Point defect concentrations of impurity carbon in tungsten

Our recent investigations (Y.-L. Liu, H.-B. Zhou, Y. Zhang, G.-H. Lu, G.-N. Luo, Comput. Mater. Sci. 50 (2011) 3213) show that impurity carbon (C) easily bonds onto vacancy internal-surface and a monovacancy is capable of trapping as many as 4 C atoms to form CnV complexes in W, but the concentration distributions of point defects such as CnV complexes are lacking. Based on first-principles calculations combined with statistical model, we predict point defect concentrations of impurity C in W and find that the concentration of vacancy in the form of CnV complexes notablely increase with the presence of C, although the concentration of interstitial C is still higher than that of CnV complexes in W. We believe that the present method can be also generally applicable for predicting the concentration distribution of other impurities in other metals and metal alloys.