Analysis of Data on the Evolution of the Dislocation Structure of Nanostructured Zirconium Obtained by the Low-temperature Acoustic Technique

2021 ◽  
pp. 70-90
Author(s):  
P. P. Pal-Val ◽  
A. P. Rybalko ◽  
L. N. Pal-Val ◽  
E. N. Vatazhuk
Keyword(s):  
Low Temperature ◽  
Dislocation Structure ◽  
Acoustic Technique

Dislocation structure formation in SiGe/Si(001) heterostructures with low-temperature buffer layers

2002 ◽  
Vol 14 (48) ◽  
pp. 13313-13318 ◽  
Author(s):  
V I Vdovin ◽  
M M hlberger ◽  
M M Rzaev ◽  
F Sch ffler ◽  
T G Yugova
Keyword(s):  
Low Temperature ◽  
Structure Formation ◽  
Dislocation Structure ◽  
Buffer Layers

Structure of Deformed Iron: Irradiation Softening and Orientation Dependence

1975 ◽  
Vol 33 ◽  
pp. 168-169
Author(s):  
Johsei Nagakawa ◽  
A. Sato ◽  
M. Meshii
Keyword(s):  
Solid Solution ◽  
Plastic Deformation ◽  
Low Temperature ◽  
Dislocation Structure ◽  
Early Stage ◽  
Strain Curve ◽  
Orientation Dependence ◽  
Stress Strain Curve ◽  
Softening Effect ◽  
Solid Solution Softening

Solid solution softening and the orientation dependence of yield stress can be regarded as the two most important phenomena characterizing the low temperature plastic deformation of b.c.c. metals. Recently, the orientation dependence of solid solution softening was reported in electron irradiated pure iron in which self-interstitial atoms simulate the solid solution effect. Single crystals oriented for the hard (112) slip showed the largest softening effect and became the softest crystals after irradiation (Fig. 1). Also, the shape of the stress-strain curve for the irradiation-softened crystal suggests that the irradiation may have influenced the dislocation structure at an early stage of deformation. Specimens oriented for the soft (211) slip showed hardly any effect. In this study, the dislocation structure was investigated to determine the mechanism responsible for the softening effect and the orientation dependence.

scholarly journals Effect of annealing on dislocation structure parameters of ultrafine-grained copper: comparative study by acoustic and x-ray methods

2019 ◽  
Keyword(s):  
Low Temperature ◽  
Dislocation Density ◽  
Dislocation Structure ◽  
Subsequent Annealing ◽  
Peierls Stress ◽  
Acoustic Measurements ◽  
X Ray Diffraction ◽  
X Ray ◽  
Density Of Dislocations ◽  
Ultrafine Grained

The acoustic spectroscopy method and X-ray diffraction analysis were used to study the effect of severe plastic deformation (SPD) and subsequent annealing on the parameters of the dislocation structure of ultrafine-grained (UFG) FRTP (Fire Refining Tough Pitch) copper. To this end, the effect of SPD and subsequent annealing on the main parameters of the low-temperature Bordoni acoustic relaxation was studied in detail. Annealing was performed in the temperature range 90 – 430 C, including the primary crystallization temperature of highly deformed copper Tann  135 C. For all states of the samples, the estimates of the density of mobile dislocations m, which contribute to the low-temperature dynamic relaxation, are obtained. Annealing leads to the decrease in the dislocation density from m  1.7·1012 m-2 to m  1.5·1011 m-2. In addition to the dislocation density, an estimate of the 1st order Peierls’ stress 4 P  19 MPa 2.5·10 G    (G – shear modulus) was also obtained from the acoustic measurements. In parallel with the acoustic measurements, the parameters of the dislocation structure of the samples were studied by X-ray diffraction. The values of the lattice parameter, the values of microdeformation, the average size of the coherent scattering region (CSR), and also the average density of dislocations were obtained. It turned out that the X-ray density of dislocations is two orders of magnitude higher than the values obtained from acoustic measurements. At the same time, the data on the effect of annealing obtained by both methods are in qualitative agreement with each other; in particular, a decrease in the dislocation density of the same order of magnitude is observed.

The dislocation structure of a 10° [110] tilt boundary in silicon

1983 ◽  
Vol 41 ◽  
pp. 114-115
Author(s):  
B. Cunningham ◽  
D.G. Ast
Keyword(s):  
Dislocation Structure ◽  
Tilt Angle ◽  
Imaging Technique ◽  
Diamond Lattice ◽  
Tilt Boundary ◽  
Formation Mechanisms ◽  
Diffraction Contrast ◽  
Lattice Fringe ◽  
Tilt Boundaries ◽  
Chemically Vapor Deposited

There have Been a number of studies of low-angle, θ < 4°, [10] tilt boundaries in the diamond lattice. Dislocations with Burgers vectors a/2<110>, a/2<112>, a<111> and a<001> have been reported in melt-grown bicrystals of germanium, and dislocations with Burgers vectors a<001> and a/2<112> have been reported in hot-pressed bicrystals of silicon. Most of the dislocations were found to be dissociated, the dissociation widths being dependent on the tilt angle. Possible dissociation schemes and formation mechanisms for the a<001> and a<111> dislocations from the interaction of lattice dislocations have recently been given.The present study reports on the dislocation structure of a 10° [10] tilt boundary in chemically vapor deposited silicon. The dislocations in the boundary were spaced about 1-3nm apart, making them difficult to resolve by conventional diffraction contrast techniques. The dislocation structure was therefore studied by the lattice-fringe imaging technique.

Exsolution and inversion in pigeonite from the Whin Sill, Northern England

1978 ◽  
Vol 36 (1) ◽  
pp. 474-475
Author(s):  
P.P.K. Smith
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Homogeneous Nucleation ◽  
Silicate Mineral ◽  
Antiphase Boundaries ◽  
Two Phase ◽  
Primitive Form ◽  
The Core ◽  
Nucleation Mechanisms ◽  
And Inversion

Grains of pigeonite, a calcium-poor silicate mineral of the pyroxene group, from the Whin Sill dolerite have been ion-thinned and examined by TEM. The pigeonite is strongly zoned chemically from the composition Wo8En64FS28 in the core to Wo13En34FS53 at the rim. Two phase transformations have occurred during the cooling of this pigeonite:- exsolution of augite, a more calcic pyroxene, and inversion of the pigeonite from the high- temperature C face-centred form to the low-temperature primitive form, with the formation of antiphase boundaries (APB's). Different sequences of these exsolution and inversion reactions, together with different nucleation mechanisms of the augite, have created three distinct microstructures depending on the position in the grain.In the core of the grains small platelets of augite about 0.02μm thick have farmed parallel to the (001) plane (Fig. 1). These are thought to have exsolved by homogeneous nucleation. Subsequently the inversion of the pigeonite has led to the creation of APB's.

Mechanical Properties and Dislocation Structure of Single Crystal Cdte Deformed in Compression at 300°C

1976 ◽  
Vol 34 ◽  
pp. 592-593
Author(s):  
Ernest L. Hall ◽  
J. B. Vander Sande
Keyword(s):  
Mechanical Properties ◽  
Single Crystal ◽  
Dislocation Structure ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Strain Curve ◽  
Optical Devices ◽  
Semiconductor Compound ◽  
Wide Range ◽  
Sample Orientation

The present paper describes research on the mechanical properties and related dislocation structure of CdTe, a II-VI semiconductor compound with a wide range of uses in electrical and optical devices. At room temperature CdTe exhibits little plasticity and at the same time relatively low strength and hardness. The mechanical behavior of CdTe was examined at elevated temperatures with the goal of understanding plastic flow in this material and eventually improving the room temperature properties. Several samples of single crystal CdTe of identical size and crystallographic orientation were deformed in compression at 300°C to various levels of total strain. A resolved shear stress vs. compressive glide strain curve (Figure la) was derived from the results of the tests and the knowledge of the sample orientation.

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