First-principles calculations on FeWB bulk and FeWB(001)/α-Fe(111) interface

FeWB bulk and FeWB(001)/alpha-Fe(111) interface were studied by first-principles calculations. FeWB bulk bonding has the mixed characteristics of metallicity, covalency and ionicity, among which the metallicity is the most obvious. Such combination endows FeWB with promising toughness and excellent electrical conductivity. Adhesion work, W-ad, was calculated for twelve different interfacial structures, taking into account four terminations of FeWB(001) and three stacking sequences. The B(Fe)-terminated center-site stacking interface is the most stable with the smallest interface distance and the largest W (ad) . Fe-B and W-B bond lengths at the interface are even shorter than those in FeWB bulk. By comparing the interface fracture work G with W-ad, it is found that the interface fracture position has a certain occasionality, but it tends to occur in FeWB bulk. According to the results of density of states, we concluded the B(Fe)-terminated center-site stacking interface is a metallic/covalent mixing nature, while the combination of top-site stacking interface is mainly covalent bonds.