Transition of twinning behavior in CoCrFeMnNi high entropy alloy with grain refinement

Sun, Shijie; Tian, Yanzhong; Lin, Hao-Hsiung; Yang, H.J.; Dong, Xianping; Wang, Y.H.; Zhang, Z.F.

doi:10.1016/j.msea.2017.12.022

Cited by 253 publications

(43 citation statements)

References 27 publications

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“…The average shear strengths of the joints brazed with BNi-2 filler metal at 1020 °C for 180 s, 300 s, and 600 s and at 1050 °C for 600 s are 193, 305, 310 and 319 MPa, respectively. Yield strength of annealed CoCrFeMnNi HEA at room temperature is strongly related to its grain size, and the Hall-Petch relationship is fitted well from the ultrafine-grained regime to the coarse-grained regime [ 20 , 21 ]. The grain size of CoCrFeMnNi HEA is approximately 30~100 μm, which belongs to the category of coarse grained region.…”

Section: Resultsmentioning

confidence: 99%

“…The grain size of CoCrFeMnNi HEA is approximately 30~100 μm, which belongs to the category of coarse grained region. The yield strength of CoCrFeMnNi HEA at room temperature with the grain size of 30–100 μm is between 200–250 MPa depending on the thermal history of the alloy [ 20 , 21 , 22 , 23 ]. Based on the von Mises criterion, the ratio between shear strength and tensile yield strength is 0.577, (1/

) [ 24 ].…”

Section: Resultsmentioning

confidence: 99%

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Infrared Brazing of CoCrFeMnNi Equiatomic High Entropy Alloy Using Nickel-Based Braze Alloys

Lin

Shiue

et al. 2019

Entropy

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Infrared vacuum brazing of CoCrFeMnNi high entropy alloy (HEA) using BNi-2 and MBF601 fillers has been investigated. Both brazes show poor wettability at temperatures only 20 °C above their liquidus temperatures. However, the wettability of BNi-2 and MBF601 fillers on CoCrFeMnNi HEA is greatly improved with increasing the test temperatures, 50 °C above their liquidus temperatures. The BNi-2 brazed joints are dominated by Ni-rich matrix with huge CrB and a few tiny boride precipitates. Average shear strengths of joints increase with increasing brazing temperature and/or time, and fracture location changes from blocky CrB in the brazed zone to grain boundary boride in the substrate. The MBF601 brazed joints are composed of CoCrFeMnNi-based matrix, particles of B/Co/Cr/Fe/Mn/Ni/P compounds, and some phosphides form along the grain boundaries of the substrate. The specimen brazed with MBF601 filler foil at 1050 °C for 600 s has the highest average shear strength of 321 MPa, while that brazed at 1080 °C for 600 s has a lower average shear strength of 271 MPa due to the presence of solidification shrinkage voids.

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Section: Resultsmentioning

confidence: 99%

) [ 24 ].…”

Section: Resultsmentioning

confidence: 99%

Infrared Brazing of CoCrFeMnNi Equiatomic High Entropy Alloy Using Nickel-Based Braze Alloys

Lin

Shiue

et al. 2019

Entropy

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“…However, it should be noted that the critical twin stress values of only about 450 MPa to 500 MPa, as stated in Refs. [19,20], seem to be unrealistic. In the case of the current tensile tests, stress increases from about 500 MPa up to the interruption point, corresponding to about 25 % additional straining.…”

Section: Initiation Of the Work-hardening Plateaumentioning

confidence: 99%

“…They reveal = 460 MPa ( = 153 MPa) for deformation twinning under tensile load along a 〈111〉direction at 77 K. Considering the relevant constraints for the appearance of mechanical twins in polycrystals, Sun et al [20] report a critical twinning stress of the order of 500 MPa for CoCrFeMnNi for a grain size in the range of 10 to 100 µm at room temperature. Evidently, there is no consistent trend of critical twinning stress observed in literature for this alloy so far.…”

Section: Introductionmentioning

confidence: 99%

Peculiarities of deformation of CoCrFeMnNi at cryogenic temperatures

et al. 2018

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“…Some earlier reports demonstrated promising mechanical characteristics of the equiatomic CoCrFeNiMn alloy with the ultrafinegrained (UFG) structure (d ≈ 0.5 µm) [37,38]. In these works cold working followed by annealing at temperatures ≥ 650°C was used to produce the UFG structure.…”

Section: Introductionmentioning

confidence: 99%

Mechanical properties of a new high entropy alloy with a duplex ultra-fine grained structure

Stepanov

Shaysultanov

Chernichenko

et al. 2018

Materials Science and Engineering: A

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A new approach to increase the tensile performance of high entropy alloys (HEAs) by producing a duplex ultrafine-grained (UFG) structure was reported in this work. A novel HEA based on the CoCrFeNiMn system with substantial amounts of Al and C was used for the illustration of this approach. In the as-cast condition the alloy had almost entirely a single face-centered cubic (fcc) phase structure with an insignificant amount of M 23 C 6 carbides. After cold rolling and annealing at 800-1000°C an increased amount of fine second phases, namely M 23 C 6 carbides and B2 phase, effectively pinned boundaries of recrystallized fcc grains. As a result, a duplex UFG structure composed of the recrystallized fcc grains and M 23 C 6 and B2 particles was produced. The alloy with the UFG structure demonstrated attractive mechanical properties. For example, after annealing at 900°C the alloy had the yield strength of 785 MPa, the ultimate tensile strength of 985 MPa, and elongation to fracture of 32%. The phase composition of the alloy in different conditions was compared with the equilibrium phase diagram obtained using a Thermo-Calc software. Strengthening mechanisms were qualitatively analyzed, and some possibilities for further improvement of strength of the alloy were discussed.

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Transition of twinning behavior in CoCrFeMnNi high entropy alloy with grain refinement

Cited by 253 publications

References 27 publications

Infrared Brazing of CoCrFeMnNi Equiatomic High Entropy Alloy Using Nickel-Based Braze Alloys

Infrared Brazing of CoCrFeMnNi Equiatomic High Entropy Alloy Using Nickel-Based Braze Alloys

Peculiarities of deformation of CoCrFeMnNi at cryogenic temperatures

Mechanical properties of a new high entropy alloy with a duplex ultra-fine grained structure

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