Grain boundary character dependence on nucleation of discontinuous precipitates in Cu-Ti alloys

Satoshi Semboshi, Mitsutaka Sato, Yasuyuki Kaneno, Akihiro Iwase, Takayuki Takasugi

Research output: Contribution to journalArticlepeer-review

22 Citations (Scopus)


The dependence of the grain boundary character distribution for a Cu-4 at. % Ti polycrystal alloy (average grain size: 100 μm) on the nucleation of cellular discontinuous precipitates was systematically investigated. In an alloy over-aged at 723 K, cellular discontinuous precipitates consisted of a terminal Cu solid solution and a stable β-Cu4Ti lamellae nucleated at grain boundaries. Electron backscatter diffraction analysis revealed that the discontinuous precipitation reaction preferentially occurred at random grain boundaries with a Σ value of more than 21 according to the coincidence site lattice theory. On the other hand, few cellular discontinuous precipitates nucleated at low-angle and low-Σ boundaries, particularly twin (Σ 3) boundaries. These findings suggest that the nucleation of discontinuous precipitates is closely correlated with grain boundary character and structure, and hence energy and/or diffusibility. It should therefore be possible to suppress the discontinuous precipitation reaction through control of the alloy's grain boundary energy, by means of texture control and third elemental addition.

Original languageEnglish
Article number415
Issue number4
Publication statusPublished - 2017 Apr 15


  • Aging
  • Cu alloy
  • Discontinuous precipitation
  • Electron backscattering diffraction
  • Grain boundary
  • Misorientation
  • Value
  • Σ


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