About quantitative EBSD analysis of deformation and recovery substructures in pure Tantalum

Moussa, Charbel; Bernacki, Marc; Besnard, Rémy; Bozzolo, Nathalie

doi:10.1088/1757-899x/89/1/012038

Cited by 141 publications

(47 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…However, the KAM is sensitive to the size step (Moussa et al, 2015). In addition, the effect of noise on the GN dislocation density increases with decreasing the step size.…”

Section: Measurement Of the Gn Dislocation Densitymentioning

confidence: 99%

“… (n) is the plastic shear strain on the nth slip system. From the EBSD data, the GN dislocation density was calculated using the dislocation density tensor proposed by Nye (1953), the local misorientation angle, and so forth (Motz et al, 2005;Moussa et al, 2015). In this study, the local misorientation was used because it is easy to calculate.…”

Section: Measurement Of the Gn Dislocation Densitymentioning

confidence: 99%

“…The kernel average misorientation (KAM) is generally used to measure the local misorientation (Moussa et al, 2015). The KAM is the average misorientation angle of a given point with all of its neighbors (Sakakibara et al, 2010;Wright et al, 2011):…”

Section: Measurement Of the Gn Dislocation Densitymentioning

confidence: 99%

“…Electron backscatter diffraction (EBSD) is a microstructure observation technique that has rapidly progressed in recent years (Schwartz et al, 2009;Kamaya et al, 2005;Wilkinson and Britton, 2012;Yamagiwa et al, 2010;Hasunuma et al, 2015;Sakakibara et al, 2010;Nomura et al, 2012;Fujiyama et al, 2012;Wright et al, 2011). The GN dislocation density can be easily measured by EBSD (Calcagnotto et al, 2010;Moussa et al, 2015;Wright et al, 2015). Numerous studies have measured the GN dislocation density of indentation (Kysar et al, 2007;Demir et al, 2009;Rester et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Investigation of the indentation size effect based on measurement of the geometrically necessary dislocation density by electron backscatter diffraction

Hasunuma

Miyazaki

Shimada

et al. 2018

Mechanical Engineering Journal

View full text Add to dashboard Cite

In this study, we investigated the mechanism of the indentation size effect based on measurement of the geometrically necessary (GN) dislocation density. The GN dislocation density was measured around impressions by electron backscatter diffraction (EBSD). Indentation tests were performed for two types of single crystal Ni with different crystal orientations: (001) and (111). Difference between (111) and (001) orientation are small in the relationship of the hardness and the penetration depth. However, the deformation behavior and distribution of the GN dislocation density are different for the (001) and (111) orientations. For the (111) orientation, the GN dislocation density increases with decreasing hardness. However, the GN dislocation density for the (001) orientation increases with increasing hardness. The mechanism of the indentation size effect for the (001) orientation can be attributed to the increase of the GN dislocation density. In addition, we investigated the effect of the indenter shape on the indentation size effect. Indentation tests were performed with different apex angles. The hardness using an indenter with a large apex angle is smaller than that using an indenter with a small apex angle. The GN dislocation density increases with decreasing apex angle. The mechanism of the indentation size effect for the apex angle can be attributed to the increase of the GN dislocation density. We prepared another indenter with a dull tip. The hardness using the dull indenter is larger than that using the sharp indenter. The GN dislocation density distribution changes with the indenter sharpness but the GN dislocation density is similar. For the dull indenter, variation of the GN dislocation density has a smaller effect on the indentation size effect than the increase of the resistance because of the different indenter shape.

show abstract

“…However, the KAM is sensitive to the size step (Moussa et al, 2015). In addition, the effect of noise on the GN dislocation density increases with decreasing the step size.…”

Section: Measurement Of the Gn Dislocation Densitymentioning

confidence: 99%

Section: Measurement Of the Gn Dislocation Densitymentioning

confidence: 99%

Section: Measurement Of the Gn Dislocation Densitymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Investigation of the indentation size effect based on measurement of the geometrically necessary dislocation density by electron backscatter diffraction

Hasunuma

Miyazaki

Shimada

et al. 2018

Mechanical Engineering Journal

View full text Add to dashboard Cite

show abstract

“…La severidad de dichos gradientes, y por ende la heterogeneidad en la deformación plástica dentro de los granos, pueden determinarse a partir de varios parámetros [1,[15][16][17][18], entre los cuales uno de los más usados es la desorientación promedio en núcleos, KAM (Kernel Average Misorientation) [5,19]. Este índice, que resulta dependiente del tamaño de paso con el que se efectúa la medición [20,21], puede usarse para estimar densidad de dislocaciones geométricamente necesarias, compatible con el campo de tensiones presentes en el material [22,23]. Otro índice relacionado con la dispersión de orientaciones en el interior del grano es el GOS (Grain Orientation Spread); dicho parámetro ha sido estudiado por ALLAIN-BONASSO et al [1] analizando el comportamiento de GOS/D (donde D es el tamaño de grano).…”

unclassified

Gradientes de orientación en cercanías del borde de grano estudiados por EBSD

et al. 2018

View full text Add to dashboard Cite

RESUMENEl objetivo de este estudio es evaluar la desorientación local, su distribución y el gradiente de orientación en el desarrollo de la microestructura de una chapa de acero de calidad de embutido profundo (AKDQ). La microestructura se caracteriza con una resolución espacial a nivel de sub-grano usando difracción de electrones retrodifundidos (EBSD) en muestras sometidas a tensión uniaxial interrumpida en una probeta entallada y a solicitaciones típicas de procesos de conformado a través de ensayos Nakajima con diferentes geometrías de probeta. El empleo de la probeta entallada permite el estudio local de la evolución de la microestructura sobre un conjunto de granos identificables a medida que el material deforma, mientras las muestras correspondientes a los ensayos Nakajima se emplean para estudiar el comportamiento del gradiente de orientación con la distancia a los bordes de grano, bajo un enfoque estadístico. A partir de este último análisis se introducen dos nuevos parámetros basados en EBSD, llamados severidad promedio del gradiente (GAS) y espesor efectivo del borde (BET). En láminas de acero AKDQ de 0.67 mm de espesor, el valor del BET como indicador de la zona de influencia del BG resulta, en un sentido promedio, independiente del tamaño del grano y la condición de carga, sin superar los 3 μm. La severidad del gradiente muestra una buena correlación con la deformación plástica mesoscópica. Se observa además que la desorientación local se acumula en las proximidades de los bordes de grano mostrando diferencias en cada condición de carga.Palabras clave: Gradiente de orientación, EBSD, Deformación plástica, Chapa de acero AKDQ, condiciones de deformación en plano. ABSTRACTThe goal of this study is the evaluation of local misorientation, its distribution and orientation gradient in the microstructural development of a deep drawing quality steel sheet (AKDQ). The microstructure is characterized at sub-grain level spatial resolution using Electron Backscatter Diffraction (EBSD) in samples submitted to interrupted uniaxial tension in a notched sample and to typical solicitations in forming process through Nakajima tests with different sample geometries. The use of a notched sample allows performing a local study of the microstructural evolution in a set of identifiable grains as the material deforms, while the samples corresponding to Nakajima tests are used to study the behavior of the orientation gradient with the distance to the grain boundary under a statistical approach. From the latter analysis, two new EBSD-based parameters are introduced, named Gradient Average Severity (GAS) and Boundary Effective Thickness (BET). In 0.67 mm thick AKDQ steel sheets, the BET value as an indicator of GB influence zone is, in an average sense, independent on the grain size and the loading condition, below 3 μm. The gradient severity shows a good correlation with the mesoscopic plastic deformation. It is also observed that local misorientation accumulates in the grain boundary proximity, showing differences for each ...

show abstract

Crack‐Free Tungsten Fabricated via Laser Powder Bed Fusion Additive Manufacturing

Ramakrishnan,

Kumar,

Kumar

et al. 2023

Adv Funct Materials

View full text Add to dashboard Cite

Additive manufacturing of tungsten (W) is challenging due to its high melting point, high thermal conductivity, oxidation tendency, and brittleness from grain boundary (GB) oxides. In this study, the processing of W through laser powder bed fusion is investigated. Parts are fabricated under argon (Ar) and nitrogen (N2) atmospheres using the same processing parameters. The part produced in Ar has cracks with oxide precipitates decorating the fractured GBs. On the other hand, crack‐free W samples are produced under N2 atmosphere without any additional process modification. In both cases, the oxygen (O) content in the LPBF samples is similar to the starting powder. Interestingly, the analysis of the samples fabricated in nitrogen suggests that nitrogen is retained beyond the equilibrium solid solubility limit, while high‐resolution electron micrographs of fractured surfaces reveal reduced levels of oxides at GBs. Increased hardness for samples processed under N2 atmosphere is observed. Density Functional Theory (DFT) calculations performed to study the influence of interstitial nitrogen on oxygen diffusion in W indicated a hindrance to O diffusion from the presence of dissolved N.

show abstract

About quantitative EBSD analysis of deformation and recovery substructures in pure Tantalum

Cited by 141 publications

References 20 publications

Investigation of the indentation size effect based on measurement of the geometrically necessary dislocation density by electron backscatter diffraction

Investigation of the indentation size effect based on measurement of the geometrically necessary dislocation density by electron backscatter diffraction

Gradientes de orientación en cercanías del borde de grano estudiados por EBSD

Crack‐Free Tungsten Fabricated via Laser Powder Bed Fusion Additive Manufacturing

Contact Info

Product

Resources

About