In-situ synchrotron X-ray micro-diffraction investigation of ultra-low-strain deformation microstructure in laminated Ti-Al composites

Tianbo Yu*, Yan Du, Guohua Fan*, Ruqing Xu, Rozaliya Barabash, Niels Hansen, Xiaoxu Huang, Yubin Zhang

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

An ultra-low-strain deformation microstructure was revealed for the first time non-destructively in the bulk interior of an annealed laminated Ti-Al composite—in the “fully recrystallized” Al layer—by a synchrotron-based micro-diffraction technique, namely differential aperture X-ray microscopy (DAXM), through real space mapping with a very high angular resolution (0.01°). This ultra-low-strain deformation microstructure was found to result from the thermal stress, induced during cooling after annealing, due to the different coefficients of thermal expansion for the Ti and Al layers. The annealed sample was further tensile deformed to a strain of 1.66% and followed by in situ DAXM and analyzed by various misorientation mapping methods. The results pointed to the important effects of the initial microstructure and the interface constraint, as well as the grain size and crystal orientation, on the plastic deformation. A gradient in dislocation density from the layer interface to the center was found in the Al layer of the annealed sample, and this gradient increased slightly during tensile deformation. The variation of the dislocation density was further discussed based on the activation and interaction of dislocations in grains of different sizes and orientations during plastic deformation. The findings of this study provided valuable insights in understanding the constraint effect of the laminated metal composite and the design of novel composite materials.
Original languageEnglish
JournalActa Materialia
Volume202
Pages (from-to)149-158
ISSN1359-6454
DOIs
Publication statusPublished - 2021

Bibliographical note

GA no. 788567

Keywords

  • Plastic deformation
  • Synchrotron diffraction
  • Laminated metal composite
  • Microstructure
  • Crystallographic orientation

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