Abstract
This study investigates the mechanical properties and tribological performance of hybrid additive manufactured aluminum alloys produced by laser powder bed fusion on an AA6061 preform. Two combinations, AlSi10Mg/AA6061 (S10) and AlSi7Mg/AA6061 (S7), were methodically assessed regarding microstructure, microhardness, tensile properties, and wear resistance. Microstructural investigation demonstrated a metallurgically bonded interface including a progressive compositional gradient, facilitating efficient load transfer across the joint. The microhardness profile revealed a gradient from the additively built region to the preform substrate, with S10 demonstrating superior hardness (136.6) relative to S7 (121.9), hence validating the strengthening influence of elevated Si content. Tensile tests revealed that rupture consistently occurred in the AA 6061 specimen rather than at the interface, indicating enhanced interfacial integrity. Tribological studies indicated a consistent coefficient of friction of around 0.532 for S10 and approximately 0.552 for S7 after the running-in regime. The wear rate of S10 (0.0028 mm³/N·m) was significantly lower than that of S7 (0.0032 mm³/N·m). Three-dimensional profilometry indicated a considerable decrease in surface roughness and wear depth for S10 (Sa = 125 nm; depth = 654 nm) relative to S7 (Sa = 278 nm; depth = 1153 nm). The enhanced wear resistance of S10 is due to increased microstructural hardening and less asperity interaction, which mitigate abrasive and delamination wear mechanisms. The findings indicate that augmenting silicon concentration in hybrid additively manufactured aluminum alloys markedly improves mechanical performance and wear resistance while preserving strong interface bonding.