A hybrid model for studying the size effects on flow stress in micro - forming with the consideration of grain hardening

Singh, M; Hossain, A; Wei, D

A hybrid model for studying the size effects on flow stress in micro - forming with the consideration of grain hardening

Singh, M Hossain, A Wei, D

Permalink

Publication Type:: Journal Article
Citation:: Key Engineering Materials, 2019, 794 KEM pp. 97 - 104
Issue Date:: 2019-01-01

Open Access

Copyright Clearance Process

Recently Added
In Progress
Open Access

This item is open access.

Adobe PDF

Download Accepted Manuscript VersionAdobe PDF (1.34 MB)

View on publisher's site

View statistics

Full metadata record

Field	Value	Language
dc.contributor.author	Singh, M	en_US
dc.contributor.author	Hossain, A	en_US
dc.contributor.author	Wei, D https://orcid.org/0000-0002-4247-8905	en_US
dc.date.issued	2019-01-01	en_US
dc.identifier.citation	Key Engineering Materials, 2019, 794 KEM pp. 97 - 104	en_US
dc.identifier.isbn	9783035713626	en_US
dc.identifier.issn	1013-9826	en_US
dc.identifier.uri	http://hdl.handle.net/10453/137471
dc.description.abstract	© 2019 Trans Tech Publications Ltd, Switzerland. Size effects extremely exist in the metal micro-forming process. When a deformation process scales down to micro scale, the appearances of geometry size and single grain size starts to play a major role in deformation. Generally, the size effects are unavoidable in the experimental work and cannot be neglect in the optimization of micro-forming processes. In this paper, size effect on flow stress is investigated in the form of the coupled effect of workpiece geometry (sample thickness) and grain size, (T/D) by the micro tensile test of pure copper foil. Following the previous approaches, a new hybrid material model is projected to describe the hardening behavior of grains in polycrystalline material. Tensile tests performed on the copper foil with constant thickness and width, while to get dissimilar grain sizes, the foil annealed for different times. The ratio of thickness to grain size (T/D) is limited to larger than 1 (T/D>1). A hybrid material model is proposed and established based on grain heterogeneity and sample thickness. The hybrid material model builds a relationship between the surface layer and sheet interior. The hybrid material model developed by the strain gradient theory in which the dislocation cell structure, cell densities (interior and wall) engaged to define the polycrystalline aggregate and calculated the dislocations in a grain (grain interior and grain wall). The results show that flow stress varies with the different values of T/D, but with an increase of the share of the grains flow stress start to decreases. After applying the hybrid material model of flow stress, the micro-tensile test of copper foil is simulated by finite element method. The simulation outcomes well matched with experimental results.	en_US
dc.relation.ispartof	Key Engineering Materials	en_US
dc.relation.isbasedon	10.4028/www.scientific.net/KEM.794.97	en_US
dc.rights	info:eu-repo/semantics/openAccess
dc.subject.classification	Materials	en_US
dc.title	A hybrid model for studying the size effects on flow stress in micro - forming with the consideration of grain hardening	en_US
dc.type	Journal Article
utslib.citation.volume	794 KEM	en_US
utslib.for	0912 Materials Engineering	en_US
utslib.for	0913 Mechanical Engineering	en_US
utslib.for	09 Engineering	en_US
pubs.embargo.period	Not known	en_US
pubs.organisational-group	/University of Technology Sydney
pubs.organisational-group	/University of Technology Sydney/Faculty of Engineering and Information Technology
pubs.organisational-group	/University of Technology Sydney/Faculty of Engineering and Information Technology/School of Mechanical and Mechatronic Engineering
utslib.copyright.status	open_access	*
pubs.publication-status	Published	en_US
pubs.volume	794 KEM	en_US

Abstract:

© 2019 Trans Tech Publications Ltd, Switzerland. Size effects extremely exist in the metal micro-forming process. When a deformation process scales down to micro scale, the appearances of geometry size and single grain size starts to play a major role in deformation. Generally, the size effects are unavoidable in the experimental work and cannot be neglect in the optimization of micro-forming processes. In this paper, size effect on flow stress is investigated in the form of the coupled effect of workpiece geometry (sample thickness) and grain size, (T/D) by the micro tensile test of pure copper foil. Following the previous approaches, a new hybrid material model is projected to describe the hardening behavior of grains in polycrystalline material. Tensile tests performed on the copper foil with constant thickness and width, while to get dissimilar grain sizes, the foil annealed for different times. The ratio of thickness to grain size (T/D) is limited to larger than 1 (T/D>1). A hybrid material model is proposed and established based on grain heterogeneity and sample thickness. The hybrid material model builds a relationship between the surface layer and sheet interior. The hybrid material model developed by the strain gradient theory in which the dislocation cell structure, cell densities (interior and wall) engaged to define the polycrystalline aggregate and calculated the dislocations in a grain (grain interior and grain wall). The results show that flow stress varies with the different values of T/D, but with an increase of the share of the grains flow stress start to decreases. After applying the hybrid material model of flow stress, the micro-tensile test of copper foil is simulated by finite element method. The simulation outcomes well matched with experimental results.

Please use this identifier to cite or link to this item:

http://hdl.handle.net/10453/137471