Microscopic and macroscopic plastic deformation as a criterion of the limiting state of a material during fracture

1984 ◽  
Vol 16 (4) ◽  
pp. 473-479 ◽  
Author(s):  
G. V. Klevtsov ◽  
L. R. Botvina
Keyword(s):  
Plastic Deformation ◽  
Limiting State ◽  
Macroscopic Plastic Deformation

scholarly journals Effect of vibration treatment on increasing the durability of tillage equipment working bodies

2021 ◽  
Vol 2 (1 (110)) ◽  
pp. 104-108
Author(s):  
Anatolii Dudnikov ◽  
Olena Ivankova ◽  
Oleksandr Gorbenko ◽  
Anton Kelemesh
Keyword(s):  
Plastic Deformation ◽  
Hardened Layer ◽  
Wear Depth ◽  
Machined Surface ◽  
Limiting State ◽  
Vibration Treatment ◽  
Fine Grained ◽  
Residual Thickness ◽  
Compliance With The Law ◽  
Working Bodies

This paper reports a study into the durability of tillage equipment working bodies. It has been established that the quality of surface layers during plastic deformation depends on a series of factors. These factors include the degree of hardening, the thickness of the hardened layer, the size and nature of the distribution of residual stresses. The study has shown that the technology to restore working bodies that involves vibration oscillations provides for higher durability. Investigation of deformed samples demonstrates that when exposed to vibration treatment, the microstructure is more fine-grained and even; the hardness of the treated surface of a ploughshare blade increases by 22‒35 %. This contributes to hardening the machined surface. It has been established that the tillage equipment working body wear is a random process, which is predetermined by changes in the structural dimensions and shape of cutting elements. An analysis of the wear distribution density of cutting elements has revealed its compliance with the law of normal distribution. It should be noted that the most influential geometric parameter of a working body affecting the part’s resource is the wear depth. This parameter determines the residual thickness of the ploughshare wall. Data from surface-layer studies at hardening make it possible to note a decrease in the limiting state of the examined parameters. In particular, the wear of a ploughshare tip was 17 % less than the limiting state. The study of durability has shown that the amount of tillage equipment working body wear is 1.28 times less when using vibrational plastic deformation. Accordingly, when restoring ploughshares, in order to increase the working bodies’ resource, it is more expedient to use a method that implies the welding of tires made from steel 45 involving sormite surfacing and vibration treatment

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.

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.

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