scholarly journals Adiabatic shear bands formation in polycrystalline aluminium

2021 ◽  
Vol 1121 (1) ◽  
pp. 012007
Author(s):  
I Mania ◽  
H Paul ◽  
R Chulist ◽  
P Petrzak
Keyword(s):  
Shear Bands ◽  
Adiabatic Shear ◽  
Adiabatic Shear Bands

The Effect of Secondary Metalworking Processes on Susceptibility of Aircraft to Catastrophic Failures and Prevention Methods

2013 ◽  
Vol 58 (4) ◽  
pp. 1207-1212
Author(s):  
E.S. Dzidowski
Keyword(s):  
Dynamic Recovery ◽  
Fatigue Cracks ◽  
Shear Bands ◽  
Adiabatic Shear ◽  
Deformation Mechanisms ◽  
Processing Maps ◽  
Adiabatic Shear Bands ◽  
Flow Localization ◽  
Catastrophic Failures ◽  
Prevention Methods

Abstract The causes of plane crashes, stemming from the subcritical growth of fatigue cracks, are examined. It is found that the crashes occurred mainly because of the negligence of the defects arising in the course of secondary metalworking processes. It is shown that it is possible to prevent such damage, i.e. voids, wedge cracks, grain boundary cracks, adiabatic shear bands and flow localization, through the use of processing maps indicating the ranges in which the above defects arise and the ranges in which safe deformation mechanisms, such as deformation in dynamic recrystallization conditions, superplasticity, globularization and dynamic recovery, occur. Thanks to the use of such maps the processes can be optimized by selecting proper deformation rates and forming temperatures.

Formation of adiabatic shear bands and instability of plastic flow in Zr and Zr-Nb alloys in spherical stress waves

1999 ◽  
Vol 42 (1) ◽  
pp. 61-71 ◽  
Author(s):  
A.V Dobromyslov ◽  
N.I Taluts ◽  
N.V Kazantseva ◽  
E.A Kozlov
Keyword(s):  
Plastic Flow ◽  
Shear Bands ◽  
Stress Waves ◽  
Adiabatic Shear ◽  
Adiabatic Shear Bands

A microstructural investigation of adiabatic shear bands in an interstitial free steel

2007 ◽  
Vol 457 (1-2) ◽  
pp. 205-218 ◽  
Author(s):  
J.F.C. Lins ◽  
H.R.Z. Sandim ◽  
H.-J. Kestenbach ◽  
D. Raabe ◽  
K.S. Vecchio
Keyword(s):  
Shear Bands ◽  
Adiabatic Shear ◽  
Interstitial Free ◽  
Adiabatic Shear Bands ◽  
Microstructural Investigation ◽  
Interstitial Free Steel

Deformation and Failure Mechanisms of Austenitic Piping Under the Influence of Oxyhydrogen Reactions

2016 ◽  
Author(s):  
Stefan Offermanns ◽  
Stefan Weihe
Keyword(s):  
Failure Mechanisms ◽  
Shear Bands ◽  
Adiabatic Shear ◽  
Material Behavior ◽  
Inert Gas ◽  
Materials Testing ◽  
Failure Model ◽  
Adiabatic Shear Bands ◽  
Deformation And Failure ◽  
Gas Component

The present paper deals with the deformation and failure mechanisms of austenitic piping under the influence of oxyhydrogen reactions for the safety evaluation of incident scenarios in technical installations based on previous work of the author [1–5]. For the characterization of the processes, detonation tests performed at the Materials Testing Institute University of Stuttgart (MPA Stuttgart) have been used. The aim of these experiments was to study the detonation processes in head spray cooling piping of boiling water reactors. The experiments were performed on austenitic pipes with an outer diameter of O. D. = 114.3 mm and various wall thicknesses. Oxyhydrogen was used in its stoichiometric ratio of 2H2+O2 mixed with various amounts of an inert gas component. These tests have shown that less amounts of reactive gas may result in a stronger reaction of the pipe structure. This observation is attributed to the influence of the so-called overdriven detonation. Depending on the ratio of oxyhydrogen to the inert gas component and the pipe-wall thickness, adiabatic shear bands can occur in the piping structure. Adiabatic shear bands are very narrow zones with intense localized shear deformations due to the conversion of a significant portion of strain energy into heat. In order to describe this phenomenon numerically, a strain-based failure model was used which can reflect material damage over a wide range of different stress states. However, it has shown that damage of the studied material depends significantly on the Lode angle. Furthermore, no clear dependence of the failure limit on the loading rate has been found for the studied material. For the constitutive description of the material behavior under the occurring loading rates and temperatures suitable material models were selected and the required parameters have been evaluated experimentally and verified by numerical methods. With the aid of this constitutive description of the material behavior and the failure model numerical simulations of the detonation tests were carried out.

Influence of Cutting Conditions on the Width of Adiabatic Shear Bands: An Investigation Using Finite Element Simulation

2013 ◽  
Vol 820 ◽  
pp. 194-199
Author(s):  
Tao Cui ◽  
Hong Wei Zhao ◽  
Ye Tian ◽  
Chuang Liu
Keyword(s):  
High Speed ◽  
Shear Bands ◽  
Chip Thickness ◽  
Rake Angle ◽  
Adiabatic Shear ◽  
Adiabatic Shear Bands ◽  
High Speed Cutting ◽  
Model Combining ◽  
Cutting Velocity ◽  
Microstructure Prediction

In this paper, a novel model combining the microstructure prediction model and a modified constitutive model of the Johnson-Cook (JC) model was developed and embedded into FEM software via the user subroutine. The chip formation and microstructure evolution in high speed cutting of Ti-6Al-4V alloy were simulated. The results indicated that dynamic recrystallization mainly happened in adiabatic shear bands (ASBs), where the grain size had a big decline. Then FEM simulations were carried out to investigate the effect of cutting velocity, uncut chip thickness, and the rake angle on the ASBs width of the serrated chips. It can be concluded that the width of ASB increases with the increasing of cutting depth and cutting velocity, and decreases with the increasing of rake angle of the tool.

Microstructural Evolution from Shaped Charge through Steel Plates

2014 ◽  
Vol 566 ◽  
pp. 344-349
Author(s):  
M. Nabil Bassim ◽  
S. Boakye-Yiadom ◽  
Manon Bolduc
Keyword(s):  
Shock Wave ◽  
Molten Metal ◽  
Microstructural Evolution ◽  
Shear Bands ◽  
Adiabatic Shear ◽  
Shaped Charge ◽  
Steel Plates ◽  
Adiabatic Shear Bands ◽  
Armour Steel

A set of 18 armour steel plates were stacked on top of each other and subjected to shape charges that went through the plates and created a hole that decreased in diameter as it went through consecutive plates. Afterwards, the plates were examined and the hardness near the hole and away from the hole was taken to determine the effect of the passing of the shaped charge through the plates. Also, specimens from the walls of the holes were taken to determine changes in the microstructure due to the shock wave and the resulting excessive heating from the shape charge. It was observed that the shock wave produced significant changes in the microstructure resulting in the appearance adiabatic shear bands (ASBs). These ASBs persisted in holes in plates placed further down the stack (up to 8thin the stack). More complex microstructural mechanisms are thought to take place as opposed to erosion from the flow of the molten metal through the holes in the plates.

Analysis and characterization by electron backscatter diffraction of microstructural evolution in the adiabatic shear bands in Fe–Cr–Ni alloys

2009 ◽  
Vol 24 (8) ◽  
pp. 2617-2627 ◽  
Author(s):  
Huajie Yang ◽  
Yongbo Xu ◽  
Yasuaki Seki ◽  
Vitali F. Nesterenko ◽  
Marc André Meyers
Keyword(s):  
Microstructural Evolution ◽  
Electron Backscatter Diffraction ◽  
Shear Bands ◽  
Adiabatic Shear ◽  
Adiabatic Shear Bands ◽  
Localized Deformation ◽  
Ni Alloys ◽  
Electron Backscatter ◽  
Backscatter Diffraction ◽  
Equiaxed Grains

The microstructural evolution inside adiabatic shear bands in Fe–Cr–Ni alloys dynamically deformed (strain rates > 104 s−1) by the collapse of an explosively driven, thick-walled cylinder under prescribed strain conditions was examined by electron backscatter diffraction. The observed structure within the bands consisted of both equiaxed and elongated grains with a size of ∼200 nm. These fine microstructures can be attributed to recrystallization; it is proposed that the elongated grains may be developed simultaneously with localized deformation (dynamic recrystallization), and the equiaxed grains may be formed subsequently to deformation (static recrystallization). These recrystallized structures can be explained by a rotational recrystallization mechanism.

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