Atomic-scale insight into interaction mechanism between screw dislocation and HCP phase in high-entropy alloy

Li, R. N.; Song, H.Y.; Xiao, Meixia; An, M.R.

doi:10.1063/5.0130784

Cited by 4 publications

(1 citation statement)

References 56 publications

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“…The experimental data in copper predominantly indicates that the dislocation drag mechanism acts as the rate-limiting factor above strain rates of 10 3 s −1 , while the flow stress is determined by the damping forces exerted by dislocations at high plastic strain rates [36]. Furthermore, molecular dynamics simulation is employed to investigate the interaction mechanism between screw dislocations and the HCP phase in FCC-structured CoCrFeMnNi HEAs [37]. The modes of interaction between dislocations and the HCP phase can be classified as penetration and absorption mechanisms, which are determined by factors such as the thickness of the HCP phase, strain rate, and temperature.…”

Section: Dynamic Mechanical Propertiesmentioning

confidence: 99%

Microstructure and Texture Evolution of a Dynamic Compressed Medium-Entropy CoCr0.4NiSi0.3 Alloy

Zhang,

Chen

et al. 2023

Crystals

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Focal research has been conducted on medium-entropy alloys (MEAs) that exhibit a balanced combination of strength and plasticity. In this study, the microstructure, dynamic mechanical properties, and texture evolution of an as-cast medium-entropy CoCr0.4NiSi0.3 alloy were investigated through dynamic compression tests at strain rates ranging from 2100 to 5100 s−1 using the Split Hopkinson Pressure Bar in order to elucidate the underlying dynamic deformation mechanism. The results revealed a significant strain rate effect with dynamic compressive yield strengths of 811 MPa at 2100 s−1, 849 MPa at 3000 s−1, 919 MPa at 3900 s−1, and 942 MPa at 5100 s−1. Grains were dynamically refined from 19.73 to 3.35 μm with increasing strain rates. The correlation between adiabatic temperature rise induced by dynamic compression and dynamic recrystallization was examined, revealing that the latter is not associated with adiabatic heating but rather with phase transition triggered by the dynamic stress during compression. The proportion of Σ3n (1 ≤ n ≤ 3) grain boundaries in deformation specimens increases with increasing strain rates during dynamic compression. The formation of specific three-node structures enhances both strength and plasticity by impeding crack propagation and resisting higher mechanical stress. In the as-cast state, significant anisotropy was observed in the MEA. As strain rates increased, it transited into a stable {111}<112> F texture. The exceptional dynamic properties of strength and plasticity observed in the as-cast state of the MEA can be attributed to a deformation mechanism involving a transition from dislocation slip to the formation of intricate arrangements, accompanied by interactions encompassing deformation nanotwins, stacking faults, Lomer–Cottrell locks, stair-rods, and displacive phase transformations at elevated strain rates.

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Section: Dynamic Mechanical Propertiesmentioning

confidence: 99%

Microstructure and Texture Evolution of a Dynamic Compressed Medium-Entropy CoCr0.4NiSi0.3 Alloy

Zhang,

Chen

et al. 2023

Crystals

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Effect of Twin Spacing and Loading Mode on Mechanical Properties and Deformation Mechanism of NiCoAl Columnar Polycrystalline Alloy

Zhang,

Lu,

Yang

et al. 2023

Physica Status Solidi (b)

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Grain boundary engineering is an effective and feasible metal strengthening strategy to enhance the properties of nanopolycrystalline alloys by changing the number, configuration, and connectivity of different types of grain boundaries, especially for the twin boundaries. In the present contribution, the effect of twin spacing and loading mode on the deformation behavior and mechanism of NiCoAl columnar polycrystalline alloy is investigated. The results show that the nanotwins can not only increase the bearing capacity of dislocations but also emit many dislocations, resulting in the coupling effect of dislocation strengthening and twin strengthening. When the twin spacing is large, intrinsic stacking faults occur and gradually transform into deformation twins. In this stage, Shockley partial dislocation controls plastic deformation. When the twin spacing is small, the high‐density twin layers and stacking faults are more likely to interweave, showing a combination action of Shockley partial dislocation and stair‐rod dislocation. With the loading changing to Z axis, the yield strength decreases due to reduced resistance to the dislocation and a weakened number of Shockley partial dislocations of the emission, leading to less strengthening of the twins. The insights provide a solid theoretical foundation for the further application of NiCoAl in industrial production.

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Study of phase transition and local order in equiatomic and nonequiatomic mixtures of HfNbTaTi under uniaxial loading from molecular dynamics simulations

Protim Hazarika,

Tripathi,

Nath Chakraborty

2024

Journal of Applied Physics

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We simulate an alloy of HfNbTaTi mixed in six different proportions and also of the equiatomic system under uniaxial tensile loading at 300 K. Molecular dynamics simulation trajectories are analyzed using radial distribution functions, OVITO, bond-orientational order parameters, and coordination numbers. Equiatomic and the two other alloys (Hf0.31Nb0.23Ta0.23Ti0.23 and Hf0.23Nb0.31Ta0.23Ti0.23) containing comparable fraction of elements deform similarly through the formation of an amorphous state. Two alloys rich in Nb (Hf0.17Nb0.50Ta0.16Ti0.17) and Ta (Hf0.17Nb0.16Ta0.50Ti0.17) deform similarly resulting in the formation of bcc atoms, which transform to fcc at higher loading. Finally, alloys rich in Hf (Hf0.50Nb0.16Ta0.17Ti0.17) and Ti (Hf0.17Nb0.16Ta0.17Ti0.50) deform resulting in high dislocation densities and hcp atoms. These two hcp-rich alloys also undergo strain hardening. In each mixture during loading, local orientational order of all the different elements changes similarly. Atoms prefer to pair with other atoms than to themselves during tensile loading.

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Atomic-scale insight into interaction mechanism between screw dislocation and HCP phase in high-entropy alloy

Cited by 4 publications

References 56 publications

Microstructure and Texture Evolution of a Dynamic Compressed Medium-Entropy CoCr0.4NiSi0.3 Alloy

Microstructure and Texture Evolution of a Dynamic Compressed Medium-Entropy CoCr0.4NiSi0.3 Alloy

Effect of Twin Spacing and Loading Mode on Mechanical Properties and Deformation Mechanism of NiCoAl Columnar Polycrystalline Alloy

Study of phase transition and local order in equiatomic and nonequiatomic mixtures of HfNbTaTi under uniaxial loading from molecular dynamics simulations

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