Simulation of bulk and grain boundary diffusion phenomena in a high entropy CoCrFeMnNi alloy by molecular dynamics

Abstract

A series of calculations on the self-diffusion behavior of high entropy CoCrFeMnNi alloy were carried out using molecular dynamics methods. By computing both vacancy formation energy and atomic migration energy of the constituent elements in the alloy, the diffusional activation energy of each element is obtained, and the self-diffusion coefficients for bulk diffusion were calculated, with the values exhibiting close to of experiments. A model for structures of symmetrically tilted grain boundary is established, with Σ9 and Σ27 grain boundaries studied based on the coincidence site lattice theory. Measured by the full width at half maxima of the radial distribution function, it is found that the grain boundaries with low index are more ordered than those with high plane index, and the atom fluctuation occurred in the low-indexed grain boundaries is less intensively and sensitively to temperature change. Meanwhile, the diffusion coefficients of ordered grain boundaries are generally smaller than those of disordered grain boundaries. Compared with the experimental values of grain boundary diffusion, the diffusion activation energy of configured grain boundaries from coincidence site lattice is smaller than that of normal large-angle grain boundaries.

Mechanical characteristics and electrochemical corrosion of NiCoCr alloys

“…In addition, mechanical properties and corrosion resistance are crucial to the application of MEAs/HEAs in biomedical, marine transportation, new energy technology, defence, and aerospace industries [2][3][4][5][6][7]. Many researchers have paid particular attention to increasing the corrosion resistance of materials and profoundly investigating the subjects that can directly or indirectly affect corrosion resistance [8][9][10][11]. Yan et al investigated the effect of Cr content on microstructure, corrosion behavior, and mechanical properties of Al 0.3 Cr x FeCoNi HEAs [12].…”

Investigation of the Dislocation Density of NiCr Coatings Prepared Using PVD–LMM Technology

“…Molecular dynamics simulations may be used to analyze the evolution of the dislocations resulting from LMM treatment. Indeed, many studies addressing the evolution of the crystals and defects of materials in complex environments have been carried out based on molecular dynamics simulations, and the simulation results have been verified via experiments [19][20][21][22][23][24][25][26][27][28].…”