Heterogeneous precipitation behavior and stacking-fault-mediated deformation in a CoCrNi-based medium-entropy alloy

Zhao, Yilu; Yang, Tao; Yang, Tong; Wang, J.; Luan, Junhua; Jiao, Zengbao; Chen, Da; Yang, Yanqing; Hu, Alice; Liu, C. T.; Kai, Ji‐Jung

doi:10.1016/j.actamat.2017.07.029

Cited by 700 publications

(201 citation statements)

References 45 publications

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“…Firstly, owing to the addition of 3 at% Al, 3 at% Ti elements, the solid-solution hardening can be estimated to be around 175 MPa [13,14]. Secondly, by accounting for the refined-grain strengthening effect, the yield stress of the alloy with mean grain size of 10 μm can be estimated by σ YS =σ 0 +kd −1/2 [15,16], in which σ 0 is the lattice friction (218 MPa for the CoCrNi alloy [17]); and K is the Hall-Petch constant (568 MPa/μm −1/2 for CoCrNi -AlTi alloy [18]) and d is the mean grain size. Based on the above calculation, the contribution to the yield stress from the refined-grain strengthening is determined to be about 390 MPa.…”

Section: Discussionmentioning

confidence: 99%

“…Based on the above calculation, the contribution to the yield stress from the refined-grain strengthening is determined to be about 390 MPa. Thirdly, the precipitation strengthening effect is ascribed mainly to the pronounced ordering strengthening of the γ′ particles, which can be calculated by !σ order =0.81 M(γ APB /2b)(3πf/8) 1/2 [19], where M is the Taylor factor (3.06 for the FCC polycrystalline matrix), γ APB is the antiphase boundaries energy of the nanoparticles (estimated to be 200 mJ m −2 ), b is the Burgers vector of the dislocation(∼0.254 nm), f is the volume fraction of precipitates (∼12±5%) [5,6,18]. Based on the above calculation, the contribution to the yield stress from the ordering strengthening of γ′ particles is determined to be 310 MPa.…”

Section: Discussionmentioning

confidence: 99%

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Superior strength-ductility combination of a Co-rich CoCrNiAlTi high-entropy alloy at room and cryogenic temperatures

Huo

Chang

et al. 2020

Mater. Res. Express

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In the present study, a Co-rich CoCrNi-AlTi high-entropy alloy was designed and fabricated by hot forging and 700°C for 8 h annealing process. The microstructure of the resultant alloy was composed of three multicomponent-phases with the face-centered cubic (FCC) structure, hexagonal closepacked (HCP) structure and L1 2 structure, respectively. The alloy exhibited a remarkable combination of tensile yield strength (gigapascal scale) and plasticity (uniform strain over 30%) at both room and cryogenic temperatures. The cooperative operation of multiple mechanisms consisting of refinedgrain strengthening, second-phase strengthening, precipitation strengthening, stacking faults and phase-transformation toughening was suggested to be responsible for the excellent mechanical response.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Superior strength-ductility combination of a Co-rich CoCrNiAlTi high-entropy alloy at room and cryogenic temperatures

Huo

Chang

et al. 2020

Mater. Res. Express

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“…The HEAs can be classified into three alloy families. These families include the transition metal HEAs (such as NiCoCrFeAlTi x [7] and (NiCoCr) 94 Al 3 Ti 3 [8]), the refractory metal HEAs (such as HfMo x NbTaTiZr [9] and NbTaWMoSi x [10]), and the light-weight metal HEAs (such as AlFeMgTiZn [11] and Al 7 CuMg 3 SnTiZn 7 [12]).…”

Section: Introductionmentioning

confidence: 99%

“…There are some transition metal HEAs which are designed to obtain coherent L1 2 precipitates (γ′ phase) via the addition of Al and Ti elements into the FCC matrix (γ phase), which always have good mechanical properties [8,[13][14][15][16][17][18]. Liu et al [13] studied the effect of Al addition on microstructure and mechanical properties of Ni 70−x Co 15 Cr 15 Al x .…”

Section: Introductionmentioning

confidence: 99%

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A new single crystal high entropy alloy with excellent high-temperature tensile property

Chen

Yuan

Ren

et al. 2020

Mater. Res. Express

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A new single crystal high entropy alloy is developed and produced using Bridgman directionalsolidification and seed-crystal method. The microstructure exhibits the directional dendrite morphology and is mainly composed of the FCC matrix and the L1 2 ordered precipitates. Its hightemperature yield strengths are far higher than those of the first-generation single crystal superalloys, and close to those of the second-generation ones. The solid-solution strengthening effect from the high content of W and Mo, as well as the precipitation strengthening effect from the combined addition of Al, Ti, Ta, and Nb, should be responsible for the excellent high-temperature strength of the investigated alloy.

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Numerical Simulation of Cold Spray Bonding for CrFeNi Medium‐Entropy Alloy

et al. 2022

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As a solid‐state deposition, cold spray maintains the intrinsic characteristics of the feedstock powder. Thus, it provides a unique opportunity for depositing high‐entropy alloys (HEAs) and medium‐entropy alloys (MEAs) that are of great interest for coatings to protect vulnerable materials from aggressive environments. However, considering the high hardness and the complexity of these powder's preparation, the choice of deposition parameters through experiments can be challenging and costly. Herein, a finite element model is presented to simulate the deposition of CrFeNi MEA using cold spray technology. A detailed approach is implemented to model the bonding of the particle to the substrate. The model is able to identify the deposition velocity window and simulate the metallurgical and mechanical interlocking. The particle adheres to the substrate at 500 m s−1 and pushes the substrate down facilitating mechanical interlocking. Furthermore, due to the strain localization induced by the particle, a notable temperature increase is observed at the substrate surface raising to its melting point in agreement with the ejecta eruption phenomenon. The developed numerical method can pave the way for successful experiments in case of costly HEAs and MEAs powders.

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Heterogeneous precipitation behavior and stacking-fault-mediated deformation in a CoCrNi-based medium-entropy alloy

Cited by 700 publications

References 45 publications

Superior strength-ductility combination of a Co-rich CoCrNiAlTi high-entropy alloy at room and cryogenic temperatures

Superior strength-ductility combination of a Co-rich CoCrNiAlTi high-entropy alloy at room and cryogenic temperatures

A new single crystal high entropy alloy with excellent high-temperature tensile property

Numerical Simulation of Cold Spray Bonding for CrFeNi Medium‐Entropy Alloy

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