Observations of Grain-Boundary Sliding and Surface Topography in an 8090 Al Alloy after Uniaxial and Biaxial Superplastic Deformation

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

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Author(s)

Detail(s)

Original languageEnglish
Pages (from-to)53-64
Journal / PublicationMetallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
Volume30
Issue number1
Publication statusPublished - Jan 1999
Externally publishedYes

Abstract

The surface topography of an 8090 aluminum alloy was studied after uniaxial or biaxial superplastic deformation, with particular reference to grain-boundary sliding (GBS) offsets, grain rotation angles, formation of striated bands (SBs) or fibers, cavity distribution, and cavity formation mechanisms. Additionally, the contribution of GBS or grain separation to the overall strain was evaluated. Striated bands were observed and are thought to be the newly exposed faces of the grains inclined to the specimen's surface. They were formed by sliding of grains upward and downward relative to the specimen surface. Grooves and crests inside SBs were formed from the relative motion of grain-boundary defects. Fibers were observed and are thought to be the further development of the SBs resulting from the formation of elongated cavities and grain separation. More cavitation was found in equibiaxially strained regions than in other regions subjected to approximately equivalent levels of strain. About 50 pet of the total strain was contributed by GBS in the uniaxial tensile-loaded specimens, as compared to about 30 pct in the biaxial-strained specimens. The effects of grain separation, grain rotation, and secondary GBS may be the reasons for the reduction of the observed strain contribution from GBS in biaxially strained specimens.

Research Area(s)

  • Cavitation, Material Transaction, Uniaxial Tension, Marker Line, Cavity Growth

Citation Format(s)

Observations of Grain-Boundary Sliding and Surface Topography in an 8090 Al Alloy after Uniaxial and Biaxial Superplastic Deformation. / CHEN, T.R.; HUANG, J.C.
In: Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science, Vol. 30, No. 1, 01.1999, p. 53-64.

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review