Revealing the crystalline-amorphous W/B4C interface characteristic by first principles investigation

Abstract

In this study, three amorphous B4C structures (α-B12CCC, α-B11Ce-CBC, α-B11Cp-CBC) were modeled with W(110), W(200) and W(211) layers to establish W/α-B4C interfaces. The interface characteristics, such as the adhesion work, electronic structure, and tensile mechanical properties, was calculated using the first-principles method. In order to precisely investigate the role of C atoms in interfacial bonding, the properties of the interfaces formed between W and α-B11Cp-CBC with B-top and C-top (labeled as α-Btop-B11Cp-CBC and α-Ctop-B11Cp-CBC) was also studied respectively. It reports that W/α-B11Cp-CBC interfaces obtain the highest adhesion work, where W(200)/α-B11Cp-CBC interface has the most robust atomic bonding ability. The chemical bonding at the interface consists of ionic bonds, which makes it easier to form a stable interfacial structure. However, the reconstruction of W atoms in the W(200)/α-B11Cp-CBC interface occurred as the strain increased, while W(110)/α-B11Cp-B4C maintained excellent structural stability and toughness. W(110)/α-Btop-B11Cp-CBC and W(110)/α-Ctop-B11Cp-CBC interfaces performed excellent tensile strength of 26.7 GPa and 27.4 GPa, respectively, corresponding strains were 24 % and 16 %. The W-C bonding in the W(110)/α-Ctop-B11Cp-CBC interface significantly reduces its plasticity. Therefore, W(110)/α-Btop-B11Cp-CBC interface combines outstanding toughness and plasticity with maximum tensile strength. The tensile strength of the interface cannot be explained only by the work of adhesion.