Effect of Dwelling Time on Microstructure and Property of Cemented Carbide/Steel Joint Fabricated by Partial Transient Liquid Phase Bonding

The sandwich structural titanium foil/nickel foil/titanium foil were used as interlayer materials, and then the dissimilar metal joint of YG10 cemented carbide and 40Cr steel was prepared by partial transient liquid phase (PTLP) bonding at 1 000℃ for different dwelling times (1-4 h). The effects of dwelling time on the micromorphology, phase composition and shear strength of the joint were investigated. The results show that the joint had a multilayer structure composed of YG10 cemented carbide/TiC+WC/Co-Ni-Ti/Ni₃Ti/nikle layer/Ni₃Ti/NiTi/TiC/40 Cr steel, and a transition layer with width of 30-50 μm was formed between cemented carbide and nickle layer, and between steel and nickle layer, respectively. When the dwelling time increased from 1 h to 4 h, the amount of microcavities in the transition layer of the joint decreased, the thickness of the transition layer increased, and the shear strength of the joint increased first and then decreased. After dwelling for 2 h, the shear strength of the joint reached the largest value of 153 MPa.