Diffusion of hydrogen within idealized grains of bcc Fe: A kinetic Monte Carlo study

2012/06/11 by Yaojun A. Du, Jutta Rogal, Ralf Drautz · 77 citations
Chemistry · Materials Science · Physics and Astronomy · #Chemical physics #Chemistry #Diffusion #Effective diffusion coefficient #Embrittlement #Fusion materials and technologies #Grain boundary #Grain boundary diffusion coefficient #Hydrogen #Hydrogen embrittlement #Hydrogen embrittlement and corrosion behaviors in metals #Kinetic Monte Carlo #Materials science #Metallurgy #Microstructure #Monte Carlo method #Nuclear Materials and Properties #Physics #Thermal diffusivity #Thermodynamics #cond-mat.mtrl-sci

paper · pdf · doi:10.1103/physrevb.86.174110

published in Physical Review B 86(17) (American Physical Society)

arxiv created 2012/06/11 · openalex publication_date 2012/11/14 · openalex created_date 2016/06/24 · arxiv updated 2019/06/18 · openalex updated_date 2026/08/05

Abstract

Structural defects in materials such as vacancies, grain boundaries, and dislocations may trap hydrogen and a local accumulation of hydrogen at these defects can lead to the degradation of the materials properties. An important aspect in obtaining insight into hydrogen-induced embrittlement on the atomistic level is to understand the diffusion of hydrogen in these materials. In our study we employ kinetic Monte Carlo (kMC) simulations to investigate hydrogen diffusion in bcc iron within different microstructures. All input data to the kMC model, such as available sites, solution energies, and diffusion barriers, are obtained from first-principles calculations. We find that hydrogen mainly diffuses within the interface region with an overall diffusivity that is lower than in pure bcc Fe bulk. The concentration dependence of the diffusion coefficient is strongly nonlinear and the diffusion coefficient may even decrease with an increasing hydrogen concentration. To describe the macroscopic diffusion coefficient we derive an analytic expression as a function of hydrogen concentrations and temperatures which is in excellent agreement with our numerical results for idealized microstructures.

Citations

• Frequency factors and isotope effects in solid state rate processes
• The diffusion and trapping of hydrogen in steel
• Equilibrium aspects of hydrogen-induced cracking of steels
• A general method for numerically simulating the stochastic time evolution of coupled chemical reactions
• A new model for hydrogen-assisted cracking (hydrogen “embrittlement”)
• Hydrogen solubility and diffusivity in defective and amorphous metals
• Ab initiomolecular dynamics for liquid metals
• Efficient iterative schemes forab initiototal-energy calculations using a plane-wave basis set
• Self-Consistent Equations Including Exchange and Correlation Effects
• Atoms, molecules, solids, and surfaces: Applications of the generalized gradient approximation for exchange and correlation