Tensile deformation behavior and deformation twinning of an equimolar CoCrFeMnNi high-entropy alloy

Joo, Soo Hyun; Kato, Hidemi; Jang, Miso; Moon, Jongun; Tsai, Che-Wei; Yeh, Jien Wei; Kim, H. S.

doi:10.1016/j.msea.2017.02.043

Cited by 172 publications

(36 citation statements)

References 54 publications

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“…This process is particularly relevant during initial stages of deformation when the number of twins and the density of high-angle twin boundaries are the highest [13]. It is already established that mechanical twinning can occur in the CoCrFeNiMn alloy during plastic deformation at room temperature, however, the extent and the role of twinning in microstructure development remains quite debatable [11,12,27,28].…”

Section: Discussionmentioning

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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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: Discussionmentioning

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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“…The attractive properties of the alloy at cryogenic temperatures were ascribed to a synergy of different deformation mechanisms, including nanotwinning [12,13,22]. Meanwhile the contribution of nanotwinning to plastic deformation of the alloy at room temperature remains debatable [22][23][24][25].…”

Section: Introductionmentioning

confidence: 99%

Recrystallized microstructures and mechanical properties of a C-containing CoCrFeNiMn-type high-entropy alloy

Klimova

Shaysultanov

Chernichenko

et al. 2019

Materials Science and Engineering: A

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The effect of cold rolling to 80% thickness reduction and annealing at 973-1373 K for 1 h on the microstructure and mechanical properties of a C-containing CoCrFeNiMn high-entropy alloy was studied. Cold rolling significantly strengthened the alloy to the yield strength of 1310 MPa. Annealing at 973 K or 1073 K resulted in incomplete recrystallization of an fcc matrix and M 23 C 6-type carbide precipitations aligned with highly elongated grains/subgrains. Complete recrystallization occurred during annealing at 1173 − 1373 K. The ordered arrangement of the carbides was not observed after annealing at 1273 K or 1373 K. The volume fraction of carbides decreased with increasing the annealing temperature that can be reasonably described by a Thermo-Calc prediction. The coarsening behavior of the microstructure constituents was studied during isothermal annealing at 1173 K for 1-50 h. It was found that the grain growth and the particle coarsening can be expressed by power law functions of annealing time with grain/particle size exponents of about 2 and 3, respectively. An increase in the annealing temperature from 973 K to 1373 K led to a gradual softening of the alloy; the yield strength decreased from 870 MPa to 320 MPa, whereas total elongation increased from 24% to 47%, respectively. Contributions of various strengthening mechanisms into the overall strength of the alloy were discussed.

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“…The encouraging properties of the alloy at cryogenic temperature were mostly attributed to pronounced deformation nano-twinning promoting high strain hardening capacity [ 5 , 9 , 25 ]. However, there are still different opinions on relative contributions of dislocation slip and twinning during plastic deformation at room temperature [ 9 , 26 , 27 , 28 , 29 ].…”

Section: Introductionmentioning

confidence: 99%

Microstructure and Mechanical Properties Evolution of the Al, C-Containing CoCrFeNiMn-Type High-Entropy Alloy during Cold Rolling

et al. 2017

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The effect of cold rolling on the microstructure and mechanical properties of an Al- and C-containing CoCrFeNiMn-type high-entropy alloy was reported. The alloy with a chemical composition (at %) of (20–23) Co, Cr, Fe, and Ni; 8.82 Mn; 3.37 Al; and 0.69 C was produced by self-propagating high-temperature synthesis with subsequent induction. In the initial as-cast condition the alloy had an face centered cubic single-phase coarse-grained structure. Microstructure evolution was mostly associated with either planar dislocation glide at relatively low deformation during rolling (up to 20%) or deformation twinning and shear banding at higher strain. After 80% reduction, a heavily deformed twinned/subgrained structure was observed. A comparison with the equiatomic CoCrFeNiMn alloy revealed higher dislocation density at all stages of cold rolling and later onset of deformation twinning that was attributed to a stacking fault energy increase in the program alloy; this assumption was confirmed by calculations. In the initial as-cast condition the alloy had low yield strength of 210 MPa with yet very high uniform elongation of 74%. After 80% rolling, yield strength approached 1310 MPa while uniform elongation decreased to 1.3%. Substructure strengthening was found to be dominated at low rolling reductions (<40%), while grain (twin) boundary strengthening prevailed at higher strains.

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Tensile deformation behavior and deformation twinning of an equimolar CoCrFeMnNi high-entropy alloy

Cited by 172 publications

References 54 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

Recrystallized microstructures and mechanical properties of a C-containing CoCrFeNiMn-type high-entropy alloy

Microstructure and Mechanical Properties Evolution of the Al, C-Containing CoCrFeNiMn-Type High-Entropy Alloy during Cold Rolling

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