Investigation of the microstructural evolution during large strain cold working of metals by means of synchrotron radiation - A comparative overview

M. Zehetbauer, E. Schafler, T. Ungár, I. Kopacz, S. Bernstorff

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

Dislocation densities, arrangements and long range internal stresses in cold rolled polycrystalline Cu, Ni, and Al, as well as in cold torsioned Fe, were determined by X-ray diffraction profile analysis using synchrotron radiation. At different deformation degrees, scanning measurements across single grains with a focal spot of less than 50 μn were carried out, in order to inform on the features of the deformation induced substructure. At small deformations including stage III, the dislocation densities and internal stresses are uniform within single grains while at higher deformations in stages IV and V, the dislocation densities and long range internal stresses exhibit opposite fluctuations. In stage IV these fluctuations correspond to the formation of polarized tilt walls (PTW's) from polarized dipole walls (PDW's). In contrast to the PDW's, the PTW's cause a much higher misorientation in between adjacent lattice areas. This transformation, which is the main element of the progressing fragmentation process during large strain deformation, occurs in all metals studied regardless of dislocation mobility and/or lattice type. Approaching higher strains in stage V, however, these parameters gain some importance especially when the deformation occurs in an iterative way. If the mobility is high, marked static recovery takes place between the single deformation passes, which results in decreases of both dislocation density and local internal stress, and no formation of PTW's is observed.

Original languageEnglish
Pages (from-to)41-47
Number of pages7
JournalJournal of Engineering Materials and Technology, Transactions of the ASME
Volume124
Issue number1
DOIs
Publication statusPublished - Jan 2002

Fingerprint

cold working
Cold working
Microstructural evolution
Synchrotron radiation
synchrotron radiation
Metals
residual stress
Residual stresses
metals
dipoles
substructures
misalignment
X ray diffraction analysis
fragmentation
recovery
Scanning
Recovery
scanning
causes
profiles

ASJC Scopus subject areas

  • Mechanical Engineering
  • Materials Science(all)

Cite this

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