CUI Jianzhong MA Longxiang Northeast University of Technology
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Shenyang
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China Department of Metals Forming
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Northeast University of Technology
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Shenyang
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China
金属学报(英文版)
The method controlling grain shape in TMT processing and the effect of grain shape on char- acteristic parameters in superplastic deformation were discussed.The accommodation velocity of grahl boundary sliding,which is the dominant mechanism in superplastic deformation,and the contribution of each mechanism to the total strain,as influenced by grain shape,were ana- lyzed.Grain shape has been shown to be an essential structural factor for superplasticity.Then an analysis was made about the effect of grain shape on the region transition strain rate so that a new concept,critical aspect for superplasticity,was worked out.These predictions were compared with the measured results in an Al-Zn-Mg alloy.
关键词:
superplastic deformation
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H.-M. Huang
,
J. Pan and S. C. Tang 1) Mechanical Engineering and Applied Mechanics
,
The University of Michigan Ann Arbor
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MI 48109
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USA 2) Ford Research Laboratory
,
Ford Motor Company Dearborn
,
MI 48121
,
USA
金属学报(英文版)
An approximate macroscopic yield criterion for anisotropic porous sheet metals is adopted in a failure prediction methodology that can be used to investigate the failure of sheet metals under forming operations. This failure prediction methodology is developed based on the Marciniak-Kuczynski approach by assuming a slightly higher void volume fraction inside randomly oriented imperfecte analysis. Here, a nonproportional deformation history including relative rotation of principal stretch directions is identified in a selected critical element of an aluminum sheet from a FEM fender forming simulation. Based on the failure prediction methodology, the failure of the critical sheet element is investigated under the non-proportional deformation history. The results show that thiven non-proportional deformation history.
关键词:
sheet metal forming
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