Orientation and temperature dependence of a planar slip and twinning in single crystals of Al0.3CoCrFeNi high-entropy alloy

Киреева, И. В.; Chumlyakov, Yu. I.; Pobedennaya, Z. V.; Vyrodova, A.V.; Kuksgauzen, Irina; Kuksgauzen, D. A.

doi:10.1016/j.msea.2018.09.025

Cited by 36 publications

(22 citation statements)

References 46 publications

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“…The lower the SFE is, the more easily deformation twinning is activated. Al 0.3 CrFeCoNi has a relatively low SFE of 51 mJ m -2 [39,40]. Previous experimental studies have shown that deformation twinning is prevalent during compression of the Al 0.3 CrFeCoNi bulk sample [40].…”

Section: Tem Observation Of the Deformed Nanopillarsmentioning

confidence: 97%

Dynamic recrystallization-induced temperature insensitivity of yield stress in single-crystal Al1.2CrFeCoNi micropillars

Huang

Zhang

et al. 2020

Sci. China Technol. Sci.

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High-entropy alloys, a new class of metallic materials, exhibit excellent mechanical properties at high temperatures. In spite of the worldwide interest, the underlying mechanisms for temperature dependence of mechanical properties of these alloys remain poorly understood. Here, we systemically investigate the mechanical behaviors and properties of Al 1.2 CrFeCoNi (comprising a body-centered cubic phase) and Al 0.3 CrFeCoNi (comprising a face-centered cubic phase) single-crystal micropillars with three orientations ([100], [110], and [111]) at temperatures varying from 300 to 675 K by using in situ compression of micropillars inside a scanning electron microscope. The results show that the yield stresses of Al 1.2 CrFeCoNi micropillars are insensitive to temperature changes, and their flow stresses and work hardening rates increase slightly with increasing temperature from 300 to 550 K, which differs from the typical temperature dependence of yield/flow stresses in metals and alloys. In contrast, Al 0.3 CrFeCoNi micropillars exhibit typical thermal softening. Furthermore, it is found that the Al 1.2 CrFeCoNi micropillars exhibit a transition from homogenous deformation to localized deformation at a critical temperature, while the Al 0.3 CrFeCoNi micropillars always maintain a well-distributed and fine slip deformation. Detailed transmission electron microscopy analyses reveal that dynamic recrystallization (involving dislocation tangles, and formation of dislocation cell structures and sub-grains) plays a key role in the observed temperature insensitivity of the yield stress and increasing flow stress (and work hardening rate) with increasing temperature in the Al 1.2 CrFeCoNi micropillars, and that thermally activated dislocation slip leads to thermal softening of the Al 0.3 CrFeCoNi micropillars. The differences in deformation modes and temperature dependence of the mechanical properties between Al 1.2 CrFeCoNi and Al 0.3 CrFeCoNi essentially originate from the differences in dislocation activities and slip systems since the two alloys adopt different phases. Our findings provide key insights in the temperature dependence of mechanical properties and deformation behaviors of high-entropy alloys with body-centered cubic and face-centered cubic phases.

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Section: Tem Observation Of the Deformed Nanopillarsmentioning

confidence: 97%

Dynamic recrystallization-induced temperature insensitivity of yield stress in single-crystal Al1.2CrFeCoNi micropillars

Huang

Zhang

et al. 2020

Sci. China Technol. Sci.

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“…Table 1 presents the components  S and  G in (CoCrFeNi) 94 Ti 2 Al 4 according to Fig. 1a Thus, the effect of solid solution hardening with Ti and Al atoms, which are larger in radius than the others, shows up as an increase in  S due to their interaction with glide dislocations a/2110 [4,10,14]. When -phase nanoparticles precipitate in the (CoCrFeNi) 94 Ti 2 Al 4 crystals, the component  S remains invariant, the component  G grows, and the ratio  S / G decreases.…”

Section: Temperature Dependence Of Critical Shearmentioning

confidence: 99%

“…As a result, not only the stress  0.1 at above 296 K can be increased but its temperature dependence can be weakened. Third, compared to (CoCrFeNi) 93 Al 7 with a stacking fault energy of 0.051 J/m 2 [4,12], (CoCrFeNi) 94 Ti 2 Al 4 is lower in Al content and hence in stacking fault energy, and this increases its capacity for twinning at slip strains smaller than those in (CoCrFeNi) 93 Al 7 [4].…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…High-entropy fcc alloys are of interest due to their fast strain hardening, good plasticity and capability for ductile fracture particularly at cryogenic temperatures [1][2][3][4][5]. However, at above T = 296 K, the yield stress  0.1 in these alloys is low [3][4][5], and methods of increasing  0.1 are needed to extend their practical application. Among such methods can be, for example, grain refinement, solid solution hardening with interstitial atoms (nitrogen, carbon) or substitutional atoms of larger radius, and dispersion hardening [3,4,[6][7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

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Mechanical Behavior of Differently Oriented (CoCrFeNi)94Ti2Al4 Single Crystals

et al. 2021

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The paper analyzes the mechanical behavior and plastic deformation mechanisms (slip, twinning) in single-crystalline high-entropy fcc alloy (CoCrFeNi) 94 Ti 2 Al 4 (at %) in relation to the crystal orientation ([144] , [001]), type of deformation (tension, compression), and heat treatment (quenching, aging at 923 K for 4 h). The analysis shows that after aging at 923 K for 4 h, compared to quenching, the critical shear stress of such crystals increases by 20-30 MPa at 77-973 K due precipitated -phase particles of size 3-5 nm. The onset of their plastic flow, irrespective of the heat treatment, is associated with slip such that their critical shear stress depends neither on the crystal orientation nor on the type of deformation (tension, compression) at 77-973 K. When deformed at 77-973 K after quenching or aging, the [144] and [001] crystals reveal a planar structure with dislocation pileups. In the quenched and aged [144] crystals, twinning occurs after previous tensile slip deformation to 40% at 77 K. The stages of flow curves, the strain hardening coefficient, and the plasticity of the crystals are found to depend on their orientation, test temperature, and heat treatment. The dependences of the strain hardening coefficient of the crystals on their orientation and temperature in tension are discussed. A method is proposed for attaining a high yield strength in single-crystalline highentropy (CoCrFeNi) 94 Ti 2 Al 4 under tension at above 296 K.

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Effects of Ti addition and annealing on microstructure and mechanical properties of CoCrFeMnNi high-entropy alloy

Chen,

Hsueh

2024

J Mater Sci

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Orientation and temperature dependence of a planar slip and twinning in single crystals of Al0.3CoCrFeNi high-entropy alloy

Cited by 36 publications

References 46 publications

Dynamic recrystallization-induced temperature insensitivity of yield stress in single-crystal Al1.2CrFeCoNi micropillars

Dynamic recrystallization-induced temperature insensitivity of yield stress in single-crystal Al1.2CrFeCoNi micropillars

Mechanical Behavior of Differently Oriented (CoCrFeNi)94Ti2Al4 Single Crystals

Effects of Ti addition and annealing on microstructure and mechanical properties of CoCrFeMnNi high-entropy alloy

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