Deformation behaviour and dislocation structures upon stress reversal in polycrystalline aluminium

Hasegawa, Tadashi; Yakou, Takao; Karashima, Seiichi

doi:10.1016/0025-5416(75)90159-7

Cited by 231 publications

(101 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A large strain offset captures the behaviour of permanent softening, as depicted by the stress σ ps in Figure 1. This stress is calculated from the difference between the values for the flow stress at continued straining and at reversed straining, σ f -|σ r |, defined by points F and I' in In previous work [10,11] transmission electron microscopy (TEM) was performed at different stages of the transient process upon strain reversal to explore the evolution of the dislocation density and arrangement. The dislocation arrangement associated with the transient softening could arise from features such as sub-structure disintegration, back flow of the piled-up dislocations, and dislocation interactions with solute atoms and/or second phase precipitates.…”

Section: Introductionmentioning

confidence: 99%

Role of the misfit stress between grains in the Bauschinger effect for a polycrystalline material

Chen

Wang

et al. 2015

Acta Materialia

View full text Add to dashboard Cite

. (2015) Role of the misfit stress between grains in the Bauschinger effect for a polycrystalline material. Acta Materialia, http://dx.doi.org/10.1016/j.actamat. .11.021 DOI 10.1016/j.actamat.2014.11.021 ISSN 1359 Publisher: Elsevier Copyright © and Moral Rights are retained by the author(s) and/ or other copyright owners. A copy can be downloaded for personal non-commercial research or study, without prior permission or charge. This item cannot be reproduced or quoted extensively from without first obtaining permission in writing from the copyright holder(s). The content must not be changed in any way or sold commercially in any format or medium without the formal permission of the copyright holders. This document is the author's post-print version, incorporating any revisions agreed during the peer-review process. Some differences between the published version and this version may remain and you are advised to consult the published version if you wish to cite from it. AbstractThe role of misfit stress on kinematic hardening under reversed straining of a Type 316H austenitic stainless steel has been investigated by using the neutron diffraction technique combined with in-situ deformation. Initial misfit stresses, often referred to an intergranular internal stresses, were created by the tensile pre-straining at high temperature. The misfit stresses at the length-scale of grain families, measured by neutron diffraction, were shown to be a function of the magnitude of the tensile prestrain. The pre-strained specimens were further subjected to either continued (tensile) straining or reversed (compressive) straining at room temperature. In-situ neutron diffraction measurements were undertaken to monitor the change of the misfit stresses during loading. The macroscopic stress-strain behaviour was used to derive isotropic and kinematic hardening stresses developed in the pre-strained specimens. Resultsshow that the change of the transient softening stress towards a zero value is accompanied by a decrease in the change of the misfit stresses. A multi-scale selfconsistent model has been developed to assist in understanding the measured change of the misfit stresses when subjecting the material to strain reversal. An important conclusion is that the origin of the kinematic hardening of Type 316H austenitic stainless steel arises from the misfit stress between grains.

show abstract

Section: Introductionmentioning

confidence: 99%

Role of the misfit stress between grains in the Bauschinger effect for a polycrystalline material

Chen

Wang

et al. 2015

Acta Materialia

View full text Add to dashboard Cite

show abstract

“…Since metal forming processes involve both large plastic strains and severe strainpath changes, an adequate modeling of this induced flow anisotropy is crucial for the proper prediction of residual stresses and, consequently, of the amount of springback in structural components. Starting with Ghosh and Backofen [8] who investigated the influence of different strain paths on the deformation behavior and observed a variation of the work-hardening rate in sheet metals depending on the pre-deformation, Hasegawa et al [10] related the decrease in the rate of work-hardening after a reverse in strain direction to the changes in the substructure, namely the partial dissolution of cells and a slight decrease in the corresponding dislocation density. Strauven and Aernoudt [32] also followed the changes in the microstructure and related it to the transient regions of work-hardening observed in tension-compression tests.…”

Section: Introductionmentioning

confidence: 99%

Phenomenological modeling of anisotropy induced by evolution of the dislocation structure on the macroscopic and microscopic scale

et al. 2011

View full text Add to dashboard Cite

This work focuses on the modeling of the evolution of anisotropy induced by the development of the dislocation microstructure. A model formulated at the engineering scale in the context of classical metal plasticity and a model formulated in the context of crystal plasticity are presented. Images obtained by transmission-electron microscopy (TEM) show the influence of the strain path on the evolution of anisotropy for the case of two common materials used in sheet metal forming, DC06 and AA6016-T4. Both models are capable of accounting for the transient behavior observed after changes in loading path for fcc and bcc metals. The evolution of the internal variables of the models is correlated with the evolution of the dislocation structure observed by TEM investigations.

show abstract

“…However, Hasegawa et al 27) have shown that in the case of reversal deformation, upon reversing the deformation direction (e.g. from CW to CCW and back), the density of dislocations decreases up to 16% and even low angle boundaries formed at the first step can be dissolved.…”

Section: Discussionmentioning

confidence: 99%

Comparative Analysis of Plastic Flow and Grain Refinement in Pure Aluminium Subjected to Simple Shear-Based Severe Plastic Deformation Processing

et al. 2012

View full text Add to dashboard Cite

In the present work, effects of loading scheme and strain reversal on structure and hardness evolution have been studied by using high pressure torsion (HPT) and twist extrusion (TE) techniques. High purity aluminium (99.99%) was processed at room temperature up to a maximum total equivalent strain of ¾ max μ 8 by TE, and HPT in monotonic and reversal deformation modes with strain increment ¦¾ max = 1. Minimum subgrain sizes reached in this study were 1.6 µm for TE and 1.1 µm for HPT. It was revealed that microstructural change with straining was a common consequence of severe plastic deformation (SPD) processing and was not affected significantly by the loading scheme. Among the SPD methods used in this study, HPT in monotonic regime produced the smallest grain size, while the most homogeneous microstructure was obtained by TE due to specific vortex-like flow field imposed by the tool geometry.

show abstract

Deformation behaviour and dislocation structures upon stress reversal in polycrystalline aluminium

Cited by 231 publications

References 13 publications

Role of the misfit stress between grains in the Bauschinger effect for a polycrystalline material

Role of the misfit stress between grains in the Bauschinger effect for a polycrystalline material

Phenomenological modeling of anisotropy induced by evolution of the dislocation structure on the macroscopic and microscopic scale

Comparative Analysis of Plastic Flow and Grain Refinement in Pure Aluminium Subjected to Simple Shear-Based Severe Plastic Deformation Processing

Contact Info

Product

Resources

About