Plasticity and interfacial dislocation mechanisms in epitaxial and polycrystalline Al films constrained by substrates

G. Dehm, T. Wagner, T. J. Balk, E. Arzt, B. J. Inkson

Research output: Contribution to journalArticlepeer-review

49 Scopus citations

Abstract

Stresses in epitaxial and textured Al films were determined by substrate-curvature measurements. It is found that in both cases the flow stresses increase with the decrease of film thickness. The flow stress in the epitaxial Al films is in agreement with a dislocation-based model, while the same model strongly underestimates the flow stress of textured Al films. In-situ transmission electron microscopy studies indicate that dislocations channeling through epitaxial Al films on single-crystalline (0001) α-Al2O3 substrates frequently deposit dislocation segments adjacent to the interface. Furthermore, the Al/α-Al2O3 interface can act as a dislocation source. In this case, the interface is between two crystalline lattices. In contrast, the interface of textured Al films on oxidized silicon substrates is between the crystalline Al and the amorphous SiOx interlayer. It is speculated that the different nature of the interfaces changes the dislocation mechanism and thus influences the flow stress.

Original languageEnglish
Pages (from-to)113-117
Number of pages5
JournalJournal of Materials Science and Technology
Volume18
Issue number2
StatePublished - Mar 2002

Keywords

  • Dislocation
  • Interface
  • Plasticity
  • Thin film

ASJC Scopus subject areas

  • Ceramics and Composites
  • Mechanics of Materials
  • Mechanical Engineering
  • Polymers and Plastics
  • Metals and Alloys
  • Materials Chemistry

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