Effect of Interstitial Hydrogen on the Mechanical and Thermal Properties of Tungsten: A First-Principles Study

• Published in: Journal of physical chemistry. C 2019-01, Vol.123 (3), p.1913-1921
• Main Authors: Luo, Min, Jiang, Diyou, Liu, Sanqiu, Ouyang, Chuying
• Format: Article
• Language: English
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/acs.jpcc.8b10659

Tungsten (W) was considered as one important candidate for the magnetically constrained plasma first wall materials. The H impurities have a strong influence on the mechanical and thermal properties of the W metal and seriously affect its service life. From first-principles calculations, we studied the influence of interstitial H on the mechanical and thermodynamic parameters such as elastic constant, elastic modulus, free energy, entropy, expansion coefficient, and phonon thermal conductivity of W. In particular, the temperature- and H concentration-dependent parameters are calculated, and the effect of H concentration on material’s performance is summarized. The results show that the mechanical strength of W metal decreases with the increase of H concentration. On the other hand, H impurity improves the ductility of the W metal, in agreement with previous reports in the literature. The thermal expansion coefficients of W increase with H impurity concentration. The phonon thermal conductivity of W is also strongly affected by H impurities, and it decreases with the increase of H concentration. These results suggest that H impurity is one important reason for the material degradation of W as a first wall material.