Molecular dynamics-based analysis of the effect of voids and HCP-Phase inclusion on deformation of single-crystal CoCrFeMnNi high-entropy alloy

Qi, Yuming; Chen, Xiuhua; Feng, Miaolin

doi:10.1016/j.msea.2020.139444

Cited by 48 publications

(6 citation statements)

References 30 publications

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“…[28] Moreover, void growth in high entropy alloys has also been studied. [29,30] Mg is the primary alloying element of Al alloys. Although the mechanical behaviors of Al-Mg alloys have been extensively reported, a systematical study on the plastic deformation mechanism of pre-void Al-Mg alloys is still lacking.…”

Section: Introductionmentioning

confidence: 99%

Effect of void size and Mg contents on plastic deformation behaviors of Al–Mg alloy with pre-existing void: Molecular dynamics study

Wei

Shi

et al. 2022

Chinese Phys. B

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The plastic deformation properties of cylindrical pre-void Aluminum-Magnesium (Al-Mg) alloy under uniaxial tension are explored using molecular dynamics simulations with embedded atom method (EAM) potential. The factors of Mg content, void size, and temperature are considered. The results show that the void fraction decreases with increasing Mg in the plastic deformation, and it is almost independent of Mg content when Mg is beyond 5%. Both Mg contents and stacking faults around the void affect the void growth. These phenomena are explained by the dislocation density of the sample and stacking faults distribution around the void. The variation trends of yield stress caused by void size are in good agreement with Lubarda model. Moreover, temperature effects are explored, the yield stress and Young's modulus obviously decrease with temperature. Our results may enrich and facilitate the understanding of the plastic mechanism of Al-Mg with defects or other alloys.

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Section: Introductionmentioning

confidence: 99%

Effect of void size and Mg contents on plastic deformation behaviors of Al–Mg alloy with pre-existing void: Molecular dynamics study

Wei

Shi

et al. 2022

Chinese Phys. B

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“…Qi et al [10] studied tensile deformation in single-crystal CoCrFeMnNi HEA containing voids of different sizes but no initial dislocations. As typical for this kind of simulation, the stress-strain curves are dominated by a giant yield drop due to the high stress needed for dislocation nucleation, whereas the presence or absence of voids is nearly irrelevant for the deformation behavior.…”

Section: Resultsmentioning

confidence: 99%

“…However, the fundamental mechanisms of dislocation-obstacle interactions in CSAs are still not well understood. In particular, the effect of voids as obstacles for dislocation motion in CSAs has not been extensively studied [9,10].…”

Section: Introductionmentioning

confidence: 99%

Atomistic Simulations of Dislocation-Void Interactions in Concentrated Solid Solution Alloys

Vaid,

Zaiser,

Bitzek

2023

Metals

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This paper investigates the interaction of edge dislocations with voids in concentrated solid solution alloys (CSAs) using atomistic simulations. The simulation setup consists of edge dislocations with different periodicity lengths and a periodic array of voids as obstacles to dislocation motion. The critical resolved shear stress (CRSS) for dislocation motion is determined by static simulations bracketing the applied shear stress. The results show that shorter dislocation lengths and the presence of voids increase the CRSS for dislocation motion. The dislocation–void interaction is found to follow an Orowan-like mechanism, where partial dislocation arms mutually annihilate each other to overcome the void. Solute strengthening produces a ‘friction stress’ that adds to the Orowan stress. At variance with classical theories of solute pinning, this stress must be considered a function of the dislocation line length, in line with the idea that geometrical constraints synergetically enhance the pinning action of solutes. Modifying the equation by Bacon, Kocks and Scattergood for void strengthening to account for the solute hardening in CSAs allows one to quantitatively predict the CRSS in the presence of voids and its dependency on void spacing. The predictions show good agreement with the simulation data without invoking any fit parameters.

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“…MD simulations are performed with LAMMPS, and the well-validated MEAM potential is used. This potential has been widely adopted in describing the physical and mechanical properties of the FCC-phased CoCrFeMnNi alloy system , and is also used in FCC/HCP DP CoCrFeMnNi alloy systems. ,, In addition, to further verify the reliability of the potential function, we calculate the lattice constant, cohesive energy, elastic properties, and stacking fault energy of the HCP-phased CoCrFeMnNi HEA by means of MD simulations and compare the results with those of first-principles calculations (see Supporting Information for more details). The atomistic models are first optimized by the conjugate gradient algorithm and then annealed at 600 K for reaching the thermodynamic steady state.…”

Section: Atomistic Simulation Approachmentioning

confidence: 99%

Phase Volume Fraction-Dependent Strengthening in a Nano-Laminated Dual-Phase High-Entropy Alloy

2022

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A recently synthesized FCC/HCP nano-laminated dual-phase (NLDP) CoCrFeMnNi high entropy alloy (HEA) exhibits excellent strength–ductility synergy. However, the underlying strengthening mechanisms of such a novel material is far from being understood. In this work, large-scale atomistic simulations of in-plane tension of the NLDP HEA are carried out in order to explore the HCP phase volume fraction-dependent strengthening. It is found that the dual-phase (DP) structure can significantly enhance the strength of the material, and the strength shows apparent phase volume fraction dependence. The yield stress increases monotonously with the increase of phase volume fraction, resulting from the increased inhibition effect of interphase boundary (IPB) on the nucleation of partial dislocations in the FCC lamella. There exists a critical phase volume fraction, where the flow stress is the largest. The mechanisms for the volume fraction-dependent flow stress include volume fraction-dependent phase strengthening effect, volume fraction-dependent IPB strengthening effect, and volume fraction-dependent IPB softening effect, that is, IPB migration and dislocation nucleation from the dislocation–IPB reaction sites. This work can provide a fundamental understanding for the physical mechanisms of strengthening effects in face-centered cubic HEAs with a nanoscale NLDP structure.

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Molecular dynamics-based analysis of the effect of voids and HCP-Phase inclusion on deformation of single-crystal CoCrFeMnNi high-entropy alloy

Cited by 48 publications

References 30 publications

Effect of void size and Mg contents on plastic deformation behaviors of Al–Mg alloy with pre-existing void: Molecular dynamics study

Effect of void size and Mg contents on plastic deformation behaviors of Al–Mg alloy with pre-existing void: Molecular dynamics study

Atomistic Simulations of Dislocation-Void Interactions in Concentrated Solid Solution Alloys

Phase Volume Fraction-Dependent Strengthening in a Nano-Laminated Dual-Phase High-Entropy Alloy

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