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(MCu) and modified-CuW(M-CuW) was achieved by HCPEB modification pretreatment at a temperature of 800-900 ℃ 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 Cu0.4W0.6solid 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℃ 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.