Effect of Ni Interlayer on the Microstructure and Mechanical Properties of SiCp/316L-Cu Heterogeneous Laminated Composites

Fabricating heterogeneous laminated structures by combining the 316 L stainless steel (with high strength) and the copper (Cu, with superior thermal conductivity) represents an effective approach to achieve materials with exceptional comprehensive properties. To address interfacial bonding challenges between 316 L and Cu, a nickel (Ni) interlayer was introduced via spark plasma sintering (SPS), producing two architectures: Silicon carbide particle reinforced 316 L(SiCp/316 L)-Cu and SiCp/316L-Ni-Cu heterogeneous laminated structures. The effects of the Ni interlayer on microstructure, thermal properties, and mechanical performance were systematically investigated. Results indicated that no elemental diffusion occurred at direct SiCp/316L-Cu interfaces. In contrast, mutual diffusion of Ni-Cu and Ni-316L interfaces established superior metallurgical bonding. The incorporation of Cu significantly improved thermal conductivity (an increase of 120.65 W/(m·K) compared to pure 316 L), while the Ni interlayer further elevated thermal conduction in SiCp/316L-Ni-Cu by establishing uninterrupted heat-transfer pathways. Moreover, the yield strength of SiCp/316L-Ni-Cu increased by 52.15% compared to SiCp/316L-Cu, attributed to load-bearing and stress-transfer mechanisms facilitated by the Ni-bonded interfaces. Compared with monolithic SiCp/316 L, the SiCp/316L-Ni-Cu heterostructure demonstrated simultaneous improvements in strength and ductility, owing to heterogeneous grain size distribution, property mismatch between layers, and interfacial crack-arresting effects.