Transcript overview_crystalmechanics

Micro-scale single crystal Bauschinger effect and reversible
plasticity in copper during bending
E. Demir*, D. Raabe
* Cornell Univ. Rhodes Hall, Mechanical & Aerospace Engr. Dept.
Düsseldorf, Germany
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[email protected]
MRS Fall Conference
1. Dec. 2010
Boston, USA
Overview
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Introduction
 Question: Bauschinger effect* also size dependent ?
 Relevant in metal forming and cyclic straining
(small parts AND small scale microstructures)
 Approach: Bending and stretching
experiments on a Cu single crystal
* Bauschinger effect: flow strength change upon load path change (reversal)
Demir, Raabe, Acta Materialia 58 (2010) 6055
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Explanations of the Bauschinger effect
Demir, Raabe, Acta Materialia 58 (2010) 6055
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Overview
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Experiment
E. Demir, D. Raabe, Acta Materialia 58 (2010) 6055
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Set-up of experiment
E. Demir, D. Raabe, Acta Materialia 58 (2010) 6055
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Overview
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Stress-strain results
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Microstructure and mechanical Bauschinger effect
straightening (backward)
Kernal average misorientation
bending (forward)
Mechanical Bauschinger effect: yield stress drop upon load path change
orientation
map change
Microstructural Bauschinger effect: microstructure reversibility upon
load path
Kernal average misorientation
orientation map
Demir et al. Acta Mater. 57 (2009) 559 ; M. Calcagnotto et al. Mater. Sc. Engin. A 527 (2010) 2738
Demir et al.: Acta Materialia 58 (2010) 6055
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Microstructure and mechanical Bauschinger effect
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Overview
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Conclusions
Roters et al. Acta Mater.58 (2010)
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