Investigation on the WC/Cu interfacial bonding properties: First-principles prediction and experimental verification

In this research work, the first-principles calculation was used to predict the WC/Cu interfacial properties, and the prediction results were verified by experiments. The surface properties of different low-index surface models of WC(0001), WC(101¯0), WC(112¯0) and Cu (111), Cu (100), Cu (110) were firstly clarified. And then the nine low-index WC/Cu interface models with different configurations were constructed. The adhesive work, interfacial energy and electronic structure of WC/Cu interface were studied to predict the interfacial bonding properties. The results showed that W-terminated WC(0001)/Cu(111) interface with the stacking site of FCC has the highest adhesive work (4.270J/m2) and lowest interfacial energy (0.481-0.815J/m2) due to the strong metallic bonds and covalent bonds interactions between W and Cu atoms at the interface, which indicated that the W-terminated WC(0001)/Cu(111) interface is more likely to exist in reality. The high-resolution transmission electron microscope (HRTEM) experimental results have showed that the WC/Cu interface has the crystallographic orientation relationship of WC[112¯0]//Cu[1¯01], WC(0001)//Cu(111). The WC(0001)/Cu(111) interface displays a plane-to-plane matching with semi-coherent atomic correspondence, which are well consistent with the first-principles prediction results.