Wetting and brazing of Ni-coated WC-8Co cemented carbide using the Cu-19Ni-5AI alloy as the filler metal: Microstructural evolution and joint mechanical properties

摘要

The wetting of Cu-19Ni-5Al alloy on Ni-coated WC-8Co substrates with different coating thicknesses was investigated, and the brazing of Ni-coated WC-8Co to SAE1045 steel was performed by using the Cu-19Ni-5Al alloy as the filler metal. All the Cu-19Ni-5Al/Ni-coated WC-8Co systems present excellent wettability with a final contact angle of similar to 10 degrees. The thicknesses of the beta + gamma phase enriched with Co, Ni, and Al at the two joint interfaces increase and decrease with the Ni coating thickness, brazing temperature, and holding time increasing, respectively. The joint shear strength increases first and then decreases with the increase of Ni coating thickness, brazing temperature, or holding time. The maximum joint shear strength of similar to 328 MPa is obtained while Ni plating for 90 min and brazing at 1210 degrees C x 5 min.