Evolution of the Entropy of Dislocation Structures with Strain in Solid Solutions of Cu-0.5at.% Al

The study on the evolution of the dislocation structure (DS) parameters with strain of solid solutions of Cu-0.5 at.% Al at different test temperatures has been carried out. It has been shown that in substructures with a disordered type of DS (disorder), the disordered mixtures with non-disoriented cells, as well as mixtures of non-disoriented and disoriented cellular structures, the entropy density increases with strain. It has been shown that formation of the cellular substructure corresponds to a diffuse kinetic phase transition of the 1-st kind in the DS. A jump-like decrease in entropy accompanying this phase transition is associated with the annihilation of dislocations in cellular walls and formation of excess dislocation density.

Download Full-text

Observations of dislocation interactions with recrystallized grain boundaries

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100105205 ◽

1988 ◽

Vol 46 ◽

pp. 628-629

Author(s):

C. W. Price

Keyword(s):

Dislocation Density ◽

Grain Boundary ◽

Strain Rate ◽

Grain Boundaries ◽

Dislocation Structure ◽

Hot Deformation ◽

Static Recrystallization ◽

High Dislocation Density ◽

High Angle ◽

Dislocation Interactions

Little evidence exists on the interaction of individual dislocations with recrystallized grain boundaries, primarily because of the severely overlapping contrast of the high dislocation density usually present during recrystallization. Interesting evidence of such interaction, Fig. 1, was discovered during examination of some old work on the hot deformation of Al-4.64 Cu. The specimen was deformed in a programmable thermomechanical instrument at 527 C and a strain rate of 25 cm/cm/s to a strain of 0.7. Static recrystallization occurred during a post anneal of 23 s also at 527 C. The figure shows evidence of dissociation of a subboundary at an intersection with a recrystallized high-angle grain boundary. At least one set of dislocations appears to be out of contrast in Fig. 1, and a grainboundary precipitate also is visible. Unfortunately, only subgrain sizes were of interest at the time the micrograph was recorded, and no attempt was made to analyze the dislocation structure.

Download Full-text

Heat transfer with kinetic phase transition in geomaterials

International Journal of Heat and Mass Transfer ◽

10.1016/j.ijheatmasstransfer.2020.120826 ◽

2021 ◽

Vol 167 ◽

pp. 120826

Author(s):

Zhiqiang Liu ◽

Danni Gong ◽

Linlin Wang

Keyword(s):

Heat Transfer ◽

Phase Transition ◽

Kinetic Phase Transition

Download Full-text

Gluodynamics and deconfinement phase transition under rotation from holography

Journal of High Energy Physics ◽

10.1007/jhep07(2021)132 ◽

2021 ◽

Vol 2021 (7) ◽

Author(s):

Xun Chen ◽

Lin Zhang ◽

Danning Li ◽

Defu Hou ◽

Mei Huang

Keyword(s):

Phase Transition ◽

Angular Velocity ◽

Chemical Potential ◽

Entropy Density ◽

Thermodynamic Quantities ◽

Strongly Coupled ◽

Trace Anomaly ◽

Holographic Qcd ◽

Deconfinement Phase Transition ◽

Small Chemical

Abstract We investigate rotating effect on deconfinement phase transition in an Einstein-Maxwell-Dilaton (EMD) model in bottom-up holographic QCD approach. By constructing a rotating black hole, which is supposed to be dual to rotating strongly coupled nuclear matter, we investigate the thermodynamic quantities, including entropy density, pressure, energy density, trace anomaly, sound speed and specific heat for both pure gluon system and two-flavor system under rotation. It is shown that those thermodynamic quantities would be enhanced by large angular velocity. Also, we extract the information of phase transition from those thermodynamic quantities, as well as the order parameter of deconfinement phase transition, i.e. the loop operators. It is shown that, in the T − ω plane, for two-flavor case with small chemical potential, the phase transition is always crossover. The transition temperature decreases slowly with angular velocity and chemical potential. For pure gluon system with zero chemical potential, the phase transition is always first order, while at finite chemical potential a critical end point (CEP) will present in the T − ω plane.

Download Full-text

Spontaneous phase transition from relaxor to macrodomain ferroelectric state in single-crystal PbSc0.5Nb0.5O3-BaSc0.5Nb0.5O3 solid solutions

Physics of the Solid State ◽

10.1134/1.1131185 ◽

2000 ◽

Vol 42 (1) ◽

pp. 161-164 ◽

Cited By ~ 23

Author(s):

I. P. Raevskii ◽

V. V. Eremkin ◽

V. G. Smotrakov ◽

E. S. Gagarina ◽

M. A. Malitskaya

Keyword(s):

Phase Transition ◽

Single Crystal ◽

Solid Solutions ◽

Ferroelectric State ◽

Spontaneous Phase

Download Full-text

Diffused phase transition boosted dye degradation with Ba (ZrxTi1−x)O3 solid solutions through piezoelectric effect

Nano Energy ◽

10.1016/j.nanoen.2021.106474 ◽

2021 ◽

Vol 89 ◽

pp. 106474

Author(s):

Mengde Zhu ◽

Siqi Li ◽

Hongfang Zhang ◽

Ju Gao ◽

K.W. Kwok ◽

...

Keyword(s):

Phase Transition ◽

Solid Solutions ◽

Piezoelectric Effect ◽

Dye Degradation ◽

Diffused Phase Transition

Download Full-text

Investigation of the influence of gradual substitution K ↔ Rb on the structure and phase transition in K x Rb1 − x Pb2Br5 solid solutions

Physics of the Solid State ◽

10.1134/s1063783409030251 ◽

2009 ◽

Vol 51 (3) ◽

pp. 589-592 ◽

Cited By ~ 4

Author(s):

L. I. Isaenko ◽

S. V. Mel’nikova ◽

A. A. Merkulov ◽

V. M. Pashkov ◽

A. Yu. Tarasova

Keyword(s):

Phase Transition ◽

Solid Solutions

Download Full-text

Deformed and stressed states of materials at the rolling of three layer stacks, dislocation structure of inner layer – nickel foil

Proceedings of the National Academy of Sciences of Belarus Physical-Technical Series ◽

10.29235/1561-8358-2021-66-3-270-279 ◽

2021 ◽

Vol 66 (3) ◽

pp. 270-279

Author(s):

L. I. Hurski

Keyword(s):

Dislocation Density ◽

Shear Deformation ◽

Dislocation Structure ◽

Three Dimensional ◽

Nickel Foil ◽

Dislocation Network ◽

Uniform Compression ◽

Degree Of Deformation ◽

Density Of Dislocations

The deformed and stressed states during rolling of a three-layer stack from various materials with a nickel foil inner layer are considered. The technique of determining the density of dislocations is described. The data about the inﬂuence of deformation conditions on the distribution and density of dislocations during rolling of nickel foil in various stacks are presented, including the registration or determination of the dislocation structure of nickel foil before deformation and at various degrees of deformation. It is shown that the mechanical scheme of deformation of the inner layer of the stack, namely, the deformation of the nickel foil by non-uniform compression with shear, has a decisive inﬂuence on the development of the dislocation structure and properties. It is established that the dislocation density is determined not only by the degree of deformation, but also by a scheme of the deformed and stressed state of matter, and for the case of shear deformation with increasing degree of deformation the dislocation density increases more rapidly than in the case of tensile strain or compression without shear; the result of shear deformation is a signiﬁcant reﬁnement of the structure of materials: with increasing degree of plastic deformation of the material a three-dimensional cellular network of dislocation is formed, wherein the borders of cells are formed by tangles of dislocations. With increasing degree of deformation, the density of dislocations at the cell boundaries increases, and the size of the cells decreases; in this case, the areas inside the cells of the dislocation network are always free of dislocations. The obtained results allow recommending the schemes with shear deformation for new promising processes of production of materials with unique properties.

Download Full-text

Растворимость теллура в кристаллах TlGaTe-=SUB=-2-=/SUB=-, TlInTe-=SUB=-2-=/SUB=- и электрофизические свойства твердых растворов

Физика твердого тела ◽

10.21883/ftt.2018.09.46380.331 ◽

2018 ◽

Vol 60 (9) ◽

pp. 1656

Author(s):

А.И. Наджафов ◽

Н.А. Алиева ◽

К.Г. Халилова

Keyword(s):

Phase Transition ◽

Electrical Conductivity ◽

Solid Solutions ◽

Physicochemical Analysis ◽

Lattice Parameters ◽

Temperature Dependences ◽

Complex Methods

AbstractThe complex methods of the physicochemical analysis are used to study TlGaTe_2–Te and TlInTe_2–Te alloys in which the tellurium solubility region up to 5.0 at % is observed. The temperature dependences of the lattice parameters and the electrical conductivity of TlGaTe_2 + x and TlInTe_2 + x have been studied in different crystallographic directions. The TlGaTe_2 + x and TlInTe_2 + x solid solutions undergo a phase transition at a temperature of 498 K. The transition nature is interpreted.

Download Full-text