Author:
Tang Chunguang,Sun Gang,Liu Yun
Abstract
AbstractThe net effect of host phonons on interstitial diffusion has remained as a fundamental knowledge gap in our current theories since the motions of the host atoms and interstitials were coupled in these theories. Here we study this effect through molecular dynamics simulations of hydrogen diffusion in palladium, in which the motions can be decoupled through pinning the host atoms. Mathematically this decoupling corresponds to expanding the total diffusion coefficient into a Taylor series, which separates the phonon contribution from the intrinsic interstitial jumping. Our results clearly show that palladium phonons significantly promote hydrogen diffusion. The phonon contribution, being linear with temperature at high temperatures and exponential at low temperatures, is fitted with Brownian motion model. The total diffusion of interstitials can be understood as the intrinsic interstitial jumping in a pinned host plus phonon-induced Brownian diffusion. The generality of our findings is validated by examining the motion of lithium in manganese oxide and carbon in iron.
Publisher
Springer Science and Business Media LLC
Reference37 articles.
1. Porter, D. A., Easterling, K. E. & Sherif, M. Y. Phase Transformations in Metals and Alloys 3rd edn. (CRC Press, Taylor & Francis Group, New York, 2009).
2. Wert, C. Diffusion coefficient of C in a-Iron. Phys. Rev. 79, 601 (1950).
3. Wert, C. & Zener, C. Interstitial atomic diffusion coefficients. Phys. Rev. 76, 1169 (1949).
4. Vineyard, G. Frequency factors and isotope effects in solid state rate processes. J. Phys. Chem. Solids 3, 121 (1957).
5. Rice, S. dynamical theory of diffusion in crystals. Phys. Rev. 112, 804 (1958).
Cited by
2 articles.
订阅此论文施引文献
订阅此论文施引文献，注册后可以免费订阅5篇论文的施引文献，订阅后可以查看论文全部施引文献