High-current pulsed electron beam modification on microstructure and performance of Cu/CuW diffusion bonding joints

This study investigates the influence of high-current pulsed electron beam (HCPEB) modification on the microstructure and shear strength of Cu/CuW joints. Reliable solid-state diffusion bonding of modified-Cu (M-Cu) and modified-CuW (M-CuW) was achieved by HCPEB modification pretreatment at a temperature of 800–900 °C and a pressure of 5 MPa for 10–50 min. Experiments demonstrate that HCPEB modification facilitates the dissolution of W and Cu, resulting in the formation of a Cu_0.4W_0.6 solid solution and thus enhancing the uniform distribution of microstructures. Additionally, HCPEB-induced defects play a beneficial role in promoting the diffusion process by providing fast diffusion paths for elements. The optimal joints with the maximum shear strength of 213.7 MPa were obtained through bonding M-Cu and M-CuW at 900 °C and 5 MPa for 30 min, which attributes to the combined effects of fine-grained strengthening and solid solution strengthening. Overall, the application of HCPEB modification showcases its effectiveness in promoting element diffusion and enhancing the mechanical performance of the joints.