Dislocations and grain size in ball-milled iron powder

Révész, Ádám; Ungár, Tamás; Borbély, András; Lendvai, J.

doi:10.1016/s0965-9773(96)00048-7

Cited by 193 publications

(64 citation statements)

References 15 publications

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“…Especially, in the Warren-Averbach procedure it was voluntarily suggested [1] [74], which, however, did not attract much attention until the eighties. Kuzel and Klimanek [75,76] and Ungár et al [77,78] have realized that strain anisotropy can be used to characterize the dislocation structure in more detail. In the modified Williamson-Hall plot [68,77] the FWHM or the integral breadths, DK FWHM or DK b , are scaled versus K 2 C C, where K ¼ 2 sin q/l, q is the diffraction angle and l is the wavelength of X-rays and C C is the avarage dislocation contrast factor, cf.…”

Section: Modified Williamson-hall Plot and Modified Warren-averbach Mmentioning

confidence: 99%

Characterization of defect structures in nanocrystalline materials by X-ray line profile analysis

Gubicza

Ungár

2007

Zeitschrift Für Kristallographie - Crystalline Materials

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Abstract. X-ray line profile analysis is a powerful alternative tool for determining dislocation densities, dislocation type, crystallite and subgrain size and size-distributions, and planar defects, especially the frequency of twin boundaries and stacking faults. The method is especially useful in the case of submicron grain size or nanocrystalline materials, where X-ray line broadening is a well pronounced effect, and the observation of defects with very large density is often not easy by transmission electron microscopy. The fundamentals of X-ray line broadening are summarized in terms of the different qualitative breadth methods, and the more sophisticated and more quantitative whole pattern fitting procedures. The efficiency and practical use of X-ray line profile analysis is shown by discussing its applications to metallic, ceramic, diamond-like and polymer nanomaterials.

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Section: Modified Williamson-hall Plot and Modified Warren-averbach Mmentioning

confidence: 99%

Characterization of defect structures in nanocrystalline materials by X-ray line profile analysis

Gubicza

Ungár

2007

Zeitschrift Für Kristallographie - Crystalline Materials

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“…The saturation of the crystallite size and the root mean square strain was also observed in Fe powder subjected to low-energy vibratory ball milling, cf. [60,61]. The steady-state crystallite size increases weakly with increasing milling temperature and decreases with increasing vibration amplitude.…”

Section: à2mentioning

confidence: 99%

Nanocrystalline materials studied by powder diffraction line profile analysis

Ungár¹,

Gubicza²

2007

Zeitschrift Für Kristallographie - Crystalline Materials

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Abstract. X-ray powder diffraction is a powerful tool for characterising the microstructure of crystalline materials in terms of size and strain. It is widely applied for nanocrystalline materials, especially since other methods, in particular electron microscopy is, on the one hand tedious and time consuming, on the other hand, due to the often metastable states of nanomaterials it might change their microstructures. It is attempted to overview the applications of microstructure characterization by powder diffraction on nanocrystalline metals, alloys, ceramics and carbon base materials. Whenever opportunity is given, the data provided by the X-ray method are compared and discussed together with results of electron microscopy. Since the topic is vast we do not try to cover the entire field.

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“…First, in ball-milled Fe, a standard WH analysis lead to very poor linear fits. [42] A modified WH analysis, taking into account peak broadening due to dislocations, made it possible to obtain fits of high quality and to extract grain size and dislocation density. The difficulty in this approach is that one has to assume a distribution of dislocations in terms of edge/screw character and Burgers vectors.…”

Section: Discussionmentioning

confidence: 99%

Cr-Mo solid solutions forced by high-energy ball milling

Hahn

Bellon

2004

Metall Mater Trans A

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Mixtures of Cr and Mo elemental powders, with the nominal compositions Cr 25 Mo 75 , Cr 50 Mo 50 , and Cr 75 Mo 25 , are processed by high-energy ball milling at ambient temperature. Milling is observed to force the mixing of the immiscible bcc elements Cr and Mo into solid solutions. The lattice parameter of these solid solutions, measured by X-ray diffraction (XRD), displays the expected positive deviation from Vegard's law. These deviations are compared to the ones predicted by Eshelby's inclusion model for dilute alloys. The conventional Williamson-Hall approach is shown to fail to determine the grain size in as-milled samples, probably due to the high density of dislocations. Annealing at 700°C for 10 hours under argon leads to a large reduction in structural defect density, without inducing any significant decomposition. The mixing measured in Cr-Mo is discussed in the broader context of the mechanical mixing forced by ball milling in moderately immiscible systems.

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Dislocations and grain size in ball-milled iron powder

Cited by 193 publications

References 15 publications

Characterization of defect structures in nanocrystalline materials by X-ray line profile analysis

Characterization of defect structures in nanocrystalline materials by X-ray line profile analysis

Nanocrystalline materials studied by powder diffraction line profile analysis

Cr-Mo solid solutions forced by high-energy ball milling

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