From diluted solid solutions to high entropy alloys: Saturation grain size and mechanical properties after high pressure torsion

Keil, Tom; Bruder, Enrico; Laurent‐Brocq, Mathilde; Durst, Karsten

doi:10.1016/j.scriptamat.2020.09.046

Cited by 15 publications

(7 citation statements)

References 28 publications

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“…The SRS exponent = d H d (ln ) (ln ) was determined using the SRJ tests at an indentation depth of 1500 nm, from 0.05 s −1 to 0.001 s −1 , similar to that previously reported [51]. From the SRJ tests, an m value of 0.0091 is obtained.…”

Section: Nanoindentation Strain Rate Jump Testingmentioning

confidence: 65%

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Computational and Experimental Investigation of the Strain Rate Sensitivity of Small Punch Testing of the High-Entropy Alloy Cocrfemnni

et al. 2022

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Section: Nanoindentation Strain Rate Jump Testingmentioning

confidence: 65%

“…where ρ = 7.9 kg/m 3 is the density, C p is the specific heat capacity ∼450 J/(kgK) for Cantor alloy [51] and parameter n is the strain hardening power index. The term ρC p n is the hardening component while dT is the competing thermal softening parameter.…”

Section: Transmission Electron Microscopymentioning

confidence: 99%

Computational and Experimental Investigation of the Strain Rate Sensitivity of Small Punch Testing of the High-Entropy Alloy Cocrfemnni

et al. 2022

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“…The grain size can be reduced until a certain value, the saturation grain size. The typical saturation grain size for alloys and HEAs reported in the literature is in the range of 50–100 nm [ 28 , 29 , 30 ]. Recently, the effect of the HPT process on the saturation grain size and mechanical properties has been investigated for the Cantor alloy system [ 29 , 30 ].…”

Section: Introductionmentioning

confidence: 99%

“…The typical saturation grain size for alloys and HEAs reported in the literature is in the range of 50–100 nm [ 28 , 29 , 30 ]. Recently, the effect of the HPT process on the saturation grain size and mechanical properties has been investigated for the Cantor alloy system [ 29 , 30 ]. In Reference [ 30 ] a single-phase nanocrystalline (grain size of 50 nm) CoCrFeNiMn alloy with few chromium oxide precipitates (of 7–10 nm) and high hardness of 6700 MPa has been produced by HPT.…”

Section: Introductionmentioning

confidence: 99%

Effect of High-Pressure Torsion on the Microstructure and Magnetic Properties of Nanocrystalline CoCrFeNiGax (x = 0.5, 1.0) High Entropy Alloys

et al. 2022

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In our search for an optimum soft magnet with excellent mechanical properties which can be used in applications centered around “electro mobility”, nanocrystalline CoCrFeNiGax (x = 0.5, 1.0) bulk high entropy alloys (HEA) were successfully produced by spark plasma sintering (SPS) at 1073 K of HEA powders produced by high energy ball milling (HEBM). SPS of non-equiatomic CoCrFeNiGa0.5 particles results in the formation of a single-phase fcc bulk HEA, while for the equiatomic CoCrFeNiGa composition a mixture of bcc and fcc phases was found. For both compositions SEM/EDX analysis showed a predominant uniform distribution of the elements with only a small number of Cr-rich precipitates. High pressure torsion (HPT) of the bulk samples led to an increased homogeneity and a grain refinement: i.e., the crystallite size of the single fcc phase of CoCrFeNiGa0.5 decreased by a factor of 3; the crystallite size of the bcc and fcc phases of CoCrFeNiGa—by a factor of 4 and 10, respectively. The lattice strains substantially increased by nearly the same extent. After HPT the saturation magnetization (Ms) of the fcc phase of CoCrFeNiGa0.5 and its Curie temperature increased by 17% (up to 35 Am2/kg) and 31.5% (from 95 K to 125 K), respectively, whereas the coercivity decreased by a factor of 6. The overall Ms of the equiatomic CoCrFeNiGa decreased by 34% and 55% at 10 K and 300 K, respectively. At the same time the coercivity of CoCrFeNiGa increased by 50%. The HPT treatment of SPS-consolidated HEAs increased the Vickers hardness (Hv) by a factor of two (up to 5.632 ± 0.188) only for the non-equiatomic CoCrFeNiGa0.5, while for the equiatomic composition, the Hv remained unchanged (6.343–6.425 GPa).

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“…What's more, some deformation-induced twins were observed as the tensile test was interrupted after more than 20% strain when the test temperature was lower from 20 • C to −196 • C. Yong et al [8] proposed that the separation of nanoscale phase could significantly promote the yield strength of Mn-Fe-Co-Ni-Cu alloy. Keil et al [9] systematically researched the equiatomic composition for mechanical properties optimum of (Cr-Mn-Fe-Co)x-Ni1-x and quantitatively investigated the saturation grain size, hardness and strain rate sensitivity with the variation of Ni element composition.…”

Section: Introductionmentioning

confidence: 99%

High Temperature Oxidation Behavior of an Equimolar Cr-Mn-Fe-Co High-Entropy Alloy

et al. 2021

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The oxidation behavior of an equimolar Cr-Mn-Fe-Co high-entropy alloy (HEA) processed by 3D laser printing was investigated at 700 °C and 900 °C. The oxidation kinetics of the alloy followed the parabolic rate law, and the oxidation rate constant increased with the rising of the temperature. Inward diffusion of oxygen and outward diffusion of cations took place during the high-temperature oxidation process. A spinel-type oxide was formed on the surface, and the thickness of the oxide layer increased with the rising of experimental temperature or time. The exfoliation of the oxide layer took place when the test was operated at 900 °C over 12 h. During oxidation tests, the matrix was propped open by oxides and was segmented into small pieces. The formation of loose structures had great effects on the high-temperature oxidation resistance of the HEA.

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From diluted solid solutions to high entropy alloys: Saturation grain size and mechanical properties after high pressure torsion

Cited by 15 publications

References 28 publications

Computational and Experimental Investigation of the Strain Rate Sensitivity of Small Punch Testing of the High-Entropy Alloy Cocrfemnni

Computational and Experimental Investigation of the Strain Rate Sensitivity of Small Punch Testing of the High-Entropy Alloy Cocrfemnni

Effect of High-Pressure Torsion on the Microstructure and Magnetic Properties of Nanocrystalline CoCrFeNiGax (x = 0.5, 1.0) High Entropy Alloys

High Temperature Oxidation Behavior of an Equimolar Cr-Mn-Fe-Co High-Entropy Alloy

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