The effect of Co and Cr substitutions for Ni on mechanical properties and plastic deformation mechanism of FeMnCoCrNi high entropy alloys

Zhang, H.F.; Yan, Haile; Yu, Hong; Ji, Zongwei; Hu, Qing‐Miao; Jia, Nan

doi:10.1016/j.jmst.2020.03.010

Cited by 34 publications

(7 citation statements)

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“…sprin ger. com/ journ al/ 40195. phase, such as CoCrNi [11,[17][18][19][20], CoVNi [16], FeCoCrNi [21], FeMnCoCr [8,[22][23][24][25] and FeMnCoCrNi [6,[26][27][28][29][30] alloys. Among them, the equiatomic FeMnCoCrNi alloy, also known as the Cantor alloy [2], is the earliest studied and the most representative fcc-structured HEA.…”

Section: Introductionmentioning

confidence: 99%

Orientation-Dependent Mechanical Responses and Plastic Deformation Mechanisms of FeMnCoCrNi High-entropy Alloy: A Molecular Dynamics Study

Zhang

Yan

Fang

et al. 2021

Acta Metall. Sin. (Engl. Lett.)

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Mechanical properties of high-entropy alloys (HEAs) with the face-centered cubic (fcc) structure strongly depend on their initial grain orientations. However, the orientation-dependent mechanical responses and the underlying plastic flow mechanisms of such alloys are not yet well understood. Here, deformation of the equiatomic FeMnCoCrNi HEA with various initial orientations under uniaxial tensile testing has been studied by using atomistic simulations, showing the results consistent with the recent experiments on fcc HEAs. The quantitative analysis of the activated deformation modes shows that the initiation of stacking faults is the main plastic deformation mechanism for the crystals initially oriented with [001], [111], and [112], and the total dislocation densities in these crystals are higher than that with the [110] and [123] orientations. Stacking faults, twinning, and hcp-martensitic transformation jointly promote the plastic deformation of the [110] orientation, and twinning in this crystal is more significant than that with other orientations. Deformation in the crystal oriented with [123] is dominated by the hcp-martensite transformation. Comparison of the mechanical behaviors in the FeMnCoCrNi alloy and the conventional materials, i.e. Cu and Fe 50 Ni 50 , has shown that dislocation slip tends to be activated more readily in the HEA. This is attributed to the larger lattice distortion in the HEA than the low-entropy materials, leading to the lower critical stress for dislocation nucleation and elastic-plastic transition in the former. In addition, the FeMnCoCrNi HEA with the larger lattice distortion leads to an enhanced capacity of storing dislocations. However, for the [001]-oriented HEA in which dislocation slip and stacking fault are the dominant deformation mechanisms, the limited deformation modes activated are insufficient to improve the work hardening ability of the material.

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Section: Introductionmentioning

confidence: 99%

Orientation-Dependent Mechanical Responses and Plastic Deformation Mechanisms of FeMnCoCrNi High-entropy Alloy: A Molecular Dynamics Study

Zhang

Yan

Fang

et al. 2021

Acta Metall. Sin. (Engl. Lett.)

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“…As shown in Fig. 1, the γ USF of FeMnCoCrNi is lower compared to that of FeCuCoCrNi and Cu, and accordingly, the energy barrier required for triggering the Shockley partials slip in the FeMnCoCrNi alloy is lower [53,54]. For FeCuCoCrNi and Cu, their critical stress for activating dislocations is close, since the USF of these materials is similar.…”

Section: Effect Of Sfe and Lattice Distortion On Deformation Mechanismmentioning

confidence: 89%

Reverse Transformation in [110]-Oriented Face-Centered-Cubic Single Crystals Studied by Atomic Simulations

Zhang

Yan

Fang

et al. 2022

Acta Metall. Sin. (Engl. Lett.)

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Bidirectional transformations, which are achieved by triggering both dynamic forward transformation from the face-centered-cubic (fcc) austenite to the hexagonal-close-packed (hcp) martensite and the reverse transformation from martensite to austenite during cold deformation, have been previously reported in FeMnCoCr-based high-entropy alloys (HEAs). This leads to the permanent refinement of microstructure and hence enhances the work-hardening capacity of alloys. In order to reveal the microscopic mechanism of the reverse transformation in HEAs under deformation, the effect of the sample aspect ratio, i.e., Z/X, on the evolution of deformation systems in the equi-atomic FeMnCoCrNi alloy with [110] orientation during uniaxial tensile loading along the Z direction is investigated by atomic simulations in this study. When the aspect ratio is 0.5, the reverse transformation is more significant compared with other models, while a good plasticity can still be maintained. We then compare the micromechanical behavior of three fcc single crystals, i.e., FeMnCoCrNi, FeCuCoCrNi, and pure Cu. The results show that the stacking fault energy plays a major role in the activation of different deformation mechanisms; however, the lattice distortion in the HEA does not significantly affect the activation of deformation systems. Furthermore, for all materials dislocation slip leads to the softening, while strain hardening is attributed to the initiation of multiple deformation mechanisms. The Shockley partials slip leads to bidirectional phase transition, twinning and detwinning in the three materials. Thus, the reverse transformation can occur in all metallic materials where the fcc to hcp phase transformation is the dominant deformation mechanism. These findings contribute to an in-depth understanding of the deformation mechanism in fcc-structured materials under severe plastic deformation and provide theoretical guidance for the design of alloys with superior strength-plasticity combinations.

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“…(1) Temperature: In the case of the CoCrNi alloy, the experimental measurement of SFE at RT yielded a value of 22 mJ•m -2 [32] . Many density functional theory calculations have shown that the SFE of the alloy at 0 K is negative [29,68,69] and it decreases with decreasing temperature. A low SFE is conducive to the formation of twins and phase transformation, thereby enhancing the properties of the alloy.…”

Section: Stacking Fault Energymentioning

confidence: 99%

“…Atomic simulations by Niu et al [69] showed that mixed and edge dislocations were unable to penetrate the nanotwin-HCP lamellae and instead forced to shear along with those features. This distributed the stress concentrations and promoted large hardening rates and ductility.…”

Section: Phase Transformation Stagementioning

confidence: 99%

A critical review of the mechanical properties of CoCrNi-based medium-entropy alloys

Xu¹,

Wang²,

Li³

et al. 2022

Microstructures

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The CoCrFeMnNi alloy is one of the most notable first-generation high-entropy alloys and is also known as a Cantor alloy. This alloy was first proposed in 2004 and shows promising performance at cryogenic temperatures (CTs). Subsequent research has indicated that the equiatomic ternary CoCrNi medium-entropy alloy (MEA), as a subset of the Cantor alloy family, has better mechanical properties than the CoCrFeMnNi alloy. Interestingly, both the strength and ductility of the CoCrNi MEA are higher at CTs than at room temperature. CoCrNi-based alloys have attracted considerable attention in the metallic materials community and it is therefore important to generalize and summarize the latest progress in CoCrNi-based MEA research. The present review initially briefly introduces the discovery of the CoCrNi MEA. Subsequently, its tensile response and deformation mechanisms are summarized. In particular, the effects of parameters, such as critical resolved shear stress, stacking fault energy and short-range ordering, on the deformation behavior are discussed in detail. The methods for strengthening the CoCrNi MEA are then reviewed and divided into two categories, namely, modifying microstructures and adjusting chemical compositions. In addition, the mechanical performance of CoCrNi-based MEAs, including their dynamic shear properties, creep behavior and fracture toughness, is also deliberated. Finally, the development prospects of CoCrNi-based MEAs are proposed.

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The effect of Co and Cr substitutions for Ni on mechanical properties and plastic deformation mechanism of FeMnCoCrNi high entropy alloys

Cited by 34 publications

References 50 publications

Orientation-Dependent Mechanical Responses and Plastic Deformation Mechanisms of FeMnCoCrNi High-entropy Alloy: A Molecular Dynamics Study

Orientation-Dependent Mechanical Responses and Plastic Deformation Mechanisms of FeMnCoCrNi High-entropy Alloy: A Molecular Dynamics Study

Reverse Transformation in [110]-Oriented Face-Centered-Cubic Single Crystals Studied by Atomic Simulations

A critical review of the mechanical properties of CoCrNi-based medium-entropy alloys

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