The Positive Role of Back-Pressure in Equal Channel Angular Extrusion

Rimma Lapovok

doi:10.4028/www.scientific.net/MSF.503-504.37

Paper Titles

Nanocrystalline Structure in Steels Produced by Various Severe Plastic Deformation Processes
p.11

Developing a Model for Grain Refinement in Equal-Channel Angular Pressing
p.19

Effect of Initial Grain Size, Die Angle and Pass Sequence on the Formation of Ultrafine Grain Structure in Cu by ECAP
p.25

Local Investigations of the Mechanical Properties of Ultrafine Grained Metals by Nanoindentations
p.31

The Positive Role of Back-Pressure in Equal Channel Angular Extrusion
p.37

On the Grain Refinement Mechanisms in SPD – Applying High Resolution Electron Microscopy and the LEDS Approach
p.45

On the Microstructure of HPT Processed Cu under Variation of Deformation Parameters
p.51

Deformation Induced Vacancies with Severe Plastic Deformation: Measurements and Modelling
p.57

Influence of Processing Parameters on Texture and Microstructure in Aluminum after ECAP
p.65

HomeMaterials Science ForumMaterials Science Forum Vols. 503-504The Positive Role of Back-Pressure in Equal...

The Positive Role of Back-Pressure in Equal Channel Angular Extrusion

Abstract:

Equal Channel Angular Extrusion (ECAE) has become a very popular tool for studying the evolution of microstructure and properties under severe plastic deformation. It is believed that the stress-strain characteristics are uniform in a cross-section of the billet and this uniformity of the stress-strain distribution ensures the uniformity of microstructure and mechanical properties in ECAE processed billet. However, some experimental data such as the fracture of the extruded billet, which is initiated at the inner surface of the sample, has caused doubts about uniformity of stress-strain distribution. This non-uniformity has been proved recently by Finite Element Simulation. In this paper the studies of the positive role of the applied back-pressure during ECAE are reviewed and the influence of a back-pressure on the uniformity of the stress-strain distribution, strain localisation, die corner filing, and the prevention of fracture is shown. The effect of back-pressure on grain refinement and improvement in mechanical properties is emphasized. The paper summarises our results from over seven years of work using a unique machine for ECAE with computer-controlled back-pressure and velocity of the backward punch.

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Periodical:

Materials Science Forum (Volumes 503-504)

Pages:

37-44

DOI:

https://doi.org/10.4028/www.scientific.net/MSF.503-504.37

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Online since:

January 2006

Authors:

Rimma Lapovok

Keywords:

Back Pressure, Damage Accumulation, Equal Channel Angular Extrusion (ECAE), Fracture, Mechanical Property

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