Insight into interface cohesion and impurity-induced embrittlement in carbide dispersion strengthen tungsten from first principles

The fundamental understanding of interface properties is crucial in materials design and lifetime predictions. In this work, the stability, adhesion and impurity-induced embrittlement of interfaces between tungsten (W) and transition metal carbides (TMC = ZrC, TiC, TaC, HfC, MoC, and VC) have been investigated by first-principles calculations. For all the systems, the coherent W (100)-TMC(100) interfaces show better stability with lower interface energies than the semi-coherent W (110)-TMC(100) ones. The impurities hydrogen, helium, oxygen, and nitrogen tend to segregate to the coherent interfaces and act as strong embrittlers. Furthermore, the interface could provide a low-barrier channel to facilitate hydrogen and helium transport. The present work provides key mechanistic insights towards interpreting recent experimental studies of the interface structure and the hydrogen isotope retention in W-ZrC, W-TiC, and W-TaC materials under irradiation and guides the preparation of future W-based materials with good resistance to irradiation damage. (c) 2020 Elsevier B.V. All rights reserved.