Effects of cryogenic temperature on tensile and impact properties in a medium-entropy VCoNi alloy

Yang, Dae Cheol; Jo, Yong Hee; Ikeda, Yûji; Körmann, Fritz; Sohn, Seok Su

doi:10.1016/j.jmst.2021.02.034

Cited by 55 publications

(9 citation statements)

References 59 publications

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“…The depinning stress for equimolar VCoNi at 300 K is 410 ± 20 MPa, which is in good agreement with the experimental value of friction stress (383 MPa) for VCoNi at room temperature. The results show increasing the depinning stress by decreasing temperature from 300 to 5 K. This trend is in agreement with the experimental result for VCoNi Yang et al (2021); Hu et al (2021). Atomic mismatch (δ) for different compositions Varvenne et al (2016) shows a movie of a dislocation avalanche across pinning centers, combining snapshots such as the ones shown in Figures 2C,D, where dislocation transfers from one local pinning to the others.…”

Section: Resultssupporting

confidence: 89%

“…As it is obvious from this figure, V-clusters (with the highest atomic pressure) play an important role in dislocation pinning. In contrast to CrCoNi, deformation twinning has not been observed in deforming VCoNi at cryogenic temperatures Yang et al (2021). As reported in Ref.…”

Section: Resultsmentioning

confidence: 51%

“…Recent experiments showed a high strength of VCoNi medium entropy alloys at low and room temperature Yang et al (2021); Hu et al (2021). For example, in Ref.…”

Section: Introductionmentioning

confidence: 99%

“…In association, Ref. Yang et al (2021) concludes that at cryogenic temperatures, twinning is absent in VCoNi under tension or impact, while pinning of dislocations is primarily observed. Furthermore, the strength of equimolar VCoNi may be predicted by the Labusch-Varvenne class of solid solution analytical models Labusch (1970); Varvenne et al (2016); Yin et al (2020), which use the large atomistic mismatch of vanadium, to show that strength shall increase with respect to equiatomic CrCoNi.…”

Section: Introductionmentioning

confidence: 99%

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Atomistic simulations of dislocation plasticity in concentrated VCoNi medium entropy alloys: Effects of lattice distortion and short range order

Esfandiarpour

Alvarez-Donado²,

Papanikolaou³

et al. 2022

Front. Mater.

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Face-centered cubic (fcc) high and medium entropy alloys (H/MEAs) have been shown to display superior mechanical properties at low temperatures, but significant improvement of their strength at high temperatures is required for industrial applications at extreme conditions. Recently, it has been shown that the breakthrough of the MEAs from equiatomic/near-equiatomic to non-equiatomic ratios leads to strong MEAs with good ductility. To design new H/MEAs, we consider two important factors that may influence strength: the chemical composition and chemical short range order (CSRO). In this study, we investigate the depinning stress (σc) as a criterion of strength of several compositions of VCoNi concentrated solid solution alloys (CSSAs) including V0.33Co0.33Ni0.33, V0.35Co0.2Ni0.45, V0.33Co0.17Ni0.5, and V0.17Co0.33Ni0.5 at 5 K and 300 K, using atomistic simulations. The chosen interatomic potential is shown to be reliable by comparing experimental/ab initio values and calculated parameters such as lattice constant, shear modulus, depinning stress, and temperature variation of stacking fault width for equimolar VCoNi. We find a good agreement between experimental friction stress and the depinning stress extracted from our results for equimolar VCoNi. Also, we find that Vclusters are the main pinning points of dislocations, and With a random distribution of atoms, we find that the alloy composition V0.33Co0.17Ni0.5 displays the largest depinning stress at both 5 and 300 K. Furthermore, to investigate how CSRO affects the strength of these alloys, we design CSRO into the microstructure using two different methods: In the first method, hybrid Molecular-dynamics/Monte-Carlo simulations were employed to simulate annealing at various temperatures. We observe that such simulations create CSRO so that it increases with decreasing annealing temperature. Recently, the CSRO motif and its concentration in an equimolar VCoNi have been determined by experiment. By modeling this experiment, we also implemented the CSRO into microstructure as the second method. By using both methods, the effect of CSRO on the magnitude of the depinning stress is discussed. It was shown that in both methods, CSRO significantly influences the strength of non-equimolar VCoNi alloys.

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Section: Resultssupporting

confidence: 89%

Section: Resultsmentioning

confidence: 51%

“…Recent experiments showed a high strength of VCoNi medium entropy alloys at low and room temperature Yang et al (2021); Hu et al (2021). For example, in Ref.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Atomistic simulations of dislocation plasticity in concentrated VCoNi medium entropy alloys: Effects of lattice distortion and short range order

Esfandiarpour

Alvarez-Donado²,

Papanikolaou³

et al. 2022

Front. Mater.

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show abstract

“…This high yield strength mainly results from the high solid-solution strengthening and grain boundary strengthening. In addition, the alloy exhibits adequate ductility and strain hardening owing to the formation of nanosized dislocation substructure without secondary strengthening mechanisms, such as twinning and martensitic transformation even at cryogenic temperature [9] .…”

Section: Introductionmentioning

confidence: 99%

Effect of solid-solution strengthening on deformation mechanisms and strain hardening in medium-entropy V1-Cr CoNi alloys

Chung

Kim

Cho

et al. 2022

Journal of Materials Science & Technology

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Excellent combination of cryogenic strength and ductility of a metastable Fe65Ni15Co8Mn8Ti3Si medium entropy alloy through the exceptional deformation-induced martensitic transformation

et al. 2022

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Effects of cryogenic temperature on tensile and impact properties in a medium-entropy VCoNi alloy

Cited by 55 publications

References 59 publications

Atomistic simulations of dislocation plasticity in concentrated VCoNi medium entropy alloys: Effects of lattice distortion and short range order

Atomistic simulations of dislocation plasticity in concentrated VCoNi medium entropy alloys: Effects of lattice distortion and short range order

Effect of solid-solution strengthening on deformation mechanisms and strain hardening in medium-entropy V1-Cr CoNi alloys

Excellent combination of cryogenic strength and ductility of a metastable Fe65Ni15Co8Mn8Ti3Si medium entropy alloy through the exceptional deformation-induced martensitic transformation

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