Additive manufacturing of triply periodic minimal surface (TPMS) structured dual-coated diamond/copper composites for high performance

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Additive manufactured Diamond/copper (Dia/Cu) composites are very promising candidates for advanced thermal management because of high thermal conductivity and mechanical strength. However, significant interfacial incompatibility (e.g., poor attainability, thermal expansion mismatch, and weak bonding) between diamond and Cu hinders its further high-performance application This research proposes a dual-layer surface modification strategy via integrating salt-bath titanium coating and electroless Cu plating to improve interfacial adhesion and processability of diamond particles. The continuous Ti–Cu bi-layer enhances the wettability and chemical compatibility of Dia/Cu interface for further selective laser melting (SLM) of Dia/Cu composites. The optimized SLM parameters (180 W laser power, 350 mm/s scan speed, and 0.04 mm hatch spacing) enabled the dual-layer Ti–Cu coated composites to achieve a high relative density of 95.4%. The resulting continuous Ti–Cu bi-layer coating markedly improves the chemical compatibility and wettability at the Dia/Cu interface, enabling the successful fabrication of Dia/Cu composites and complex Triply Periodic Minimal Surface (TPMS) structures via selective laser melting (SLM). additive manufacture (AM) fabricated Dia/Cu composites improved its thermal conductivity by 21.6% (from 236 to 287 W/m·K), flexural strength by 3.6% (from 270.46 to 280.18 MPa), and Vickers hardness by 11.4% (from 86.76 to 96.68 HV) compared to uncoated reference specimens. These properties enhancements are primarily attributed to the formation of a chemically bonded and thermally compatible interfacial layer, which facilitates uniform diamond dispersion and efficient energy absorption during the SLM process. This work demonstrates that integrating rational surface engineering with precision AM enables the effective fabrication of high-performance Dia/Cu composites, particularly TPMS-based architectures, offering significant potential for thermal management and structural applications requiring enhanced thermal conductivity and mechanical robustness. Flowchart of salt-bath Ti coating and electroless Cu plating