Investigation of interfacial reliability and thermal shock resistance of W/CuCrZr joints using a W–Cu functionally graded material interlayer

To address the thermal mismatch between W and CuCrZr in plasma-facing components (PFCs), the W–Cu functionally graded material (FGM) as an interlayer was incorporated into W/CuCrZr dissimilar joints through spark plasma sintering (SPS) in this study. The microstructural evolution, mechanical, and thermal performance of joints with the W–Cu FGM interlayer were systematically analyzed. Results indicate that the W/W–Cu FGM/CuCrZr joint bonded at 1000 °C exhibits strong interface bonding with the shear strength of 144.35 MPa. The compositional and thermal expansion gradients provided by the W–Cu FGM interlayer may effectively relieve thermal stress concentrations at the interface of the joints, thereby enhancing interfacial reliability and thermal shock resistance. Compared to the OFCu interlayer under the identical bonding conditions, introducing the W–Cu FGM interlayer significantly improves high-temperature thermal conductivity of the joint and maintains structural integrity after undergoing 200 thermal shock cycles at 600 °C-RT. This work confirms that the W–Cu FGM interlayer provides an effective strategy for preparing high-performance W/CuCrZr joints.