Laser Powder Bed Fusion of Diamond-Reinforced AlSi10Mg: Printing Process, Interfacial Characterization, and Mechanical Properties

Abstract

The additive manufacturing of metal matrix composites (MMCs) using laser powder bed fusion (LPBF) is gaining considerable attention for its ability to produce high-performance materials with intricate geometries. However, incorporating reinforcement such as diamond (D) particles poses challenges to the melting and solidification behavior of the powders, potentially affecting print quality. In this study, the laser irradiation of AlSi10Mg powder mixed with 5 vol% of uncoated D particles is investigated across varying processing parameters. Dense (97%) and crack-free parts are successfully produced using high laser powers (300 and 400 W) and low laser scanning speeds (300 and 400 mm s⁻¹). It is shown that the energy needed for proper melting of the powder surpasses that required for printing pure AlSi10Mg. Scanning transmission electron microscopy coupled with energy-dispersive X-ray spectroscopy uncovers a direct interfacial reaction between the molten aluminum (Al) and the D reinforcement, forming Al carbide at the Al–D interface. Moreover, Al composites processed under optimal energy density exhibit an enhanced Young's modulus. It is highlighted that optimizing LPBF processing parameters is crucial to achieve superior material properties in MMCs, while controlled matrix–reinforcement interactions offer the potential for tailored properties.