Effect of cryo-deformation on structure and properties of CoCrFeNiMn high-entropy alloy

Stepanov, Nikita; Tikhonovsky, М.А.; Yurchenko, N.; Zyabkin, Dmitry; Klimova, M.; Zherebtsov, Sergey; Ефимов, А. А.; Салищев, Г. А.

doi:10.1016/j.intermet.2014.12.004

Cited by 364 publications

(155 citation statements)

References 35 publications

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“…For instance, the evolution of tensile properties during HPT had not been studied yet. Besides, considerably higher intensity of deformation twinning in the alloy at cryogenic temperature was observed during tension [6,11] or rolling [12]. Increased susceptibility to twinning can significantly accelerate the microstructure refinement, as it was shown earlier [12][13][14].…”

Section: Introductionmentioning

confidence: 77%

“…However, deformation twins are usually much thinner than annealing twins and intersect grains. The thickness of deformation twins in a single phase fcc microstructure is usually several tens of nanometers [12,21], whereas the thickness of annealing twins can reach several micrometers [22]. Some of the deformation twins are indicated with arrows in Figure 2b,c.…”

Section: Resultsmentioning

confidence: 99%

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Evolution of Microstructure and Mechanical Properties of a CoCrFeMnNi High-Entropy Alloy during High-Pressure Torsion at Room and Cryogenic Temperatures

Zherebtsov

Stepanov

Ivanisenko

et al. 2018

Metals

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High-pressure torsion (HPT) is applied to a face-centered cubic CoCrFeMnNi high-entropy alloy at 293 and 77 K. Processing by HPT at 293 K produced a nanostructure consisted of (sub)grains of~50 nm after a rotation for 180 • . The microstructure evolution is associated with intensive deformation-induced twinning, and substructure development resulted in a gradual microstructure refinement. Deformation at 77 K produces non-uniform structure composed of twinned and fragmented areas with higher dislocation density then after deformation at room temperature. The yield strength of the alloy increases with the angle of rotation at HPT at room temperature at the cost of reduced ductility. Cryogenic deformation results in higher strength in comparison with the room temperature HPT. The contribution of Hall-Petch hardening and substructure hardening in the strength of the alloy in different conditions is discussed.

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Section: Introductionmentioning

confidence: 77%

Section: Resultsmentioning

confidence: 99%

Evolution of Microstructure and Mechanical Properties of a CoCrFeMnNi High-Entropy Alloy during High-Pressure Torsion at Room and Cryogenic Temperatures

Zherebtsov

Stepanov

Ivanisenko

et al. 2018

Metals

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“…36,40,41,46 The prevalence of this twinning can be attributed to a particularly low stackingfault energy. 37,43,47,310 However, while the ductility increase with decreasing temperature can be readily interpreted, the temperature dependence of yield stress in this compositionally complex alloy, and other HEAs is less well understood.…”

Section: Improved Understandingmentioning

confidence: 99%

High-entropy alloys: a critical assessment of their founding principles and future prospects

Pickering

Jones

2016

International Materials Reviews

736

299

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High-entropy alloys (HEAs) are a relatively new class of materials that have gained considerable attention from the metallurgical research community over recent years. They are characterised by their unconventional compositions, in that they are not based around a single major component, but rather comprise multiple principal alloying elements. Four core effects have been proposed in HEAs: (1) the entropic stabilisation of solid solutions, (2) the severe distortion of their lattices, (3) sluggish diffusion kinetics and (4) that properties are derived from a cocktail effect. By assessing these claims on the basis of existing experimental evidence in the literature, as well as classical metallurgical understanding, it is concluded that the significance of these effects may not be as great as initially believed. The effect of entropic stabilisation does not appear to be overarching, insufficient evidence exists to establish the strain in the lattices of HEAs, and rapid precipitation observed in some HEAs suggests their diffusion kinetics are not necessarily anomalously slow in comparison to conventional alloys. The meaning and influence of the cocktail effect is also a matter for debate. Nevertheless, it is clear that HEAs represent a stimulating opportunity for the metallurgical research community. The complex nature of their compositions means that the discovery of alloys with unusual and attractive properties is inevitable. It is suggested that future activity regarding these alloys seeks to establish the nature of their physical metallurgy, and develop them for practical applications. Their use as structural materials is one of the most promising and exciting opportunities. To realise this ambition, methods to rapidly predict phase equilibria and select suitable HEA compositions are needed, and this constitutes a significant challenge. However, while this obstacle might be considerable, the rewards associated with its conquest are even more substantial. Similarly, the challenges associated with comprehending the behaviour of alloys with complex compositions are great, but the potential to enhance our fundamental metallurgical understanding is more remarkable. Consequently, HEAs represent one of the most stimulating and promising research fields in materials science at present.

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“…Among the HEAs, CrMnFeCoNi alloy stands out as a material exhibiting excellent low-temperature mechanical properties [15]. As reported in numerous publications [15,[17][18][19][20][21][22], this is commonly associated with deformation twinning, which causes changes in crystallographic plane orientation that restrict dislocation slip. Deformation twinning in CrMnFeCoNi alloy is generally believed to occur at room temperature, although this was questioned in some reports (cf.…”

Section: Introductionmentioning

confidence: 99%

“…[18]). Recent data [13,15,20,23] suggest that twins do occur at sufficiently high strains, when a critical stress for twinning in the alloy (e.g. 720 ± 30 MPa for the HEA reported in [24]) is reached.…”

Section: Introductionmentioning

confidence: 99%

Constitutive modeling of deformation behavior of high-entropy alloys with face-centered cubic crystal structure

Jang

Ahn

Moon

et al. 2017

Materials Research Letters

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A constitutive model based on the dislocation glide and deformation twinning is adapted to facecentered cubic high-entropy alloys (HEAs) as exemplified by the CrMnFeCoNi system. In this model, the total dislocation density is considered as the only internal variable, while the evolution equation describing its variation during plastic deformation is governed by the volume fraction of twinned material. The suitability of the model for describing the strain hardening behavior of HEAs was verified experimentally through compression tests on alloy CrMnFeCoNi and its microstructure characterization by electron backscatter diffraction and X-ray diffraction using synchrotron radiation. IMPACT STATEMENTWe adopted a constitutive model based on dislocation density and twin volume fraction evolution, to analyze the deformation behavior of the high-entropy alloy CrMnFeCoNi theoretically. ARTICLE HISTORY

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Effect of cryo-deformation on structure and properties of CoCrFeNiMn high-entropy alloy

Cited by 364 publications

References 35 publications

Evolution of Microstructure and Mechanical Properties of a CoCrFeMnNi High-Entropy Alloy during High-Pressure Torsion at Room and Cryogenic Temperatures

Evolution of Microstructure and Mechanical Properties of a CoCrFeMnNi High-Entropy Alloy during High-Pressure Torsion at Room and Cryogenic Temperatures

High-entropy alloys: a critical assessment of their founding principles and future prospects

Constitutive modeling of deformation behavior of high-entropy alloys with face-centered cubic crystal structure

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