Interfacial structure of WC-Fe metal-matrix composite (WC/Fe3W3C and Fe/Fe3W3C) stability, electronic and mechanical properties from first-principles calculations

The adhesion work, interfacial energy, electronic structure and interfacial bonding mechanism of WC/Fe3W3C and Fe/Fe3W3C were calculated based on first-principles density functional theory (DFT). The results show that WC(100)-w/Fe3W3C(110) interface has lower interfacial energy (0.9584 J/m2) and higher adhesion work (0.3265 J/m2) than WC(111)-w/Fe3W3C(110), Fe(110)/Fe3W3C(110) has lower interfacial energy (−4.0388 J/m2) and higher adhesion work (10.7346 J/m2) than Fe(211)/Fe3W3C(110). It is obvious that Fe(110)/Fe3W3C(110)has the most stable interface structure and the strongest bond strength. The differential charge density and partial wave density of states (PDOS) show that the average number of C-W bonds at the interface is the most 0.37, and the covalent bond is strong. Fe-Fe and Fe-W bonds are formed at the interface to form interface bonds. The Fe-d orbital show extremely strong metallicity near the Fermi energy level, and Fe-Fe and Fe-W are easier to form metallic and ionic bonds. The above results provide important guidance for improving the interfacial strength and stability of WC-Fe metal-matrix composite.