Grain boundary sliding during ambient-temperature creep in hexagonal close-packed metals

Tetsuya Matsunaga, Tatsuya Kameyama, Shouji Ueda, Eiichi Sato

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

Even at ambient temperature or less, below their 0.2% proof stresses all hexagonal close-packed metals and alloys show creep behaviour because they have dislocation arrays lying on a single slip system with no tangled dislocation inside each grain. In this case, lattice dislocations move without obstacles and pile-up in front of a grain boundary. Then these dislocations must be accommodated at the grain boundary to continue creep deformation. Atomic force microscopy revealed the occurrence of grain boundary sliding (GBS) in the ambient-temperature creep region. Lattice rotation of 5 was observed near grain boundaries by electron backscatter diffraction pattern analyses. Because of an extra low apparent activation energy of 20 kJ/mol, conventional diffusion processes are not activated. To accommodate these piled-up dislocations without diffusion processes, lattice dislocations must be absorbed by grain boundaries through a slip-induced GBS mechanism.

Original languageEnglish
Pages (from-to)4041-4054
Number of pages14
JournalPhilosophical Magazine
Volume90
Issue number30
DOIs
Publication statusPublished - 2010 Oct 28

Keywords

  • ambient temperature creep
  • grain boundary sliding
  • hexagonal close-packed structure

ASJC Scopus subject areas

  • Condensed Matter Physics

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