Characteristics of the propagating deformation bands associated with the Portevin–Le Chatelier effect in an Al–Zn–Mg–Cu alloy

Thévenet, David; Mliha-Touati, M.; Zeghloul, A.

doi:10.1016/s0921-5093(00)00988-6

Cited by 31 publications

(8 citation statements)

References 13 publications

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“…From a macroscopic perspective, it is related to a negative strain rate sensitivity that leads to localized bands that are simulated [25]. Many experimental studies [26] however are based upon average strain measurements. There are also fullfield displacement measurements performed by using, for instance, laser speckle interferometry [27].…”

Section: Methodsmentioning

confidence: 99%

“Finite-Element” Displacement Fields Analysis from Digital Images: Application to Portevin–Le Châtelier Bands

2006

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A new methodology is proposed to estimate displacement fields from pairs of images (reference and strained) that evaluates continuous displacement fields. This approach is specialized to a finite-element decomposition, therefore providing a natural interface with a numerical modeling of the mechanical behavior used for identification purposes. The method is illustrated with the analysis of Portevin-Le Châtelier bands in an aluminum alloy sample subjected to a tensile test. A significant progress with respect to classical digital image correlation techniques is observed in terms of spatial resolution and uncertainty.

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Section: Methodsmentioning

confidence: 99%

“Finite-Element” Displacement Fields Analysis from Digital Images: Application to Portevin–Le Châtelier Bands

2006

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“…The Portevin Le‐Chatelier effect has been largely studied in aluminum alloys, being well known in AlMg 5 , AlCuMgPb, AlZnMg and AlMgSi alloys, . Studies are being conducted currently in Al‐4 at%Cu, AlMg, AlZnMgCu and AlZnMgCuZr alloys in order to understand the role of the type of precipitated, aging time and temperature on the serrated yielding . Although this phenomenon can be in most cases accompanied by a negative strain rate exponent (m), tests were carried out varying the tensile rate and this alloy do not have this characteristic, presenting a positive value of m. This phenomenon was, however, not in the main focus of this work and was not extensively studied, needing additional work to be fully explained.…”

Section: Resultsmentioning

confidence: 99%

Microstructure of a recycled AA7050 alloy processed by spray forming followed by hot extrusion and rotary swaging

Guerra

Ellendt

Uhlenwinkel

et al. 2014

Materialwissenschaft Werkst

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The aim of this study is to evaluate the microstructure of a recycled AA7050 alloy processed by spray forming followed by hot extrusion and swaging. Machining chips from an aircraft manufacturer were used as raw material. The microstructure was investigated by optical microscopy (MO) and scanning electronic microscopy (SEM). The spray formed deposit was homogenized at 743 K, 8 h, extruded at 693 K with a deformation rate of 0.1 s–1 and an extrusion rate of 156:1, producing a bar with 8.0 mm in diameter. Due to a specific combination of high extrusion temperature and deformation rate, partial recrystallization occurred and different grain sizes were obtained through the extruded cross section. After extrusion, the 8.0 mm bar was processed by rotary swaging in several steps up to a 2.0 mm final diameter. The resulting microstructure revealed a cold worked structure, with no recrystallization. Tensile tests were performed in both cases and the slant type of fracture reveals that Portevin Le‐Chatelier effect took place in this alloy. Moreover, the efficacy of extrusion and rotary swaging parameters to reduce the porosity, intrinsic to the spray form process, was analyzed, as well the distribution of intermetallic particles.

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“…This task poses in fact great technical difficulties because of the short duration of a single PLC band, underneath 10 ms, and can be undertaken only with high‐speed cameras. Until now, the strain rate inside a PLC band could only be measured with small strain gauges [19] or estimated from some boundary conditions [18], but we propose here a full‐field technique based on picture sequences taken with a high‐speed camera at the rate of 1000 fps. This full‐field measure permits tensorial calculations and therewith the determination of the shear rate, which is of relevance considering that the bands originate from a shearing mechanism.…”

Section: Applicationsmentioning

confidence: 99%

Full‐Field Strain Rate Measurement by White‐Light Speckle Image Correlation

Broggiato

Casarotto

Prete

et al. 2009

Strain

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This paper explains a numerical procedure to process sequences of digital images and to return a full‐field evaluation of the strain rate. The processing procedure is based on a nonlinear least squares fitting performed globally, on the whole image, and simultaneously on several images. The use of a highly optimised code allows the analysis of long sequences in a few minutes. The results of calculations are presented as movies built by blending the colour maps of the measured strain field with the specimen pictures used in the correlation procedure. Our application is focused on studying the plastic behaviour of metals and, in particular, on highlighting any transient phenomena that might occur during yielding and strain‐hardening phases on thin sheets used in the manufacture of sheet metals. A typical example for such phenomena is the Portevin‐Le Châtelier effect, a repetitive yielding of alloys during plastic deformation.

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Characteristics of the propagating deformation bands associated with the Portevin–Le Chatelier effect in an Al–Zn–Mg–Cu alloy

Cited by 31 publications

References 13 publications

“Finite-Element” Displacement Fields Analysis from Digital Images: Application to Portevin–Le Châtelier Bands

“Finite-Element” Displacement Fields Analysis from Digital Images: Application to Portevin–Le Châtelier Bands

Microstructure of a recycled AA7050 alloy processed by spray forming followed by hot extrusion and rotary swaging

Full‐Field Strain Rate Measurement by White‐Light Speckle Image Correlation

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