Effect of back pressure on material flow and texture in ECAP of aluminum

Panigrahi, Ajit; Scheerbaum, N.; Chekhonin, Paul; Scharnweber, Juliane; Beausir, Benoît; Hockauf, Matthias; Sankaran, Sindhuja; Skrotzki, Werner

doi:10.1088/1757-899x/63/1/012153

Cited by 11 publications

(4 citation statements)

References 22 publications

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“…Consequently, microstructure and texture formation is non-uniform across the billet. This has been demonstrated by the present author and coworkers 1430) in some ECAP deformed face-centered cubic (FCC) and hexagonal close-packed (HCP) metals, and also by models based on visioplasticity, 13,3034) finite element methods (FEM), both in 2-D and 3-D, 13,30,3555) and by slip line theory 56,57) providing evidences of inhomogeneous deformation during ECAP. In general, plastic deformation takes place in the PDZ the shape of which sensitively depends on factors such as die geometry (die angle and corner roundness), processing conditions (contact friction, back pressure (BP), temperature and pressing speed, ECAP route and number of passes) and plastic properties of the material itself.…”

Section: Introductionmentioning

confidence: 53%

“…The shear angle is about 64°. 30) of 11% and 6%, corresponding to hardness gradients of 5.8 MPa/mm and 3.4 MPa/mm, for BPs of 0 MPa and 200 MPa, respectively. 81) Brinell hardness measurements have been also done by Frint et al 63) on oxygen free high conductivity copper (purity better than 4N) ECAPed 4 and 8 passes route E (successive 180°and 90°rotations) through a laboratory scale (15 mm © 15 mm) and large scale (50 mm © 50 mm) friction-reduced die applying a back pressure of 75 MPa.…”

Section: Back Pressurementioning

confidence: 98%

“…73) With increasing BP there is a decrease in average cell size, increase in cell wall thickness and increase of dislocation density within the cells and cell walls. Moreover, 30) For this a sophisticated large-scale ECAP tool (50 mm © 50 mm) especially designed for low friction was used with moving outer walls and sliding bottom. 63) The flow pattern was made visible by a grid scribed on the transverse section of a billet split in the middle.…”

Section: Back Pressurementioning

confidence: 99%

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Deformation Heterogeneities in Equal Channel Angular Pressing

Skrotzki¹

2019

Mater. Trans.

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Equal channel angular pressing (ECAP) is a severe plastic deformation (SPD) technique leading to refinement of the grain size of materials to submicron or even nano-size length scales. As a result SPD processed materials simultaneously possess high strength and moderate ductility and therefore have a high potential for technical applications. Because of this, much work has been devoted to the evolution of microstructure and texture and their relation to the mechanical properties. However, pressing materials through an angled channel is a complicated deformation process leading to deformation heterogeneities across the billet cross section manifested in gradients of microstructure and texture. Therefore, it is the aim of the present paper to give an overview focusing on the ECAP specific deformation heterogeneities and their related strength gradient in the billets produced. Based on the results reported, which are gained from experiment and simulation, some general conclusions on minimizing the deformation heterogeneities in ECAP are drawn. [

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Section: Introductionmentioning

confidence: 53%

Section: Back Pressurementioning

confidence: 98%

Section: Back Pressurementioning

confidence: 99%

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Deformation Heterogeneities in Equal Channel Angular Pressing

Skrotzki¹

2019

Mater. Trans.

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“…As strengthening mechanisms many metals are conformable with cold working, solid solution, and precipitation/dispersion hardening. Recently, as mentioned in few publications by Skrotzki W. [19], Quang P. [20][21][22][23] the light metals as Al, Mg or Ti show a high potential for technical applications in the automotive and aircraft industry, ocean exploration and high-end handheld electronics. Although the effect of back pressure during the ECAP process has been illustrated in experiments and FEM models on a variety of metals and alloys, comprehensive knowledge of flow ability and texture formation is still limited.…”

Section: √3 Cot φmentioning

confidence: 99%

The ECAP Process Simulation and Experiments with Different Back Pressures for Magnesium Alloy

Pham

2022

J. Phys.: Conf. Ser.

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According to this study, the ECAP process with different BP is performed on the engineering magnesium alloy (AZ31). The effect of BP on the strain condition and flow paths may differ as the statically deformed portion of the sample passes through the strain zone. The BP application of 25, 50 and 100 MPa brings about the forward typical shear rotation of structural components in the horizontal direction. The complex (20 x 20 x 200) mm3 ECAP engine is applied with movable outer walls and specially designed sliding bottoms for low friction (moving die). The flow model is made by a cubic flow net of the DEFORM software tool on the workpiece. Structural features and initial micro-hardness measurements made on the x and y planes of the workpiece also received a special attention. Since BP leads to increased density the micro-hardness could be improved and ascribed to the change in texture.

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Multi-scale investigation of microstructure and texture evolution during equal channel angular pressing of silver

Suwas,

Skrotzki,

Scheerbaum

et al. 2024

J Mater Sci

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A multi-scale investigation was carried out on pure silver subjected to equal channel angular pressing up to 3 passes. Microstructure and texture were examined using scanning and transmission electron microscopy as well as diffraction of neutron and high-energy synchrotron radiation. The evolution of the deformation substructure in the material is in accordance with its low stacking fault energy followed by restoration mechanisms leading to overall microstructural refinement. The restoration mechanism sets in as early as after 3 passes. Twinning involved in the deformation process supports grain refinement through mechanisms of dynamic recrystallization involving strain-induced boundary migration contributing to a steady-state grain size. The global texture, as measured by neutron diffraction, forms through a twin-assisted deformation mechanism. The texture is found heterogeneous through thickness. Graphical abstract

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Effect of back pressure on material flow and texture in ECAP of aluminum

Cited by 11 publications

References 22 publications

Deformation Heterogeneities in Equal Channel Angular Pressing

Deformation Heterogeneities in Equal Channel Angular Pressing

The ECAP Process Simulation and Experiments with Different Back Pressures for Magnesium Alloy

Multi-scale investigation of microstructure and texture evolution during equal channel angular pressing of silver

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