Effect of short-range ordering and grain boundary segregation on shear deformation of CoCrFeNi high-entropy alloys with Al addition

Babicheva, Rita I.; Jarlöv, Asker; Han, Zheng; Дмитриев, С. В.; Korznikova, Elena A.; Nai, Mui Ling Sharon; Ramamurty, Upadrasta; Zhou, Kun

doi:10.1016/j.commatsci.2022.111762

Cited by 29 publications

(8 citation statements)

References 64 publications

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“…To form Al-3at.%Zr alloy with Zr atoms located at GBs of Al, 3 at.% of all Al atoms (~6300 atoms for the big sample and ~790 atoms for the small one) are randomly replaced by Zr atoms within strips of 4 Å thickness at each GB [28][29][30][31]. In Figure 2, the Al (Zr) atoms are shown by red (blue) dots.…”

Section: Simulation Detailsmentioning

confidence: 99%

A Molecular Dynamics Simulation to Shed Light on the Mechanical Alloying of an Al-Zr Alloy Induced by Severe Plastic Deformation

Morkina,

Babicheva,

Korznikova

et al. 2023

Metals

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In a recent experimental work, as a result of severe plastic deformation, a non-equilibrium solid solution was obtained despite the very limited solubility of zirconium (Zr) in aluminum (Al). This opens up a new path in the development of heat-treatable alloys with improved electrical and mechanical properties, where mechanically dissolved elements can form intermetallic particles that contribute to precipitation strengthening. In the present study, molecular dynamics simulations were performed to better understand the process of mechanical dissolution of Zr within an Al model, with Zr atoms segregated along its grain boundaries. Stress–strain curves, radial distribution functions, and mechanisms of plastic deformation and dissolution of Zr in Al were analyzed. It is revealed that orientation of the grain boundary with segregation normal to the shear direction promotes more efficient mixing of alloy components compared to its parallel arrangement. This happens because in the second case, grain boundary sliding is the main deformation mechanism, and Zr tends to remain within the interfaces. In contrast, the involvement of dislocations in the case of normal orientation of grain boundaries with Zr segregation significantly contributes to deformation and facilitates better dissolution of Zr in the Al matrix. The findings obtained can provide new insights considering the role of texture during mechanical alloying of strongly dissimilar metals.

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Section: Simulation Detailsmentioning

confidence: 99%

A Molecular Dynamics Simulation to Shed Light on the Mechanical Alloying of an Al-Zr Alloy Induced by Severe Plastic Deformation

Morkina,

Babicheva,

Korznikova

et al. 2023

Metals

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“…We performed the molecular dynamics (MD) calculations of generalized stacking fault energy (GSFE) using the large-scale atomic/molecular massively parallel simulator (LAMMPS) package [ 22 ] with an embedded-atom method (EAM) interatomic potential [ 23 , 24 , 25 , 26 ]. The calculation of GSFE was performed with a 5.0 × 12.3 × 8.7 nm 3 simulation cell oriented with

, [111] and

directions, containing 48,000 atoms.…”

Section: Methodsmentioning

confidence: 99%

Plasticity Improvement in a Co-Rich Co40Fe25Cr20Ni15 High-Entropy Alloy via Al Alloying

Chen

Nutor

et al. 2023

Materials

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The mechanical properties of high-entropy alloys (HEAs) can be regulated by altering the stacking fault energy (SFE) through compositional modulation. The Co-rich HEAs, exhibiting deformation twinning and even strain-induced martensitic transformation at room temperature, suffer from insufficient ductility at high strength. In this work, we developed Co-rich (Co40Fe25Cr20Ni15)100−xAlx (x = 0 and 5 at.%) HEAs and investigated their tensile behaviors at room temperature. The addition of Al resulted in a massive improvement in the strength-ductility product, even at similar grain sizes, and also altered the fracture mode from quasi-cleavage to ductile dimple fracture. Interestingly, both alloys were deformed by mechanical twinning, which was also verified by molecular dynamics (MD) simulations. The MD simulations revealed the SFE increased upon Al addition; however, the slip energy barrier was reduced, which favored the mobility of dislocations and twinning propensity to prolong strain hardening. The present findings provide further insights into the regulation of mechanical properties of HEAs by Al-alloying.

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“…Besides, ϕ ij is the interaction potential between atoms i and j. These potentials are particularly effective in reproducing the stacking fault energies, enabling investigations of both mechanical and thermodynamic behaviors that involve stacking faults, for example, dislocation motion [33], crystallographic order and atomic segregation under heating [34] or deformation [35], and growth pattern of nucleation during solidification [36]. Specifically, for Cr-Co binary random alloy, the lattice parameter, heat of mixing, cohesive energy, and deviation from Vegard's law are fitted to be 3.539 nm, 0.144 kJ mol −1 , −4.303 eV atom −1 , and −0.03% [31].…”

Section: Computational Methodologymentioning

confidence: 99%

Crystallization kinetics, microstructure evolution, and mechanical responses of Cr-Co alloys

Wu,

Huang,

Wen

2023

Modelling Simul. Mater. Sci. Eng.

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Understanding the crystallization kinetics of Cr-Co alloys and providing a quantitative characterization of the microstructure evolution during quenching are of practical significance to their industrial applications. Using molecular dynamics simulations, we investigate the solidification of Cr30Co70 and Cr70Co30 subjected to different cooling rates. Besides, the outcomes are examined for their mechanical responses under uniaxial tensile loading. It is disclosed that slower cooling (≤ 1 K/ps) is beneficial to crystallization, while faster quenching generally leads to disordered structures. In the solidified outcomes, regardless of composition ratios and cooling rates, Co-Co bonding is the most favorable compared with that of Co-Cr and Cr-Cr. As for structural order, the Co-rich alloys exhibit a hexagonal close-packed (hcp) dominant crystalline order, while face-centered cubic (fcc) becomes more advantageous in the remaining cases. Among all the samples, the Cr30Co70 obtained with 0.5 K/ps is an exception since it abnormally adopts fcc as a major crystalline order and realizes lower energy than expected. Additionally, under uniaxial tensile loading, a phase transition from fcc or hcp to body-centered cubic (bcc) is identified in the Cr30Co70 samples, while it is absent in the Cr70Co30 ones. These findings can aid in the design, manufacturing, and utilization of Cr-Co alloys in the field of material industry.

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Effect of short-range ordering and grain boundary segregation on shear deformation of CoCrFeNi high-entropy alloys with Al addition

Cited by 29 publications

References 64 publications

A Molecular Dynamics Simulation to Shed Light on the Mechanical Alloying of an Al-Zr Alloy Induced by Severe Plastic Deformation

A Molecular Dynamics Simulation to Shed Light on the Mechanical Alloying of an Al-Zr Alloy Induced by Severe Plastic Deformation

Plasticity Improvement in a Co-Rich Co40Fe25Cr20Ni15 High-Entropy Alloy via Al Alloying

Crystallization kinetics, microstructure evolution, and mechanical responses of Cr-Co alloys

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