Plastic deformation of nickel under high hydrostatic pressure

Zehetbauer, M.; Kohout, Jan; Schafler, Erhard; Sachslehner, F.; Dubravina, Anna

doi:10.1016/j.jallcom.2004.01.039

Cited by 65 publications

(33 citation statements)

References 16 publications

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“…2b. The increase of dislocation density is in agreement with positron annihilation studies mentioned below (seen in a chapter 3.2.2) and in previous SPD studies [28,32]. These dislocation walls usually enclose several cells and are classified as geometrically necessary boundaries, since they participate in accommodation of lattice rotations in the adjoining volume [33].…”

Section: Mechanical Properties and Microhardnesssupporting

confidence: 90%

Relation between microstructural features and mechanical properties in oxygen free high conductivity copper after Equal-Channel Angular Pressing

KVACKAJ¹,

KOVÁČOVÁ²,

KOČIŠKO³

et al. 2021

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An oxygen free high conductivity (OFHC) copper was subjected to maximum 13 ECAP passes to achieve a sufficiently high degree of deformation. Strength properties (yield stress and ultimate tensile strength) show obvious increase up to the 4 th pass. In the 6 th ECAP pass, the yield stress and ultimate tensile strength are stabilized at a maximum of 449 MPa. Microstructure studies showed that the 1 st ECAP pass caused a significant increase of dislocation density. These dislocations are arranged in cells, forming dense dislocation walls at low-angle subgrains. After the 5 th ECAP pass, well-defined equiaxed ultrafine grains of diameter approximately 500 nm had emerged forming high-angle grain boundaries. The defect density studies carried out by positron annihilation spectroscopy method revealed an increase in a defect density (vacancies, dislocations) up to the 4 th pass, consequently with number of ECAP passes increasing, decrease in defects density (seen by positrons) was observed.K e y w o r d s : dislocation, grain boundaries, equiaxed ultrafine grained microstructure, electron microscopy, Equal Channel Angular Pressing (ECAP)

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Section: Mechanical Properties and Microhardnesssupporting

confidence: 90%

Relation between microstructural features and mechanical properties in oxygen free high conductivity copper after Equal-Channel Angular Pressing

KVACKAJ¹,

KOVÁČOVÁ²,

KOČIŠKO³

et al. 2021

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“…In the case of bulk ultra-fine grained materials formed by SPD methods, however, the X-ray size values are usually smaller than the TEM data, cf. [69,80,81,128]. The arrangement of dislocations into small angle grain boundaries provide a simple and straightforward model for subgrain/cell structure where the TEM grain size is obviously larger than the X-ray subgrain/cell size, as shown schematically in [129] and [83].…”

Section: The Interpretation Of Coherently Scattering Domains As Subgrmentioning

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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“…The most popular techniques are equal channel angular pressing (ECAP) and high pressure torsion (HPT), where polycrystalline metals are typically used as starting materials [1,2]. In the polycrystalline aggregate the individual crystallites are affected differently when they are subjected to plastic shear strain, i. e. a crystallite of the aggregate deforms against the resistance of the adjacent grains.…”

mentioning

confidence: 99%