Effect of Ni content in Cu_(1-x)Ni_(x) coating on microstructure evolution and mechanical properties of W/Mo joint via low-temperature diffusion bonding

摘要

The 93 W and Mo1 refractory metals were bonded with different Cu_(1-x)Ni_(x) coating interlayers of various Ni content using plasma-activated sintering at 700℃.The effects of the Ni content in the Cu_(1-x)Ni_(x) coating interlayer on the interfacial microstructure evolution and mechanical properties of the W/Mo joints were studied.The maximum average shear strength of the W/Mo joint was 316.5 MPa when the Ni content of the Cu_(1-x)Ni_(x) coating interlayer was 25%.When the Ni content of the Cu_(1-x)Ni_(x) coating interlayer was below 50%,the atomic diffusion at the W/Mo joint interface was adequate without the formation of intermetallic compounds,as demonstrated by the High Resolution Transmission Electron Microscope analyses of the joints.The presence of Ni in Cu_(1-x)Ni_(x) promoted diffusion bonding at the interface,which contributed to the high mechanical properties of the W/Mo joint.With an increase in the Ni content of the Cu_(1-x)Ni_(x) coating interlayer,the Mo Ni intermetallic compound(IMC)nucleated and grew at the Cu1-xNix coating/Mo1 interface.When the Ni content of the Cu_(1-x)Ni_(x) coating interlayer was above 50%,the generation of a brittle Mo Ni IMC weakened the shear strength of the W/Mo joint dramatically.