Ab-initio molecular modeling of interfaces in tantalum-carbon system

Processing of ultrahigh temperature TaC ceramic material with sintering additives of B 4C and reinforcement of carbon nanotubes (CNTs) gives rise to possible formation of several interfaces (Ta 2C-TaC, TaC-CNT, Ta 2C-CNT, TaB 2-TaC, and TaB 2-CNT) that could influence the resultant properties. Current work focuses on interfaces developed during spark plasma sintering of TaC-system and performing ab initio molecular modeling of the interfaces generated during processing of TaC-B 4C and TaC-CNT composites. The energy of the various interfaces has been evaluated and compared with TaC-Ta 2C interface. The iso-surface electronic contours are extracted from the calculations eliciting the enhanced stability of TaC-CNT interface by 72.2. CNTs form stable interfaces with Ta 2C and TaB 2 phases with a reduction in the energy by 35.8 and 40.4, respectively. The computed Ta-C-B interfaces are also compared with experimentally observed interfaces in high resolution TEM images. © 2012 American Institute of Physics.