Relationships Between the Σ9 and Σ27 Boundaries and the Connectivity of Random Boundary in Hastelloy C-276 Alloy

Zhang, Xiaoyu; Xian-ming, Zhao; Li, Defu; Guo, Sheng

doi:10.1016/s1875-5372(18)30185-1

Cited by 4 publications

(3 citation statements)

References 23 publications

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“…Σ3 n (1 ≤ n ≤ 3) grain boundaries, including Σ3, Σ9, and Σ27, possess low energy and exhibit exceptional material properties [38,39]. The interactions among these boundaries may trigger the regeneration mechanism of Σ3 boundaries with a higher ratio of Σ(9 + 27)/Σ3 [40]. The proportion of Σ3 n grain boundaries before and after dynamic compression Deformation primarily relies on dislocation slip during plastic deformation.…”

Section: Dynamic Mechanical Propertiesmentioning

confidence: 99%

“…Correspondingly, the ratios of Σ(9 + 27)/Σ3 were 0.13, 0.18, and 0.23 at strain rates of 2100 s −1 , 3900 s −1 , and 5100 s −1 respectively. The lower ratio indicates poor interruption of random boundary networks [40], which suggests decreased connectivity and improved crack resistance. The twins can induce a reorientation effect and facilitate further slip in the alloy [43].…”

Section: Dynamic Mechanical Propertiesmentioning

confidence: 99%

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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%

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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“…It has been found that GB Σ3{112} may dissociate into two new interfaces, indicating 9 R phase formation on the GB [45], which is not considered in this work. Meanwhile, when annealing time is prolonged in GBE, both the Σ9 and Σ27 GBs are increased in percentage in Materials [46]. Therefore four symmetrically tilted GBs of Σ9 and Σ27 types are focused in this study and selected for computing diffusion in GBs.…”

Section: Introductionmentioning

confidence: 99%

Simulation of bulk and grain boundary diffusion phenomena in a high entropy CoCrFeMnNi alloy by molecular dynamics

Fan

Zhang²

2023

Phys. Scr.

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A series of calculations on the self-diffusion behavior of high entropy CoCrFeMnNi alloy were carried out using molecular dynamics methods. By computing both vacancy formation energy and atomic migration energy of the constituent elements in the alloy, the diffusional activation energy of each element is obtained, and the self-diffusion coefficients for bulk diffusion were calculated, with the values exhibiting close to of experiments. A model for structures of symmetrically tilted grain boundary is established, with Σ9 and Σ27 grain boundaries studied based on the coincidence site lattice theory. Measured by the full width at half maxima of the radial distribution function, it is found that the grain boundaries with low index are more ordered than those with high plane index, and the atom fluctuation occurred in the low-indexed grain boundaries is less intensively and sensitively to temperature change. Meanwhile, the diffusion coefficients of ordered grain boundaries are generally smaller than those of disordered grain boundaries. Compared with the experimental values of grain boundary diffusion, the diffusion activation energy of configured grain boundaries from coincidence site lattice is smaller than that of normal large-angle grain boundaries.

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Effect of hot rolling reduction and annealing treatment on grain boundary character distribution in austenitic low-density Fe-Mn-Al-C-Cr steel

Liu

Yang

et al. 2021

Materials Letters

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Relationships Between the Σ9 and Σ27 Boundaries and the Connectivity of Random Boundary in Hastelloy C-276 Alloy

Cited by 4 publications

References 23 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

Simulation of bulk and grain boundary diffusion phenomena in a high entropy CoCrFeMnNi alloy by molecular dynamics

Effect of hot rolling reduction and annealing treatment on grain boundary character distribution in austenitic low-density Fe-Mn-Al-C-Cr steel

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