Grain-boundary melting phase transition in the CuBi system

Sergiy Divinski, Maik Lohmann, Christian Herzig, Boris Straumal, Brigitte Baretzky, and Wolfgang Gust
Phys. Rev. B 71, 104104 – Published 22 March 2005

Abstract

Copper embrittlement by Bi atoms is a typical example of a severe detrimental phenomenon in materials science. It has recently been proposed that the strong Bi segregation in Cu can cause a liquidlike film at the grain boundaries (GBs), when the alloy is in the single-phase (solid solution) region of the equilibrium phase diagram [L.-S. Chang, E. Rabkin, B. B. Straumal, B. Baretzky, and W. Gust, Acta Mater. 47, 4041 (1999)]. However, a direct experimental confirmation of a liquidlike state of GBs in such a case is missing. If a liquidlike GB phase is indeed formed, the GB diffusivity should dramatically be enhanced. Radiotracer GB diffusion of Cu64 and Bi207 radioisotopes were measured in a set of well-characterized CuBi alloys in the single-phase (solid solution) region of the equilibrium phase diagram as well as in the two-phase (solid+liquid) region. An abrupt increase of the GB diffusivities of both Cu and Bi by about two orders of magnitude was observed at certain Bi contents which are unequivocally in the single-phase region and are definitely less than that associated with the bulk solidus concentration. This critical Bi concentration was the same for self- and solute GB diffusion. With further increase of the Bi content and after exceeding the bulk solidus concentration, only marginal changes in the diffusivities of Cu as well as Bi were observed. The present results convincingly showed the occurrence of the premelting phase transition in GBs of the CuBi system.

  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
  • Received 14 October 2004

DOI:https://doi.org/10.1103/PhysRevB.71.104104

©2005 American Physical Society

Authors & Affiliations

Sergiy Divinski*, Maik Lohmann, and Christian Herzig

  • Institute for Materials Physics, University of Münster, Wilhelm-Klemm-Strasse 10, D-48149 Münster, Germany

Boris Straumal, Brigitte Baretzky, and Wolfgang Gust

  • Max Planck Institute for Metals Research, Heisenbergstrasse 3, D-70569 Stuttgart, Germany

  • *Electronic address: divin@uni-muenster.de
  • Also at Institute of Solid State Physics, Russian Academy of Sciences, 142432 Chernogolovka, Moscow District, Russia.

Article Text (Subscription Required)

Click to Expand

References (Subscription Required)

Click to Expand
Issue

Vol. 71, Iss. 10 — 1 March 2005

Reuse & Permissions
Access Options

Authorization Required


×
×

Images

×

Sign up to receive regular email alerts from Physical Review B

Log In

Cancel
×

Search


Article Lookup

Paste a citation or DOI

Enter a citation
×