Plastic deformation of polycrystals of Co3(Al,W) with the L12 structure

Norihiko L. Okamoto, Takashi Oohashi, Hiroki Adachi, Kyosuke Kishida, Haruyuki Inui, Patrick Veyssiere

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80 Citations (Scopus)


The plastic behaviour of Co3(Al,W) polycrystals with the L1 2 structure has been investigated in compression from 77 to 1273 K. The yield stress exhibits a rapid decrease at low temperatures (up to room temperature) followed by a plateau (up to 950 K), then it increases anomalously with temperature in a narrow temperature range between 950 and 1100 K, followed again by a rapid decrease at high temperatures. Slip is observed to occur exclusively on {111} planes at all temperatures investigated. The rapid decrease in yield stress observed at low temperatures is ascribed to a thermal component of solid-solution hardening that occurs during the motion of APB-coupled dislocations whose core adopts a planar, glissile structure. The anomalous increase in yield stress is consistent with the thermally activated cross-slip of APB-coupled dislocations from (111) to (010), as for many other L1 2 compounds. Similarities and differences in the deformation behaviour and operating mechanisms among Co3(Al,W) and other L1 2 compounds, such as Ni3Al and Co3Ti, are discussed.

Original languageEnglish
Pages (from-to)3667-3684
Number of pages18
JournalPhilosophical Magazine
Issue number28
Publication statusPublished - 2011 Oct


  • Co-base superalloys
  • compression deformation behaviour
  • dislocation
  • intermetallic compound
  • transmission electron microscopy


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