Multi-material additive manufacturing of steel/Al alloy by controlling the liquid/solid interface in laser beam powder bed fusion

Abstract

Laser beam powder bed fusion (L-PBF) additive manufacturing offers significant advantages in fabricating multi-material parts with complex geometries and controllable material distributions. In this study, we utilized L-PBF technology to fabricate carbon steel/Al alloy samples with specific bonding strengths by controlling the formation of intermetallic compounds at the liquid/solid interface. Machine learning was employed to optimize the process parameters for the fabrication of carbon steel and Al3Si1Mn alloy samples with minimal defects. We then investigated the interfacial mixing of dissimilar materials by varying the scanning speed, utilizing a combination of experimental and numerical simulations. Increasing the scanning speed altered the competitive relationship between the growth of different phases at the interface, suppressing the formation of coarse brittle η-Al5Fe2 and θ-Al13Fe4 intermetallic compounds. This suppression led to enhanced bonding strength at the carbon steel/Al3Si1Mn interfaces. This research presents a promising strategy for regulating phase selection in multi-material interfaces through the adjustment of additive manufacturing parameters.