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Thermally activated flow in soft and hard regions: Getting information on work hardening strain and recovery strain from rate change tests

Blum, W. and Eisenlohr, P. and Prell, M. and Durst, Karsten (2015):
Thermally activated flow in soft and hard regions: Getting information on work hardening strain and recovery strain from rate change tests.
In: KOVOVE MATERIALY-METALLIC MATERIALS, REDAKCIA KOVOVE MATERIALY, Slovakia, pp. 199-205, 53, (4), ISSN 0023-432X, [Article]

Abstract

The investigation of thermally activated glide processes by stress reduction tests is reviewed. The tests reveal that two mechanisms of inelastic deformation are superimposed, namely dislocation glide connected with work hardening by defect storage and recovery strain related with relaxation of internal stresses and defect recovery. The coupling of the two is proposed to be modeled within the composite model. A new kind of transient testing is proposed that combines the conventional rate change test with an intermediate stress reduction. Its application to nanocrystalline Ni shows similarity of the main parameters of thermally activated dislocation glide and recovery strain found for conventional pure single and polycrystals: spacings of thermal obstacles in units of free dislocation spacing approximate to 1, back flow starting after approximate to 20 % stress reduction, similar magnitude of relative contribution and stress dependence of recovery strain.

Item Type: Article
Erschienen: 2015
Creators: Blum, W. and Eisenlohr, P. and Prell, M. and Durst, Karsten
Title: Thermally activated flow in soft and hard regions: Getting information on work hardening strain and recovery strain from rate change tests
Language: English
Abstract:

The investigation of thermally activated glide processes by stress reduction tests is reviewed. The tests reveal that two mechanisms of inelastic deformation are superimposed, namely dislocation glide connected with work hardening by defect storage and recovery strain related with relaxation of internal stresses and defect recovery. The coupling of the two is proposed to be modeled within the composite model. A new kind of transient testing is proposed that combines the conventional rate change test with an intermediate stress reduction. Its application to nanocrystalline Ni shows similarity of the main parameters of thermally activated dislocation glide and recovery strain found for conventional pure single and polycrystals: spacings of thermal obstacles in units of free dislocation spacing approximate to 1, back flow starting after approximate to 20 % stress reduction, similar magnitude of relative contribution and stress dependence of recovery strain.

Journal or Publication Title: KOVOVE MATERIALY-METALLIC MATERIALS
Volume: 53
Number: 4
Publisher: REDAKCIA KOVOVE MATERIALY, Slovakia
Uncontrolled Keywords: thermally activated flow, activation area, composite model, subgrain boundaries, dislocations, recovery
Divisions: 11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences > Material Science > Physical Metallurgy
11 Department of Materials and Earth Sciences
Date Deposited: 25 Jan 2016 11:38
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