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Wzajemne oddziaływania bliźniaków odkształcenia w monokryształach Cu-8%at.Al

Szczerba M., Perek M.

Rudy i Metale Nieżelazne

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2005

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R. 50, nr 10-11

544-548

PL

Uzyskane w pracy niskotemperaturowe (77K) charakterystyki rozciągania silnie odkształconych monokryształów Cu-8%at.Al ujawniają istnienie istotnie różnych mechanizmów deformacji w zależności od wyjściowej orientacji krystalograficznej. Analiza figur biegunowych płaszczyzn {111} wykazuje, iż monokryształy rozciągane wzdłuż kierunku bliskiego [112] wykazują rozpad początkowej orientacji na co najmniej pięć nowych, podczas gdy te z okolicy środka trójkąta podstawowego, np. [1 4 5], rozpadają się tylko na trzy orientacje związane z obszarami osnowy oraz dwóch rodzin bliźniaków pierwszego rządu. Zasugerowano, że różnice w mechanizmach deformacji badanych monokryształów są silnie związane z naprężeniowo kontrolowanym procesem przecinania się bliźniaków odkształcenia.

EN

In the paper Iow temperature (77K) tensile characteristics of heavily deformed Cu-8at.%Al single crystals are presented, which document a strong correlation between the initial crystallographic orientation and a particular mechanism of crystal plastic deformation. On the basis of[l 11] pole figures measurements it is shown that the original lattice of single crystals with the tensile axis oriented close to the [11 2] direction is divided into at least five differently oriented regions, whereas that one of single crystals of the orientation located somewhere in the center of the basic stereographic triangle, e.g. [145], into three differently oriented crystal regions only. It is suggested that basic differences in the mechanisms of plastic deformation of the deformed single crystals are strongly connected with the stress controlled process of intersection of mechanical twins.

2

Generalized continuum with defects and asymmetric stresses

Boratyński W., Teisseyre R.

Acta Geophysica Polonica

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2004

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Vol. 52, nr 2

185-195

EN

Consistent theory is presented of continuum with defect distribution: dislocation and disclination densities and the densities of rotation nuclei of two kinds. Special attention is paid to rotation and twist motions, and the two approaches to the definition of the twist-bend tensor are combined. The elastic and self fields of stresses and strains become asymmetric, while the total fields remain symmetric as required by the compatibility conditions. However, the tensor of incompatibility becomes asymmetric. The dislocation-stress relations and the equations of motion for symmetric and asymmetric parts of stresses are given and the wave equations for spin and twist are derived. Some applications are shortly discussed.

3

Continuum with self-rotation nuclei: Evolution of defect fields and equations of motion

Teisseyre R., Boratyński W.

Acta Geophysica Polonica

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2002

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Vol. 50, nr 2

223-229

EN

Asymmetric theory of elastic continuum with dislocations, disclinations and nuclei of rotations is extended; we study the evolution and flow of the defect fields and arrive at the equations of motion for the symmetric and antisymmetric parts. The total fields can be represented by its elastic and self parts and the respective equations can be split into its self part prevailing on the fracture plane and into its total part describing seismic radiation field in a surrounding space. Special attention is paid to the rotation and twist motions.

4

Continuum with defect and self-rotation fields

Teisseyre R.

Acta Geophysica Polonica

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2002

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Vol. 50, nr 1

51-68

EN

An elastic continuum containing dense distribution of internal nuclei (dislocations, disclinations, vacancies, thermal nuclei, or electric nuclei) are the objects/sources creating internal stresses (self stresses). We consider the rotation and twist fields and the internal nuclei generating these fields; in general an asymmetry of some fields shall be taken into account. We present total, self and elastic fields and the related compatibility conditions; the stress-defect density relations arc derived, proving the validity of our approach. The examples of experimental results are given to indicate the possibilities of recording the rotation and twist effects.

5

Seismic rotation waves: dislocations and disclinations in a micromorphic continuum

Nagahama H., Teisseyre R.

Acta Geophysica Polonica

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2001

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Vol. 49, nr 1

119-129

EN

Deformation of the micromorphic structure (continuum) induces the appearance of dislocations and disclinations. These structural defects are related to anholonomity caused by microdisplacement tensor and moment of microstrains. In this study, two cases of incompatibility sources are considered: microdisplacements and ressions moments of microdisplacements. For these cases the expressions for twist-bend tensor are derived.

6

Gauge theory of dislocational electromagnetic field in earthquake preparation zone

Nagahama H.

Acta Geophysica Polonica

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2001

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Vol. 49, nr 4

437-448

EN

From the view point of the continuum theory of defects, we consider how the generated electromagnetic field can be related to the deformation field due to dislocations and disclinations. Based on the theory of connections in the higher-order space (Kawaguchi space), the Finsler deformation theory of ferromagnetic substances is introduced and the relation between this Finsler theory and the gauge theory of dislocations and disclinations is pointed out clearly. Moreover, the various preferred directions as internal degrees of freedom of each geomaterial point (e.g., polarization, spin moment, directors) of crystal materials (geomaterials) are discussed and the "exciting" state of these various preferred directions is regarded as the electromagnetic field radiation from an earthquake preparation zone.