Atomistic modeling of dislocation cross-slip in nickel using free-end nudged elastic band method

Chen, Dengke; Costello, Luke; Geller, Clint B.; Zhu, Ting; McDowell, David L.

doi:10.1016/j.actamat.2019.02.035

Cited by 42 publications

(14 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…More recently, an atomistically based model has been proposed to compute the energy barrier for cross-slip as a function of the type and volume fraction of solute atoms [25,26]. Additionally, Chen et al [27] studied the effect of vacancy clusters on the cross-slip activation energy in pure Ni, employing the free-end nudged elastic band methodology. They reported an overcoming mechanism map (cross-slip vs. shearing) as a function of the stress and obstacle spacing.…”

Section: Introductionmentioning

confidence: 99%

Influence of the stress state on the cross-slip free energy barrier in Al: An atomistic investigation

et al. 2020

View full text Add to dashboard Cite

The influence of the stress state on the cross-slip rate in Al was analyzed by means of molecular dynamics simulations and transition state theory. The activation energy barrier in the absence of thermal energy was determined through the nudged elastic band method while the cross-slip rates were determined using molecular dynamics simulations for different magnitudes of the Schmid stress on the cross-slip plane, and of the Escaig stresses on the cross-slip and glide planes. The enthalpy barrier and the effective attempt frequency were determined from the average rates of cross-slip obtained from the molecular dynamics simulations. It was found that the different stress states influence the cross-slip rate assuming harmonic transition state theory. Moreover, the theoretical contributions to the enthalpy barrier (configurational and due to the interaction of the applied stress with the local stress field created by the defect) were identified from the atomistic simulations while the entropic contribution to the activation energy could be estimated by the Meyer-Neldel rule. Based on these results, an analytical expression of the activation enthalpy for cross-slip in Al as a function of the different combinations of Schmid and Escaig stress states was developed and validated. This expression can be easily used in dislocation dynamics simulations to evaluate the probability of cross-slip of screw dislocation segments.

show abstract

Section: Introductionmentioning

confidence: 99%

Influence of the stress state on the cross-slip free energy barrier in Al: An atomistic investigation

et al. 2020

View full text Add to dashboard Cite

show abstract

“…3a, thus constituting various possible transition pathways. Among them, MEP is a representative transition pathway on the EL that researchers are mostly concerned [28,33,37], for it tells the most probable evolution direction. In this section, the MEP of 2Ti-vacancy complex is compared with other kinds of titanium-vacancy complexes: Ti-vacancy and 4Ti-vacancy complex.…”

Section: Resultsmentioning

confidence: 99%

“…The CINEB method is adopted to determine the transition states and calculate the transition barriers during the titanium-vacancy complex evolution. This approach allows quantitative prediction of the MEP while providing physical fidelity for the atomic trajectories [33]. The ABC method is implemented to search the energy landscape and uncover possible atomic configurations of a complex.…”

Section: Models and Methodsmentioning

confidence: 99%

The structure evolution of titanium–vacancy complex in a vanadium-based alloy

Tang

Guo

2020

J Mater Sci

View full text Add to dashboard Cite

Under irradiation conditions, excess point defects interact strongly with the solute atoms in fusion reactor materials. The solutes can bind with point defects and form clusters such as solute-vacancy complexes. The evolution of these complexes at long timescale significantly influences the mechanical properties of the irradiated materials. In this study, we mainly use climbing image nudged elastic band method to investigate the evolution and migration of titaniumvacancy complexes in a vanadium-based alloy. The transition pathways associated with atomic trajectories of complex evolution in bulk and in grain boundary vicinity are calculated. Results show that both basin energies and transition barriers are affected when a complex is in grain boundary vicinity. The evolution is revealed to be driven by multiple titanium-vacancy interactions synergistically. The migration is supposed to be induced by two mechanisms: the vacancy reorientation jumps and complex dissociation-reformation which are both based on titanium-vacancy interactions. This research contributes to the understanding of solute diffusion and early-stage radiation defects in vanadium-based alloys.

show abstract

“…Some NEB algorithms do not require fixed endpoints. [23][24][25] Figure 1 shows a mass and spring representation of NEB. Each replica is an atomic representation of the system at a certain position along the pathway that connects the initial and final states.…”

Section: Theorymentioning

confidence: 99%

A Fast Implementation of the Nudged Elastic Band Method in AMBER

Ghoreishi¹,

Cerutti²,

Fallon³

et al. 2019

Preprint

View full text Add to dashboard Cite

We present a fast implementation of the nudged elastic band (NEB) method into the particle mesh Ewald molecular dynamics (pmemd) module of the Amber software package both for central processing units (CPU) and graphics processing units (GPU). The accuracy of the new implementation has been validated for three cases: a conformational change of alanine dipeptide, the α-helix to ß-sheet transition in polyalanine, and a large conformational transition in human 8-oxoguanine–DNA glycosylase with DNA complex (OGG1–DNA). Timing benchmark tests were performed on the explicitly solvated OGG1–DNA system containing ~50k atoms. The GPU-optimized implementation of NEB achieves more than two orders of magnitude speedup compared to the previous CPU implementation performed with a two-core CPU processor. The speed and scalable features of this implementation will enable NEB applications on larger and more complex systems.

show abstract

Atomistic modeling of dislocation cross-slip in nickel using free-end nudged elastic band method

Cited by 42 publications

References 42 publications

Influence of the stress state on the cross-slip free energy barrier in Al: An atomistic investigation

Influence of the stress state on the cross-slip free energy barrier in Al: An atomistic investigation

The structure evolution of titanium–vacancy complex in a vanadium-based alloy

A Fast Implementation of the Nudged Elastic Band Method in AMBER

Contact Info

Product

Resources

About