Connections between the basal I1 “growth” fault and 〈c+a〉 dislocations

Agnew, Sean R.; Capolungo, Laurent; Calhoun, C.A.

doi:10.1016/j.actamat.2014.07.056

Cited by 97 publications

(35 citation statements)

References 44 publications

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“…Thus, our simulations confirm that the basal SFs can interact with dislocation slip and with other types of SFs and influence the mechanical properties of Mg alloys. Agnew et al [19] showed TEM observations of interactions between basal faults with the pyramidal dislocations. Sandlö bes et al [43] investigated the SFs in a rare-earth (RE) containing Mg alloy using TEM and density functional theory.…”

Section: Interactions Between the Basal Sfs And Dislocation Slipmentioning

confidence: 97%

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Non-equilibrium basal stacking faults in hexagonal close-packed metals

Zhang

Liu

2015

Acta Materialia

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Section: Interactions Between the Basal Sfs And Dislocation Slipmentioning

confidence: 97%

“…SFs in low symmetry, hexagonal-close-packed (HCP) structures are much more complex than those in cubic structures [13][14][15][16][17][18][19]. The complexity is manifested by the presence of multiple possible slip systems.…”

Section: Introductionmentioning

confidence: 99%

Non-equilibrium basal stacking faults in hexagonal close-packed metals

Zhang

Liu

2015

Acta Materialia

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“…[29,33] It was also shown that the stacking faults suppress dislocation slip and enhance dislocation accumulation. [34,35] It can be concluded that high fraction of LPSO phase (i.e., stacking faults) together with a low fraction of unrecrystallized grains are responsible for weak AE response in the WZ104 alloy.…”

Section: Discussionmentioning

confidence: 99%

Characterization of Microstructure and Mechanical Properties of Mg–Y–Zn Alloys with Respect to Different Content of LPSO Phase

et al. 2017

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The Mg-Y-Zn alloys with different contents of alloying elements are extruded at an extrusion ratio of 4:1 at 350 C. The microstructure of the alloys is of an inhomogeneous character showing fine grains produced due to dynamic recrystallization and coarse original grains elongated along the extrusion direction (ED). Moreover, Y and Zn form a long-period stacking-ordered (LPSO) phase whose volume fraction increases with their increasing content in the alloy. All investigated alloys exhibit distinct fiber textures with basal planes oriented parallel to ED. It is seen that increasing content of alloying elements leads to a weaker texture. Compression tests with concurrent acoustic emission (AE) measurements are performed along ED at room temperature and a constant strain rate in order to reveal active deformation mechanisms in the alloys and to relate them to their mechanical properties. The AE response is also discussed with respect to the volume fraction of the LPSO phase.

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“…Several hypothetical mechanisms have been proposed, such as a reaction between c and a 6 dislocations [33] and the emission of a partial from a vacancy/interstitial loop [34]. …”

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confidence: 99%

Novel Cross-Slip Mechanism of Pyramidal Screw Dislocations in Magnesium

et al. 2016

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Compared to cubic metals, whose primary slip mode includes twelve equivalent systems, the lower crystalline symmetry of hexagonal close-packed metals results in a reduced number of equivalent primary slips and anisotropy in plasticity, leading to brittleness at the ambient temperature.At higher temperatures, the ductility of hexagonal close-packed metals improves owing to the activation of secondary c+a pyramidal slip systems. Thus understanding the fundamental properties of corresponding dislocations is essential for the improvement of ductility at the ambient temperature. Here, we present the results of large-scale ab-initio calculations for c + a pyramidal screw dislocations in Mg and show that their slip behavior is a stark counterexample to the conventional wisdom that a slip plane is determined by the stacking fault plane of dislocations. A stacking fault between dissociated partial dislocations can assume a non-planar shape with a negligible energy cost and can migrate normal to its plane by a local shuffling of atoms. Partial dislocations dissociated on a {2112} plane "slither" in the {0111} plane, dragging the stacking fault with them in response to an applied shear stress. This finding resolves the apparent discrepancy that both {2112} and {0111} slip traces are observed in experiments while ab-initio calculations indicate that dislocations preferably dissociate in the {2112} planes.

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Connections between the basal I1 “growth” fault and 〈c+a〉 dislocations

Cited by 97 publications

References 44 publications

Non-equilibrium basal stacking faults in hexagonal close-packed metals

Non-equilibrium basal stacking faults in hexagonal close-packed metals

Characterization of Microstructure and Mechanical Properties of Mg–Y–Zn Alloys with Respect to Different Content of LPSO Phase

Novel Cross-Slip Mechanism of Pyramidal Screw Dislocations in Magnesium

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