Effects of the interface and mechanical properties of GNPs/TA15 composites through adding B powders

Abstract

The severe interfacial reaction between graphene nanoplatelets (GNPs) and Ti matrix weakened the bonding strength. The severe interfacial reaction was resolved successfully though adding B powders. The B powders distributed on the surface of TA15 powders by low energy ball milling, and then the GNPs coated the mixture powders in the same way. During the process of pre-sintering and canned hot extrusion, a part of B atoms primarily diffused to the vacant sites to form BC bonds for making up the nanostructure of GNPs, leading to the higher diffusion activation energy of C atoms. The interfacial reaction was inhibited preliminarily. Moreover, Bits of B atoms were adsorbed on the bridge of CC bond sites, resulting in solubilizing in the (002) plane of GNPs. And the rest of B atoms diffused to the Ti matrix by the way of solution. The diffusion of the C atoms near B atoms was hindered, due to the higher diffusion rate of C atoms, resulting that the interfacial reaction was inhibited further. As a result, the interface with nano-TiC and nano-TiB was obtained. What's more, 0.4% wt% GNPs/TA15 composites with 0.05% wt% B powders exhibited satisfactory mechanical properties with an ultimate tensile strength of 1349 MPa and a fracture elongation of 8.9%. This work provided a new strategy for resolving the severe interfacial reaction to obtain the expectant interface and performance of TMCs.