3D HR-EBSD Characterization of the plastic zone around crack tips in tungsten single crystals at the micron scale

Kalácska, Szilvia; Ast, Johannes; Ispánovity, Péter Dusán; Michler, Johann; Maeder, Xavier

doi:10.1016/j.actamat.2020.09.009

Cited by 38 publications

(16 citation statements)

References 46 publications

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“…Recently a new methodology of high (angular) resolution EBSD (HR-EBSD) has been established that is capable of determining the GND content to high precision on a surface of a single crystal using a cross-correlation based technique on the recorded Kikuchi patterns [22,23]. In addition, individual components of the dislocation density tensor, that characterizes GND density along with the average local Burgers vector direction, can also be obtained which helps in identifying activated slip planes in the crystal [24,25]. This method has been recently applied by Kalácska et al to investigate the dislocation structures developing in Cu micropillars oriented for multiple slip [26].…”

Section: Introductionmentioning

confidence: 99%

Microstructure evolution of compressed micropillars investigated by in situ HR-EBSD analysis and dislocation density simulations

Zoller¹,

Kalácska²,

Ispánovity³

et al. 2021

Comptes Rendus. Physique

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Section: Introductionmentioning

confidence: 99%

Microstructure evolution of compressed micropillars investigated by in situ HR-EBSD analysis and dislocation density simulations

Zoller¹,

Kalácska²,

Ispánovity³

et al. 2021

Comptes Rendus. Physique

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“…30 CC-EBSD has proved to be a powerful technique to investigate the crack propagation process. For example, Kalácska et al 31 investigated the shape of the plastic zone around crack tips in a W single crystal in terms of GNDs using CC-EBSD combined with focused ion beam (FIB) in three dimensions (i.e., 3D CC-EBSD), as shown in be higher than those inside the specimen at all three temperatures. However, the 3D shape of the plastic zone changes from being localized in front of the crack tip to butterfly-like distributions at higher temperature, which shields more efficiently the crack tip and consequently inhibits crack propagation.…”

Section: Strain and Dislocation Analysis By High Angularand Spatial-r...mentioning

confidence: 99%

Conditions near a crack tip: Advanced experiments for dislocation analysis and local strain measurement

Gammer

2022

MRS Bulletin

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The local stress state and microstructure near the crack-tip singularity control the fracture process. In ductile materials multiple toughening mechanisms are at play that dynamically influence stress and microstructure at the crack tip. In metals, crack-tip shielding is typically associated with the emission of dislocations. Therefore, to understand crack propagation on the most fundamental level, in situ techniques are required that are capable to combine imaging and stress mapping at high resolution. Recent experimental advances in x-ray diffraction, scanning electron microscopy, and transmission electron microscopy enable quantifying deformation stress fields from the bulk level down to the individual dislocation. Furthermore, through modern detector technology the temporal resolution has sufficiently improved to enable stress mapping during in situ experiments. Graphical abstract

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“…Two-dimensional EBSD studies, which are typically conducted, have the limitation that out-of-plane lattice rotation is generally not accessible. Combining EBSD with serial sectioning using a Focused Ion Beam (FIB) allows mapping the three-dimensional lattice rotation fields [14][15][16]. Alternatively, a two-dimensional deformation condition can be introduced deliberately to ensure that all out-of-plane components are zero, as employed to study cracks [17] and wedge indentation of fcc single crystals [18][19][20].…”

Section: Articlementioning

confidence: 99%

Size-dependent geometrically necessary dislocation structures in single-crystalline tungsten

Wang

Luan

Volz

et al. 2022

Journal of Materials Research

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Wedge indentation experiments were conducted to study the depth dependence of geometrically necessary dislocation (GND) structures in single-crystalline tungsten. Single-crystalline tungsten exhibits a pronounced indentation size effect (ISE), which can be rationalized based on GNDs. The dislocation mechanisms, however, are still under debate. Due to the plane strain condition during the wedge indentation, the dislocations in the cross sections underneath indents could be analyzed based on the Nye tensor and the lattice rotations determined using transmission Kikuchi diffraction. The dislocation structures depend on the size of the indent confirming the different hardness regimes and the bilinear ISE reported recently. For shallow indents, the dislocations are rather localized at the tip of the indent, while with increasing depth the dislocation volume expands; subgrains and distinct rays of increased dislocation density form. At larger depths, the indentation-induced deformation fields exhibit characteristics similar to the kink-type shear at a stationary crack tip. Graphical abstract

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3D HR-EBSD Characterization of the plastic zone around crack tips in tungsten single crystals at the micron scale

Cited by 38 publications

References 46 publications

Microstructure evolution of compressed micropillars investigated by in situ HR-EBSD analysis and dislocation density simulations

Microstructure evolution of compressed micropillars investigated by in situ HR-EBSD analysis and dislocation density simulations

Conditions near a crack tip: Advanced experiments for dislocation analysis and local strain measurement

Size-dependent geometrically necessary dislocation structures in single-crystalline tungsten

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