Micromechanics of Hysteresis Loops of Fatigue in a Single Crystal

1999 ◽  
Vol 67 (2) ◽  
pp. 338-343 ◽  
Author(s):  
T. H. Lin ◽  
K. K. F. Wong ◽  
N. J. Teng
Keyword(s):  
Plastic Strain ◽  
Shear Band ◽  
Single Crystal ◽  
Single Crystals ◽  
Slip Band ◽  
Creep Deformation ◽  
Bauschinger Effect ◽  
Plane Deformation ◽  
Hysteresis Loops ◽  
Turbine Engines

Grain boundaries are susceptible to cause boundary corrosion, cracking, and creep deformation. Single crystals are presently used in turbine engines. A micromechanic analysis is shown to explain the occurrence of highly localized plastic strain in the slip band known as the shear band in metals under a monotonic loading. Based on the prior analyses of fatigue bands in polycrystals, a micromechanic analysis of a single crystal under plane deformation is developed. The Bauschinger effect and hysteresis loops of these single crystals were calculated and shown. The calculated results agree generally with experimental observations. [S0021-8936(00)02202-9]

scholarly journals Ferroelectricity and Phase Transitions in Pyridinium Periodate Single Crystal

2000 ◽  
Vol 55 (11-12) ◽  
pp. 891-894 ◽  
Author(s):  
Z. Czapla ◽  
S. Dacko ◽  
B. Kosturek
Keyword(s):  
Phase Transitions ◽  
Physical Properties ◽  
Single Crystal ◽  
Single Crystals ◽  
Phase Ii ◽  
Ferroelectric Phase ◽  
Hysteresis Loops ◽  
Electric Permittivity ◽  
Phase Ii And Iii ◽  
Three Phases

Abstract Single crystals of pyridinium periodate were grown, and their physical properties were studied. Anomalies of the electric permittivity and birefringence were observed at TC1 = 321 K and TC2 = 211 K. These observations gave evidences for the existence of three phases denoted as I, II, and III. Hysteresis loops were observed both in phase II and III. Pyroelectric measurements showed two anomalies at TC1 and TC2 . The anomaly at TC1 is related to the transition between a para-and ferroelectric phase, and the anomaly at T cl to the transition between two ferroelectric phases.

scholarly journals Inverse Slip Accompanying Twinning and Detwinning during Cyclic Loading of Magnesium Single Crystal

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Qin Yu ◽  
Jian Wang ◽  
Yanyao Jiang
Keyword(s):  
Quantitative Analysis ◽  
Cyclic Loading ◽  
Plastic Strain ◽  
Single Crystal ◽  
Single Crystals ◽  
Work Hardening ◽  
Two Stages ◽  
First Time ◽  
High Work

In situ, observation of twinning and detwinning in magnesium single crystals during tension-compression cyclic loading was made using optical microscopy. A quantitative analysis of plastic strain indicates that twinning and detwinning experience two stages, low and high work hardening de-twinning, and pure re-twinning and fresh twinning combined with retwinning. Slip is always activated. For the first time, inverse slip accompanying with pure retwinning and high work hardening detwinning was experimentally identified, which provides insights in better understanding of the activity of twining, detwinning, and slips.

Anisotropic Magnetization in Single Crystal YBa2Cu3O7

1987 ◽  
Vol 01 (02) ◽  
pp. 401-408 ◽  
Author(s):  
R.N. Shelton ◽  
R.W. McCallum ◽  
M.A. Damento ◽  
K.A. Gschneidner
Keyword(s):  
Magnetic Properties ◽  
Transition Temperature ◽  
Critical Temperature ◽  
Critical Current Density ◽  
Single Crystal ◽  
Single Crystals ◽  
Current Density ◽  
Applied Field ◽  
Hysteresis Loops ◽  
Anisotropic Magnetization

Magnetization measurements on single crystals of YBa2Cu3O7 are used to study the anisotropy of the critical current density and magnetic properties of this superconducting oxide with a transition temperature of 88 K. Anisotropy of the magnetization versus applied field hysteresis loops is pronounced, with the effect increasing as the temperature approaches the superconducting critical temperature.

High-accuracy polarimetric studies on lead germinate single crystals

2021 ◽  
Vol 54 (6) ◽  
Author(s):  
Mykola Shopa ◽  
Nazar Ftomyn ◽  
Yaroslav Shopa
Keyword(s):  
Electric Field ◽  
Single Crystal ◽  
Single Crystals ◽  
Hysteresis Loops ◽  
High Accuracy ◽  
Tensor Component ◽  
Lead Germanate ◽  
Measurement Results ◽  
Ferroelectric Single Crystal

A high-accuracy polarimetric technique has been used for the characterization of a lead germanate ferroelectric single crystal. The measurement results of the linear and circular birefringence in the [010] direction at a wavelength of 633 nm under the influence of an electric field are presented. Gyration–electric field hysteresis loops at alternative crystal positions in the polarization system have been used to determine the ellipticity of the eigenwaves. A temperature dependence of the gyration tensor component g 11 in the temperature range of 300–450 K was found.

Characterization of Epitaxial Bi-Layer-Structured Bi5Ti3FeO15 (m = 4) and Bi4Ti3O12-Bi5Ti3FeO15 (m = 3-4) Natural-Superlattice-Structured Multiferroic Thin Films Prepared by Pulsed Laser deposition

2007 ◽  
Vol 1034 ◽  
Author(s):  
Seiji Nakashima ◽  
Yoshitaka Nakamura ◽  
Masanori Okuyama
Keyword(s):  
Thin Films ◽  
Single Crystal ◽  
Pulsed Laser Deposition ◽  
Single Crystals ◽  
Ferroelectric Properties ◽  
Pulsed Laser ◽  
Hysteresis Loops ◽  
Laser Deposition ◽  
Natural Superlattice ◽  
La Doped

AbstractBi-layer-structured mutiferroic Bi5Ti3FeO15 (BTFO15) (m = 4) and natural-superlattice-structured Bi4Ti3O12- Bi5Ti3FeO15 (BIT-BTFO15) (m = 3-4) thin films have been prepared on (001) and (110) oriented SrTiO3 (STO) single crystal substrates by using pulsed laser deposition. X-ray diffraction patterns of these thin films on (00l) STO single crystals shows the obtained thin films were (00l)-oriented layer-perovskite single phase, and BIT-BTFO15 (m = 3-4) natural-superlattice-structure has also obtained. On (110) STO single crystal, layer perovskite (11l) oriented thin films have been also obtained. For characterizing ferroelectric properties, these thin films have been prepared on (001) and (110) oriented La-doped (3.73 wt%) STO single crystal substrates. From ferroelectric D-E hysteresis loops measurements, BTFO15 (m = 4) and BIT-BTFO (m = 3-4) thin films on (110) La-doped STO single crystals shows good ferroelectric hysteresis loops and their double remanent polarizations (2Pr) were 47 μC/cm2 and 44 μC/cm2, respectively. However, these thin films on (001) La-doped STO single crystals do not show ferroelectric characteristics.

Change in Stress Axis with Creep Deformation in Ni-20mass%Cr Single Crystal with Orientation of [011]

2006 ◽  
Vol 15-17 ◽  
pp. 870-875 ◽  
Author(s):  
Masaomi Mitsutake ◽  
Yoshihiro Terada ◽  
Takashi Matsuo
Keyword(s):  
Creep Rate ◽  
Single Crystal ◽  
Single Crystals ◽  
Slip Plane ◽  
Creep Deformation ◽  
Stage I ◽  
Stage Ii ◽  
Stress Axis ◽  
Transient Stage ◽  
Primary Slip Plane

The features of the creep deformation of γ-single phase single crystals with the composition of Ni-20mass%Cr are characterized by the extended transient stage, which consists of Stage I and Stage II. In the Stage I, the creep rate just after loading remains unchanged, while the creep rate decreases continuously in Stage II. In the single crystals except for the single crystals with the stress axis of [001] and [1, – 11], the predominant creep deformation using the primary slip plane continues. By this deformation, the cross section of specimen turns to elliptical in shape. However, in the single crystals with the angle between stress axis and primary slip plane (111) is more than 45°, the deformation using the primary slip plane does not continue, as a result, the duration of Stage II turn to shorter one. The single crystal with the stress axis of [011] has the largest angle of 55°. In this study, the deformation manner during transient stage of single crystal with the stress axis of [011] orientation is investigated from the two viewpoints. The first one is to clarify the change in deformation manner with decreasing the stress. As a result, with decreasing the stress, the Stage I become clear and strain during Stage I and Stage II become small, furthermore, the decreasing ratio of creep rate with definite strain becomes larger. While, the second viewpoint is to investigate the change in crystallographic orientation of the [011] single crystals with creep deformation using the inverse pole figure obtained by the EBSD method. As a result, at the stress of 29.4 MPa, the spot of stress axis turns from the [011]-[1, – 11] line to the <1, – 01> direction. While, at the stress of 19.6 MPa, the stress axis moves for the [1, – 11] pole along the [011]-[1, – 11] line from the [011] pole. And, it is noteworthy that the spot widely spread from the [011] pole during transient stage. This indicates the large distortion in the primary slip plane and the evidence of heterogeneous deformation.

The observation of defects on (100) CdTe surfaces by chemical etching

1992 ◽  
Vol 50 (2) ◽  
pp. 1424-1425
Author(s):  
M.E. Lee
Keyword(s):  
Single Crystal ◽  
Grain Boundaries ◽  
Single Crystals ◽  
Chemical Etching ◽  
Crystalline Perfection ◽  
Crystalline Defects ◽  
High Incidence ◽  
Crystallographic Defects ◽  
Cdznte Substrates ◽  
Device Technology

The crystalline perfection of bulk CdTe substrates plays an important role in their use in infrared device technology. The application of chemical etchants to determine crystal polarity or the density and distribution of crystallographic defects in (100) CdTe is not well understood. The lack of data on (100) CdTe surfaces is a result of the apparent difficulty in growing (100) CdTe single crystal substrates which is caused by a high incidence of twinning. Many etchants have been reported to predict polarity on one or both (111) CdTe planes but are considered to be unsuitable as defect etchants. An etchant reported recently has been considered to be a true defect etchant for CdTe, MCT and CdZnTe substrates. This etchant has been reported to reveal crystalline defects such as dislocations, grain boundaries and inclusions in (110) and (111) CdTe. In this study the effect of this new etchant on (100) CdTe surfaces is investigated.The single crystals used in this study were (100) CdTe as-cut slices (1mm thickness) from Bridgman-grown ingots.

Mounting an individual submicrometer sized single crystal

1996 ◽  
Vol 211 (6) ◽  
Author(s):  
R. B. Neder ◽  
M. Burghammer ◽  
Th. Grasl ◽  
H. Schulz
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Single Crystal ◽  
Single Crystals ◽  
High Vacuum ◽  
Nanometer Resolution ◽  
Micro Manipulator ◽  
Scanning Electron

AbstractWe developed a new micro manipulator for mounting individual sub-micrometer sized single crystals within a scanning electron microscope. The translations are realized via a commercially available piezomicroscope, adapted for high vacuum usage and realize nanometer resolution. With this novel instrument it is routinely possible to mount individual single crystals with sizes down to 0.1

Study of potential oscillations during reaction of an aluminium single crystal with an aqueous KOH solution

1990 ◽  
Vol 55 (2) ◽  
pp. 345-353 ◽  
Author(s):  
Ivan Halaša ◽  
Milica Miadoková
Keyword(s):  
Aqueous Solutions ◽  
Single Crystal ◽  
Single Crystals ◽  
Periodic Potential ◽  
Optimum Conditions ◽  
Potential Oscillations ◽  
Dilute Aqueous Solutions ◽  
Experimental Findings ◽  
Kinetics Of

The authors investigated periodic potential changes measured on oriented sections of Al single crystals during spontaneous dissolution in dilute aqueous solutions of KOH, with the aim to find optimum conditions for the formation of potential oscillations. It was found that this phenomenon is related with the kinetics of the reaction investigated, whose rate also changed periodically. The mechanism of the oscillations is discussed in view of the experimental findings.

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