The effect mechanism of Zn, Ni and Mn solute elements on the WC/Cu-based filler metal interfacial properties: first-principles calculations and experiments

In this work, the first-principles calculation was performed to investigate the effect mechanism of Zn, Ni and Mn solute elements on the WC/Cu-based filler metal interfacial properties, and the CuZnNiMn filler metal was designed, the diffusion behavior of interface elements was verified by experiments. Firstly, Zn, Ni and Mn element doping WC/Cu interface models were established respectively. The effect natures of alloying elements on the interfacial properties were explored by adhesive strength and interfacial electronic structure. The results show that Zn element slightly aggregate into the Cu matrix interior after full relaxation, which has little effect on the interface structure, but it can lower the melting point and optimize the properties of Cu-based filler metals. Ni, Mn elements tend to segregate toward the interface and form strong covalent bonds and metallic bonds with W atoms, which can significantly improve the interfacial bonding strength of WC/Cu. The Energy Dispersive Spectroscopy (EDS) analysis of the WC/CuZnNiMn interface region proves that the diffusion effect of Zn in the interface is not obvious, while the Ni and Mn elements strongly diffuse into the WC particle, which has a positive effect on the metallurgical bonding of the brazed joint.(c) 2022 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).