The experimental findings reveal that varying silicon content predominantly alters the morphology and dimensions of the silicon network structure in AM Al-Si alloys, particularly through modulation of cellular silicon wall thickness. This microstructural modification was identified as the primary determinant in enhancing cavitation erosion (CE) resistance, with the refined silicon network architecture effectively impeding crack propagation and phase boundary delamination under CE conditions.

Key words: Cavitation erosion, Al-Si alloys, Additive manufacturing