Relaxation Mode of Macroscopic Plastic Deformation in Metals

2021 ◽  
Vol 63 (9) ◽  
pp. 1545-1547
Author(s):  
Yu. A. Khon ◽  
L. B. Zuev
Keyword(s):  
Plastic Deformation ◽  
Relaxation Mode ◽  
Macroscopic Plastic Deformation

scholarly journals Relaxation mode of macroscopic plastic deformation in metals

2020 ◽  
pp. 86-88
Author(s):  
Yu.A. Khon ◽  
◽  
L.B. Zuev ◽  
Keyword(s):  
Plastic Deformation ◽  
Parabolic Equation ◽  
Nonlinear Systems ◽  
Unstable Mode ◽  
System Of Nonlinear Equations ◽  
Relaxation Mode ◽  
Deformable Solid ◽  
Spatial And Temporal Scales ◽  
Nonlinear Parabolic ◽  
Macroscopic Plastic Deformation

The relaxation of elastic energy during macroscopic plastic deformation in a strict formulation is determined by the solutions of the system of nonlinear equations of mechanics of a deformable solid. Using the methods of the theory of nonlinear systems, a nonlinear parabolic equation is obtained for the amplitude of an unstable mode, which describes plastic deformation at large spatial and temporal scales.

Discountinuity of Plastic Flow Controlled by Magnetic Field in NaCl:Eu Crystals

2006 ◽  
Vol 115 ◽  
pp. 183-192 ◽  
Author(s):  
L. Dunin-Barkovskii ◽  
R.B. Morgunov ◽  
Y. Tanimoto
Keyword(s):  
Magnetic Field ◽  
Plastic Deformation ◽  
Plastic Flow ◽  
Constant Magnetic Field ◽  
Shear Bands ◽  
Internal Stresses ◽  
Deformation Jump ◽  
Chatelier Effect ◽  
Reference Specimens ◽  
Macroscopic Plastic Deformation

An influence of a constant magnetic field (MF) with induction up to 15 T upon macroscopic plastic deformation of diamagnetic NaCl single crystals containing paramagnetic Eu impurity was observed. Effects of MF on instability of plastic flow (on the Portevin-Le Chatelier effect) in quenched NaCl:Eu crystals were found. The MF results in a decrease of the yield stress, a decrease of the probability of the instability appearance, and a decrease of the averaged magnitude of the deformation jumps, as well as in a chaotization of the distribution of the deformation jump magnitudes. The latter can be explained by partial plastic relaxation of internal stresses under MF that was confirmed by dislocations displacement induced by internal stresses in MF. The averaged amount of shear bands observed on the surface of the investigated crystals deformed under MF is half of that in reference specimens.

The Nanometer Scaled Defects Induces with the Dislocation Motion in II-VI Insulated Semiconductors

2011 ◽  
Vol 276 ◽  
pp. 195-202
Author(s):  
V.N. Babentsov ◽  
V.A. Boyko ◽  
A.F. Kolomys ◽  
G.A. Shepelski ◽  
V.V. Strelchuk ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Low Temperature ◽  
Crystallographic Orientation ◽  
Chemical Etching ◽  
Dislocation Motion ◽  
Low Temperature Photoluminescence ◽  
Macroscopic Plastic Deformation

Dislocation-related defects induced by dislocation motion in p-CdTe were studied. Generation of “fresh” dislocations from the indented point of the CdTe (100), (110), and (111) surfaces at room temperatures was visualized by the chemical etching and low temperature photoluminescence in a mapping regime. The crystallographic orientation of the dislocation rosettes of macroscopic plastic deformation lines was analyzed on the (100), (110), and (111) surfaces.

Sem Examinations of Glass Knives

1970 ◽  
Vol 28 ◽  
pp. 282-283
Author(s):  
J. Temple Black
Keyword(s):  
Plastic Deformation ◽  
Tensile Loading ◽  
Resultant Force ◽  
Stress Concentrations ◽  
Edge Chipping ◽  
Surface Flaws ◽  
Edge Defects ◽  
Microscopic Surface

There are two types of edge defects common to glass knives as typically prepared for microtomy purposes: 1) striations and 2) edge chipping. The former is a function of the free breaking process while edge chipping results from usage or bumping of the edge. Because glass has no well defined planes in its structure, it should be highly resistant to plastic deformation of any sort, including tensile loading. In practice, prevention of microscopic surface flaws is impossible. The surface flaws produce stress concentrations so that tensile strengths in glass are typically 10-20 kpsi and vary only slightly with composition. If glass can be kept in compression, wherein failure is literally unknown (1), it will remain intact for long periods of time. Forces acting on the tool in microtomy produce a resultant force that acts to keep the edge in compression.

Stereo Electron Microscopy Applied to High Resolution Freeze-Etch Replicas

1970 ◽  
Vol 28 ◽  
pp. 306-307
Author(s):  
L. Andrew Staehelin
Keyword(s):  
Electron Microscopy ◽  
Plastic Deformation ◽  
High Resolution ◽  
Smooth Surfaces ◽  
Small Particles ◽  
Membrane Surfaces ◽  
Wide Acceptance ◽  
New Information ◽  
Number Of Particles ◽  
Small Holes

Freeze-etched membranes usually appear as relatively smooth surfaces covered with numerous small particles and a few small holes (Fig. 1). In 1966 Branton (1“) suggested that these surfaces represent split inner mem¬brane faces and not true external membrane surfaces. His theory has now gained wide acceptance partly due to new information obtained from double replicas of freeze-cleaved specimens (2,3) and from freeze-etch experi¬ments with surface labeled membranes (4). While theses studies have fur¬ther substantiated the basic idea of membrane splitting and have shown clearly which membrane faces are complementary to each other, they have left the question open, why the replicated membrane faces usually exhibit con¬siderably fewer holes than particles. According to Branton's theory the number of holes should on the average equal the number of particles. The absence of these holes can be explained in either of two ways: a) it is possible that no holes are formed during the cleaving process e.g. due to plastic deformation (5); b) holes may arise during the cleaving process but remain undetected because of inadequate replication and microscope techniques.

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