Influence of process parameters on microstructure and interfacial mechanical properties of Al6061/AlSi10Mg multi-material components fabricated via laser powder bed fusion

Advanced manufacturing has evolved in recent years through the synergistic integration of additive manufacturing (AM) with conventional methods to enable the creation of high-performance components with complex features. In this study, AlSi10Mg powder was printed on extruded Al6061-T6 substrate blocks using Laser Powder Bed Fusion (LPBF). An orthogonal L16 Taguchi experiment was designed where the laser power, scanning speed, and hatching distance of the first ten layers of the interface were varied to examine their isolated effect on the bonding quality of multi-material structures. This interfacial bond quality was evaluated through Iosipescu shear testing and various characterization techniques. Laser power was found to be the principal factor influencing defect morphology: lack of fusion (LOF) voids, keyhole pores, and crack formation; followed by Linear Energy Density (LED). A maximum average interfacial shear strength of 178.54 ± 5.49 MPa was achieved by the bimetallic parts, close to that of AlSi10Mg. Moreover, an inverse correlation was observed between shear strength and the porosity percentage in the fusion region. The AlSi10Mg region exhibited the highest microhardness (109.56 ± 0.5 HV), while Al6061 had the lowest (98.20 ± 1.26 HV), and the interface showed intermediate values (99.35 ± 1.03 HV). • Effect of laser parameters on interfacial properties of multi-material parts is investigated. • Independently, LED and VED are insufficient indicators of defect morphology. • The significance of laser power in determining defect morphology is observed. • Hatch spacing is a critical parameter controlling interfacial shear strength. • Interfacial shear strength correlates inversely with porosity at the interface.