Microstructure and flow stress of polycrystals and single crystals

Journal Article · Mon Mar 02 04:00:00 EST 1998 · Acta Materialia

DOI:https://doi.org/10.1016/S1359-6454(97)00365-0· OSTI ID:616404

Hansen, N; Huang, X ^[1]

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1. Risoe National Lab., Roskilde (Denmark). Materials Research Dept.

The relation between polycrystal deformation and single crystal deformation has been studied in this work. A pure aluminum polycrystal having an average grain size of 300 {micro}m has been strained in tension at room temperature. The flow stress has been determined at four different strains (0.05, 0.14, 0.22 and 0.34) and deformation microstructures have been characterized qualitatively and quantitatively by transmission electron microscopy. Improved experimental techniques have allowed large foil areas to be characterized and in total 89 grains have been examined. At the four strains examined a classification of the deformation microstructures into three different types has shown a correlation between the grain orientation and the type of deformation microstructure which develops during straining. The dislocation density has been calculated at each strain and by assuming that the shear stress is proportional to the square root of the dislocation density the shear stress-strain relationship has been derived for each of the three groups of grains showing different deformation microstructures. The stress-strain curves show a strain hardening behavior which depends on the orientation of the grain. The behavior of the grains embedded in the polycrystal is compared with the behavior of single crystals and the stress-strain curve of the polycrystal is estimated with good accuracy from single crystal data, which are weighted based on a quantitative texture analysis of the polycrystal.

• OSTI ID: 616404
• Journal Information: Acta Materialia, Journal Name: Acta Materialia Journal Issue: 5 Vol. 46; ISSN 1359-6454; ISSN ACMAFD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM
COMPARATIVE EVALUATIONS
DEFORMATION
FLOW STRESS
MICROSTRUCTURE
MONOCRYSTALS
POLYCRYSTALS
STRAIN HARDENING