This study aims to develop defect- and crack-free Copper-Inconel 718 (Cu-In718) bimetallic structures using laser-directed energy deposition (LDED) with the objective of establishing a reliable approach for producing components that combine adequate thermal and superior mechanical performance for aerospace and thermal management applications.
In the present study, cladding of In718 with a thickness of 6 mm is deposited on a cylindrical Cu substrate (40 mm diameter) using the LDED process by optimizing laser power, scan speed and powder feed rate to mitigate interfacial defects arising from copper’s high thermal conductivity and reflectivity. Furthermore, microstructural examination using electron microscopy attached with energy-dispersive spectroscopy, hardness testing, micro-tensile analysis and thermophysical characterization was performed to assess metallurgical bonding, mechanical integrity and thermo-mechanical performance.
The interface exhibited intermixed columnar and cellular dendritic grains, with approximately 100 µm Cu diffusion into the In718 matrix and limited Ni and Fe diffusion toward the Cu side. Hardness measurements indicated a steep transition from 64 ± 3 HV (Cu) to 311 ± 9 HV (In718). The parallel bimetallic configuration achieved a tensile strength of 831 ± 37 MPa with 0.34 strain, outperforming the series configuration and confirming interface soundness. Thermophysical analysis revealed a relative density above 99.3%, thermal conductivity between 25.8 and 53.5 W/m·K and thermal diffusivity in the range of 7.8–13.8 mm²/s, demonstrating property bridging between both constituents.
The work presents, to the best of the authors’ knowledge, one of the first systematic demonstrations of LDED-based fabrication of Cu–In718 bimetallic structures with validated metallurgical bonding, structural integrity and functional thermophysical response. The findings highlight LDED as a practical route to manufacture high-performance Cu-In718 multi-material components for demanding environments requiring simultaneous mechanical strength and heat transfer efficiency.
