Plastic flow instability: Chernov–Lüders bands and the Portevin—Le Chatelier effect

2017 ◽  
Vol 62 (3) ◽  
pp. 395-400 ◽  
Author(s):  
V. V. Gorbatenko ◽  
V. I. Danilov ◽  
L. B. Zuev
Keyword(s):  
Plastic Flow ◽  
Flow Instability ◽  
Chatelier Effect ◽  
Lüders Bands

Chernov–Lüders bands and the Portevin–Le Chatelier effect as plastic flow instabilities

2017 ◽  
Vol 2017 (4) ◽  
pp. 231-236 ◽  
Author(s):  
L. B. Zuev ◽  
V. V. Gorbatenko ◽  
V. I. Danilov
Keyword(s):  
Plastic Flow ◽  
Flow Instabilities ◽  
Chatelier Effect ◽  
Lüders Bands

Mesoscale plastic flow instability in a solid under high-rate deformation

2017 ◽  
Vol 20 (4) ◽  
pp. 417-424 ◽  
Author(s):  
T. A. Khantuleva ◽  
Yu. I. Meshcheryakov
Keyword(s):  
Plastic Flow ◽  
Flow Instability ◽  
High Rate ◽  
High Rate Deformation

scholarly journals Viscous Shear Banding in Cutting of Metals

2018 ◽  
Vol 140 (11) ◽  
Author(s):  
Dinakar Sagapuram ◽  
Koushik Viswanathan
Keyword(s):  
Plastic Flow ◽  
Flow Instability ◽  
Liquid Metals ◽  
Shear Banding ◽  
Shear Bands ◽  
Local Deformation ◽  
Flow Rule ◽  
Sliding Mechanism ◽  
Viscous Shear ◽  
Local Shear

Shear banding is a type of plastic flow instability with often adverse implications for cutting and deformation processing of metals. Here, we study the mechanics of plastic flow evolution within single shear bands in Ti- and Ni-based alloy systems. The local shear band displacement profiles are quantitatively mapped at high resolution using a special micromarker technique. The results show that shear bands, once nucleated, evolve by a universal viscous sliding mechanism that is independent of microstructural details. The evolution of local deformation around the band is accurately captured by a momentum diffusion equation based on a Bingham-type flow rule. The predicted band viscosity is very small, compared to those of liquid metals. A plausible explanation for this small viscosity and fluid-like behavior at the band, based on phonon drag, is presented.

Analysis of Plastic Flow Instability During Superplastic Deformation of the Zn-Al Eutectoid Alloy Modified with 2 wt.% Cu

2017 ◽  
Vol 26 (11) ◽  
pp. 5304-5311 ◽  
Author(s):  
Mitsuo Ramos-Azpeitia ◽  
E. Elizabeth Martínez-Flores ◽  
Jose Luis Hernandez-Rivera ◽  
Gabriel Torres-Villaseñor
Keyword(s):  
Plastic Flow ◽  
Superplastic Deformation ◽  
Flow Instability ◽  
Eutectoid Alloy

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 Автоволновое описание пластичности материалов с нестабильной фазовой структурой на макромасштабном уровне

2021 ◽  
Vol 91 (2) ◽  
pp. 267
Author(s):  
В.И. Данилов ◽  
Л.Б. Зуев ◽  
В.В. Горбатенко ◽  
Л.В. Данилова ◽  
Д.В. Орлова
Keyword(s):  
Plastic Deformation ◽  
Digital Image Correlation ◽  
Phase Transformations ◽  
Plastic Flow ◽  
Experimental Analysis ◽  
Titanium Nickelide ◽  
Image Correlation ◽  
Mechanisms Of Formation ◽  
Deformation Processes ◽  
Lüders Bands

The regularities of plastic flow in materials with deformation-induced phase transformations on the example of titanium nickelide and TRIP steel are studied. For experimental analysis of plastic deformation processes, the method of digital image correlation has been used, which allows us to quantitatively describe the behavior of plasticity fronts associated with the course of phase transformations in the materials under study. The mechanisms of formation of Lüders bands and Portevin-Le Chatelier bands at different stages of plastic flow are considered.

Viscous Shear Banding in Cutting of Metals

2018 ◽  
Author(s):  
Dinakar Sagapuram ◽  
Koushik Viswanathan
Keyword(s):  
Plastic Flow ◽  
Flow Instability ◽  
Liquid Metals ◽  
Shear Banding ◽  
Shear Bands ◽  
Local Deformation ◽  
Bingham Flow ◽  
Sliding Mechanism ◽  
Viscous Shear ◽  
Local Shear

Shear banding is a type of plastic flow instability with often adverse implications for cutting and deformation processing of metals. Here, we study the mechanics of plastic flow evolution within single shear bands in two different (Ti and Ni-based) alloy systems. The local shear band displacement profiles are quantitatively mapped at high resolution using a special micro-marker technique. The results show that shear bands, once nucleated, evolve by a universal viscous sliding mechanism that is independent of microstructural details. The evolution of local deformation around the band is accurately captured using a simple momentum diffusion model by assuming Bingham flow rheology for the band material. The predicted band viscosity is very small, comparable to those of liquid metals. A plausible explanation for this small viscosity and fluid-like behavior at the band, based on phonon drag, is presented.

scholarly journals MATHEMATICAL MODELING OF THE INFLUENCE PARAMETERS DURING FORMATION AND PROPAGATION OF THE LÜDERS BANDS

2020 ◽  
pp. 595
Author(s):  
Tin Brlić ◽  
Stoja Rešković ◽  
Zoran Jurković ◽  
Gordan Janeš
Keyword(s):  
Mathematical Models ◽  
Plastic Flow ◽  
Local Stress ◽  
Image Correlation ◽  
Maximum Temperature ◽  
Microalloyed Steels ◽  
Band Formation ◽  
The Difference ◽  
Lüders Band ◽  
Lüders Bands

In this study, an analysis of the influence parameters measured by the static tensile test, thermography and digital image correlation was performed during formation and propagation of the Lüders bands. A new approach to the prediction of stresses, maximum temperature changes and strains during the Lüders band formation and propagation is proposed in this paper. Application of the obtained mathematical models of influence parameters gives a clear insight into the behavior of niobium microalloyed steel at the beginning of the plastic flow, which can improve product quality and reduce costs during the forming of microalloyed steels with the appearance of the Lüders bands. The obtained models of influential parameters during formation and propagation of the Lüders bands have been developed by the regression analysis method. The proposed mathematical models showed low deviations of calculated results ranging from 1.34% to 12.37%.The local stress amounts, important in the forming of microalloyed steels since indicating surface roughness and plastic flow possibilities during the Lüders band propagation, are obtained by the mathematical model. It was found that stress amounts increase during the Lüders band propagation in the area behind the Lüders band front. The difference in stress amount between the start of the Lüders band propagation and advanced Lüders band propagation is 25.53 MPa.

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