Manufacturing a curved profile with fine grains and high strength by differential velocity sideways extrusion
File(s)2019 Curved Extrusion Accepted.pdf (2.67 MB)
Accepted version
Author(s)
Zhou, W
Yu, J
Lin, J
Dean, TA
Type
Journal Article
Abstract
For structural and aerodynamic reasons, curved profiles are widely used in the transport industry for manufacturing lightweight structures. In the present work, a curved AA1050 bar with fine grains and high strength was manufactured by a novel forming technique, differential velocity sideways extrusion (DVSE). The evolution of grain structure and micro-texture during DVSE and the mechanical properties of the formed bar were studied, and the grain refinement mechanism was revealed. Due to the severe strains arising in the process, (greater than that for conventional one pass equal channel angular extrusion), significant grain refinement in the curved bar (grain size ∼3 μm) was achieved from the original billet (grain size ∼357 μm) in one extrusion operation. Coarse band-like structures containing subgrains with low angle boundaries in the shearing zone gradually transformed into fine shear band-like structures containing equiaxed (sub)grains with a mixture of low and high angle boundaries. The fine shear band-like structures inclined approximately along the shear intersection planes. Severe plastic deformation induced a high dislocation density that initiated subgrain walls with low angle boundaries, which gradually transformed into grain boundaries with high misorientation, indicating that refinement of AA1050 grains in the DVSE process is due mainly to continuous dynamic recrystallization (cDRX). Due to the appearance of greater effective strain on the inner bend of the extruded bar, the grain refinement degree and high angle boundary fraction of the material on the inner bend are slightly greater than those of the material on the outside. DVSE resulted in a weak C-type shear-texture component which can be determined by a proper rotation of the negative simple shear texture. Compared with the billet, significant increase of the hardness, yield strength and ultimate tensile strength by 134.8%, 354.0% and 116.8% respectively was achieved in the formed curved bar, although the elongation to fracture was decreased by 60.0%.
Date Issued
2019-05-01
Date Acceptance
2019-03-03
Citation
International Journal of Machine Tools and Manufacture, 2019, 140 (1), pp.77-88
ISSN
0890-6955
Publisher
Elsevier
Start Page
77
End Page
88
Journal / Book Title
International Journal of Machine Tools and Manufacture
Volume
140
Issue
1
Copyright Statement
© 2019 Elsevier Ltd. All rights reserved. This manuscript is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International Licence http://creativecommons.org/licenses/by-nc-nd/4.0/
Identifier
https://www.sciencedirect.com/science/article/pii/S0890695519300173
Subjects
Science & Technology
Technology
Engineering, Manufacturing
Engineering, Mechanical
Engineering
Differential velocity sideways extrusion (DVSE)
Profile bending
Aluminium alloy 1050
Severe plastic deformation (SPD)
Grain refinement
Continuous dynamic recrystallization (cDRX)
SEVERE PLASTIC-DEFORMATION
MECHANICAL-PROPERTIES
CHANNEL
EVOLUTION
Industrial Engineering & Automation
0910 Manufacturing Engineering
Publication Status
Published
Date Publish Online
2019-03-07