Effects of Plastic Deformation on Charge Transport in Mercuric Iodide Radiation Detectors

1991 ◽  
Vol 226 ◽  
Author(s):  
J. Marschall ◽  
F. Milstein ◽  
G. Georgeson ◽  
V. Gerrish
Keyword(s):  
Plastic Deformation ◽  
Plastic Strain ◽  
Charge Transport ◽  
Electronic Properties ◽  
Dark Current ◽  
Radiation Detector ◽  
Radiation Detectors ◽  
Mercuric Iodide ◽  
Plastic Damage ◽  
Creep Loading

AbstractThe effects of bulk plastic deformation of mercuric iodide (HgI2), upon electronic properties which are relevant to the performance of HgI2 as a radiation detector, were examined experimentally. Hole lifetimes, as well as hole and electron mobilities, were measured at various stages of sample deformation. Hole lifetimes decreased by a factor of 2 under strains of several percent; carrier mobilities did not change significantly, except during creep loading where electron and hole mobilities decreased by about 65% and 25%, respectively. Additionally, dark current measurements were made on specimens with varying degrees of accumulated plastic strain; dark current values did not strongly reflect the extent of plastic damage in deformed specimens.

Plastic Deformation in Microtomed Sections

1971 ◽  
Vol 29 ◽  
pp. 458-459
Author(s):  
J. Temple Black
Keyword(s):  
Plastic Deformation ◽  
Plastic Strain ◽  
Applied Stress ◽  
Elastic Strain ◽  
High Strain ◽  
Tool Material ◽  
Cutting Edge ◽  
Material Structure ◽  
Geometrical Constraints

The output of the ultramicrotomy process with its high strain levels is dependent upon the input, ie., the nature of the material being machined. Apart from the geometrical constraints offered by the rake and clearance faces of the tool, each material is free to deform in whatever manner necessary to satisfy its material structure and interatomic constraints. Noncrystalline materials appear to survive the process undamaged when observed in the TEM. As has been demonstrated however microtomed plastics do in fact suffer damage to the top and bottom surfaces of the section regardless of the sharpness of the cutting edge or the tool material. The energy required to seperate the section from the block is not easily propogated through the section because the material is amorphous in nature and has no preferred crystalline planes upon which defects can move large distances to relieve the applied stress. Thus, the cutting stresses are supported elastically in the internal or bulk and plastically in the surfaces. The elastic strain can be recovered while the plastic strain is not reversible and will remain in the section after cutting is complete.

Charge Transport and Space-Charge Formation in Cd1−xZnxTe1−ySey Radiation Detectors

2021 ◽  
Vol 15 (5) ◽  
Author(s):  
J. Pipek ◽  
M. Betušiak ◽  
E. Belas ◽  
R. Grill ◽  
P. Praus ◽  
...  
Keyword(s):  
Space Charge ◽  
Charge Transport ◽  
Radiation Detectors ◽  
Charge Formation

Fused donor–acceptor π-conjugated diazatruxenones: synthesis and electronic properties

2018 ◽  
Vol 5 (11) ◽  
pp. 1748-1755 ◽  
Author(s):  
Angela Benito-Hernández ◽  
Mardia T. El-Sayed ◽  
Juan T. López Navarrete ◽  
M. Carmen Ruiz Delgado ◽  
Berta Gómez-Lor
Keyword(s):  
Charge Transport ◽  
Electronic Properties ◽  
Acceptor Molecule ◽  
Promising Candidate ◽  
Donor Acceptor

A promising candidate for ambipolar charge transport: a disk-like platform, diazatruxenone, as a novel, compact and planar donor–acceptor molecule.

Growth direction dependent separate-channel charge transport in organic weak charge-transfer co-crystal of anthracene-DTTCNQ

2022 ◽  
Author(s):  
Hui Jiang ◽  
Jun Ye ◽  
Peng Hu ◽  
Shengli Zhu ◽  
Yanqin Liang ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Charge Transport ◽  
Electronic Properties ◽  
Single Crystals ◽  
Organic Semiconductors ◽  
Crystal Engineering ◽  
Molecular Crystal ◽  
Growth Direction ◽  
Weak Charge ◽  
Separate Channel

Co-crystallization is an efficient way of molecular crystal engineering to tune the electronic properties of organic semiconductors. In this work, we synthesized anthracene-4,8-bis(dicyanomethylene)4,8-dihydrobenzo[1,2-b:4,5-b’]-dithiophene (DTTCNQ) single crystals as a template to...

scholarly journals Elasto-plastic analysis of the contact region between a rigid ellipsoid and a semi-flat surface

2018 ◽  
Vol 10 (9) ◽  
pp. 168781401879739 ◽  
Author(s):  
Pengyang Li ◽  
Lingxia Zhou ◽  
Fangyuan Cui ◽  
Quandai Wang ◽  
Meiling Guo ◽  
...  
Keyword(s):  
Residual Stress ◽  
Plastic Deformation ◽  
Plastic Strain ◽  
Contact Pressure ◽  
Contact Region ◽  
Three Dimensional ◽  
Von Mises Stress ◽  
Effective Plastic Strain ◽  
Normal Forces ◽  
Von Mises

When the load acting on a mechanical structure is greater than the yield strength of the material, the contact surface will undergo plastic deformation. Cumulative plastic deformation has an important influence on the lifespan of mechanical parts. This article presents a three-dimensional semi-analytical model based on the conjugate gradient method and fast Fourier transform algorithm, with the aim of studying the characteristic parameters of the contact region between a rigid ellipsoid and elasto-plastic half-space. Moreover, normal forces and tangential traction were considered, as well as the contact pressure resulting from various sliding speeds and friction coefficients. The contact pressure, effective plastic strain, von Mises stress, and residual stress were measured and shown to increase with increasing sliding velocity. Finally, when the friction coefficient, contact pressure, and effective plastic strain are increased, the von Mises stress is also shown to increase, whereas the residual stress decreases.

Life Remaining Prognostics for Structural Components

2007 ◽  
Author(s):  
Curtis A. Rideout ◽  
Scott J. Ritchie
Keyword(s):  
Plastic Deformation ◽  
Plastic Strain ◽  
Fatigue Testing ◽  
Structural Components ◽  
Aerospace Materials ◽  
Safe Operation ◽  
Operational Conditions ◽  
Aerospace Material ◽  
S Parameter ◽  
Structural Parts

Retirement criteria for many structural components and particularly landing gear structural parts, are generally based on analytical fatigue methods because the current means of detecting actual component damage cannot detect sufficiently small levels of damage such that safe operation for a useful interval can be confidently determined; limiting the capability to apply damage tolerance methods. The testing completed in these projects demonstrated that Induced Positron Analysis (IPA) technologies are sensitive to the tensile plastic strain damage induced in aerospace material specimens and components. The IPA process has shown that IPA methods can reliably detect and quantify plastic strain and plastic deformation under simulated and operational conditions. A preliminary functional relationship between total strain and the normalized IPA S parameter has been developed for several aerospace materials. The fatigue testing has demonstrated the IPA technologies have potential to detect fatigue damage induced in specimens and operational components when the loads are large enough to cause plastic deformation.

The Effect of Plastic Deformation on the Thermoelastic Constant and the Potential to Evaluate Residual Stress

2011 ◽  
Vol 70 ◽  
pp. 458-463 ◽  
Author(s):  
A. F. Robinson ◽  
Janice M. Dulieu-Barton ◽  
S. Quinn ◽  
R. L. Burguete
Keyword(s):  
Residual Stress ◽  
Plastic Deformation ◽  
Plastic Strain ◽  
Strain Hardening ◽  
Thermoelastic Stress ◽  
Paint Coating ◽  
Full Field ◽  
Thermoelastic Constant ◽  
Thermoelastic Response ◽  
Measured Change

In some metals it has been shown that the introduction of plastic deformation or strain modifies the thermoelastic constant, K. If it was possible to define the magnitude of the change in thermoelastic constant over a range of plastic strain, then the plastic strain that a material has experienced could be established based on a measured change in the thermoelastic constant. This variation of the thermoelastic constant and the ability to estimate the plastic strain that has been experienced, has potential to form the basis of a novel non-destructive, non-contact, full-field technique for residual stress assessment using thermoelastic stress analysis (TSA). Recent research has suggested that the change in thermoelastic constant is related to the material dislocation that occurs during strain hardening, and thus the change in K for a material that does not strain harden would be significantly less than for a material that does. In the work described in this paper, the change in thermoelastic constant for three materials (316L stainless steel, AA2024 and AA7085) with different strain hardening characteristics is investigated. As the change in thermoelastic response due to plastic strain is small, and metallic specimens require a paint coating for TSA, the effects of the paint coating and other test factors on the thermoelastic response have been considered.

scholarly journals Studying Deformation Behaviors in Austenitic Stainless Steels within a Temperature Range of 143 K < T < 420 K

2021 ◽  
pp. 22-30
Author(s):  
S. A Barannikova ◽  
A. M Nikonova ◽  
S. V Kolosov
Keyword(s):  
Plastic Deformation ◽  
Plastic Strain ◽  
Strain Localization ◽  
Work Hardening ◽  
Deformation Localization ◽  
Linear Hardening ◽  
Jerky Flow ◽  
Temperature Range ◽  
Α Phase ◽  
Flow Stage

This work deals with studying staging and macroscopic strain localization in austenitic stainless steel 12Kh18N9T within a temperature range of 143 K < T < 420 K. The visualization and evolution of macroscopic localized plastic deformation bands at different stages of work hardening were carried out by the method of the double-exposure speckle photography (DESP), which allows registering displacement fields with a high accuracy by tracing changes on the surface of the material under study and then comparing the specklograms recorded during uniaxial tension. The shape of the tensile curves σ(ε) undergoes a significant change with a decreasing temperature due to the γ-α'-phase transformation induced by plastic deformation. The processing of the deformation curves of the steel samples made it possible to distinguish the following stages of strain hardening, i.e. the stage of linear hardening and jerky flow stage. A comparative analysis of the design diagrams (with the introduction of additional parameters of the Ludwigson equation) and experimental diagrams of tension of steel 12Kh18N9T for different temperatures is carried out. The analysis of local strains distributions showed that at the stage of linear work hardening, a mobile system of plastic strain localization centers is observed. The temperature dependence of the parameters of plastic deformation localization at the stages of linear work hardening has been established. Unlike the linear hardening, the jerky flow possesses the propagation of single plastic strain fronts that occur one after another through the sample due to the γ-α' phase transition and the Portevin-Le Chatelier effect. It was found that at the jerky flow stage, which is the final stage before the destruction of the sample, the centers of deformation localization do not merge, leading to the neck formation.

scholarly journals Stored Energy of Plastic Deformation in Tube Bending Processes

2013 ◽  
Vol 18 (1) ◽  
pp. 235-248 ◽  
Author(s):  
Z. Śloderbach ◽  
J. Pająk
Keyword(s):  
Plastic Deformation ◽  
Service Life ◽  
Plastic Strain ◽  
Analytic Method ◽  
Stored Energy ◽  
Tube Bending ◽  
Cold Bending ◽  
Tension And Compression

The paper presents an aproximate analytic method for determination of the stored energy of plastic deformation during cold bending of metal tubes at bending machines. Calculations were performed for outer points of the tube layers subjected to tension and compression (the points of maximum strains). The percentage of stored energy related to the plastic strain work was determined and the results were presented in graphs. The influence and importance of the stored energy of plastic deformation on the service life of pipeline bends are discussed.

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