Synergistic enhancement of thermal conductivity and mechanical properties of selective laser melting AlSi10Mg alloys via aging treatment

Abstract Selective laser melting (SLM) offers considerable potential for fabricating thin-walled radiators because of its capability to produce lightweight components with complex structures. Among candidate materials, the AlSi10Mg alloy is particularly well suited for additive manufacturing (AM) due to its excellent processability. However, the rapid solidification inherent to the AM process leads to forming a supersaturated solid solution in the AlSi10Mg matrix, which markedly reduces its thermal conductivity. In this study, an aging heat treatment was employed to promote the precipitation of solute phases from the supersaturated solid solution, thereby enhancing the thermal conductivity and mechanical properties of the AlSi10Mg alloy. The results indicate that aging at 200 °C for 10 h effectively promotes the precipitation of Si particles within the α-Al matrix. This treatment yields a notable tensile strength of 350 MPa and a high thermal conductivity of 173.70 W·m⁻ 1 ·K⁻ 1 , representing a 44.3% improvement over the as-built state. Thus, we achieved a synergistic enhancement of both thermal and mechanical properties. The improved thermal conductivity is attributed to reduction of solid-solution Si in the matrix and the refinement of precipitated Si particles. These findings provide both theoretical insights and technical guidance for fabricating high-performance aluminum alloy heat sinks via AM, with promising applications in aerospace and electronic cooling systems.