Characterization of hybrid lattice structures fabricated by laser powder bed fusion and casting processes by Bragg edge neutron imaging

According to ISO/ASTM TR 52912, multimaterials are defined as parts or components fabricated using more than one material. Among the various multimaterial combinations investigated, those involving Cu-based or Al-based alloys with Ni-based superalloys or steels are particularly attractive. These combinations merge the high strength and corrosion resistance of Ni-based alloys or steels with the superior electrical and thermal conductivity of Cu and Al alloys. The development of hybrid lattice structures that combine laser powder bed fusion (LPBF) with casting techniques presents a promising strategy to tailor material properties for advanced applications. LPBF enables the fabrication of high-strength lattice frameworks using alloys optimized for mechanical performance, while casting allows the integration of materials with lower melting points and better thermal/electrical conductivity. This hybrid approach leverages the design flexibility of additive manufacturing with the bulk property benefits of cast metals, an ideal combination for aerospace, automotive, and energy applications. In this study, hybrid lattice structures composed of Inconel 718/CuCrZr and AISI 316L/Al10SiMg were fabricated using this combined manufacturing approach. Inconel 718 and AISI 316L lattice frameworks were first produced by LPBF, and the grid structures were subsequently filled with CuCrZr or Al10SiMg powders melted using different casting processes. The present work focuses on the characterization of the microstructure and the residual strain associated with the manufacturing process in these multimaterial combinations. The analysis was performed using Bragg edge neutron imaging at POLDI (Pulse OverLap DIffractometer), the time-of-flight diffractometer at SINQ, Switzerland.