Related papers: Hydrogen in $\alpha$-iron: stress and diffusion

Hydrogen-enhanced decohesion (HEDE) is one of the many mechanisms of hydrogen embrittlement, a phenomenon that severely impacts structural materials such as iron and iron alloys. Grain boundaries (GBs) play a critical role in this…

Density functional calculations are employed to study the molecular dissociation of hydrogen on graphene, the diffusion of chemisorbed atomic species, and the electronic properties of the resulting hydrogen on graphene system. Our results…

We examine the behaviour of hydrogen ions, atoms and molecules in alpha-boron using density functional calculations. Hydrogen behaves as a negative-U centre, with positive H ions preferring to sit off-center on inter-layer bonds and…

Graphene layers are stable, hard, and relatively inert. We study how tensile stress affects $\sigma$ and $\pi$ bonds and the resulting change in the chemical activity. Stress affects more strongly $\pi$ bonds that can become chemically…

We report first principles ab initio density functional calculations of hydrogen dynam- ics in hydrogenated amorphous silicon. Thermal motion of the host Si atoms drives H diffusion, as we demonstrate by direct simulation and explain with…

Time-dependent density-functional theory simulations are performed to examine the effects of varying incident points and kinetic energies of hydrogen atom projectiles on a graphene-like structure. The simulations reveal that the incident…

Ab initio density functional theory has been used to analyze flexural modes, elastic constants, and atomic corrugations on single and bi-layer graphene. Frequencies of flexural modes are sensitive to compressive stress; its variation under…

Hydrogen embrittlement mechanisms of steels have been studied for several decades. Understanding hydrogen diffusion behavior in steels is crucial towards both developing predictive models for hydrogen embrittlement and identifying…

The diffusion of tungsten in {\alpha}-iron is important for the application of ferritic-iron alloys to thermal power plants. These data, over a wide temperature range across the Curie temperature, have been recently reported. We show that…

The adsorption of atomic oxygen and its inclusion into subsurface sites on Ag(210) and Ag(410) surfaces have been investigated using density functional theory. We find that--in the absence of adatoms on the first metal layer--subsurface…

Refractory high-entropy alloys (RHEAs) have emerged as promising candidates for extreme high-temperature applications, for example, in next-generation turbines and nuclear reactors. In such applications, atomic diffusion critically governs…

Hydrogen uptake in complex multicomponent alloys, including high-entropy alloys (HEAs), governs both hydrogen storage capacity and resistance to hydrogen-induced degradation. We combine high-pressure experiments, density-functional theory…

External magnetic fields reduce diffusion of carbon in BCC iron, but the physical mechanism is not understood. Using DFT calculations with magnetic moments sampled from a Heisenberg model, we calculate diffusivities of carbon in iron at…

We present calculations of free energy barriers and diffusivities as functions of temperature for the diffusion of hydrogen in bcc-Fe. This is a fully quantum mechanical approach since the total energy landscape is computed using a new self…

The effect of hydrogen adsorption on the magnetic properties of an Fe$_3$ cluster immersed in a Cu(111) surface has been calculated using densifty functional theory and the results used to parametrize an Alexander-Anderson model which takes…

Hydrogen embrittlement remains a critical challenge in structural and electronic applications of copper (Cu) but its mechanism is still not fully understood. In this study, we combine density functional theory (DFT) and bond-order potential…

Sykes {\it et al.} [Proc. Natl. Acad. Sci. {\bf 102}, 17907 (2005)] have reported how electrons injected from a scanning tunneling microscope modify the diffusion rates of H buried beneath Pd(111). A key point in that experiment is the…

The reported diffusion constants for hydrogen in silicon vary over six orders of magnitude. This spread in measured values is caused by the different concentrations of defects in the silicon that has been studied. Hydrogen diffusion is…

The energy landscape and diffusion barriers of protonic defects in Gd-doped BaCeO3, a compound candidate as electrolyte for protonic ceramic fuel cells, have been investigated by density functional theory calculations, starting from a…

A known issue for future nuclear reactors is helium accumulation inside the steel structure materials, responsible for structural issues such as embrittlement and cracking. One possible solution is using new types of reinforced steel, such…