Evaluation of Driving Force and Mobility for Diffusion Induced Grain Boundary Migration in Ni(Cu) System.

• Moriyama Miki

  Graduate Student, Tokyo Institute of Technology

• Kajihara Masanori

  Department of Materials Science and Engineering, Tokyo Institute of Technology

Abstract

The kinetics of diffusion induced grain boundary migration (DIGM) in the Ni(Cu) system was experimentally studied by Liu et al. using polycrystalline Cu/Ni/Cu diffusion couples annealed at 888 K for various times between 4.8×10² and 9.36×10⁴s. The notation Ni(Cu) means that Cu atoms diffuse into a pure Ni or binary Ni-Cu phase. Their experimental results have been quantitatively analyzed using the energy balance model proposed by Kajihara and Gust. The face-centered-cubic (f.c.c.) solution phase in the binary Ni-Cu system is assumed to be elastically isotropic. The molar Gibbs energy of the f.c.c. phase is expressed by a subregular solution model. The migration rate v of the moving grain boundary is described as a function of the reaction time t by the equation v=k(t/t₀)^m. Here, t₀ is unit time, 1 s. From these relationships, the effective driving force Δ^efG_m for DIGM has been calculated as a function of the reaction time. Although Δ^efG_m monotonically decreases with increasing reaction time from the maximum value of 184 J/mol to the minimum value of 8 J/mol, it is still large enough to drive the grain boundary migration against the curvature of the moving grain boundary even at late stages of the reaction. The mobility M of the moving grain boundary also monotonically decreases with increasing reaction time from 2×10^-17 m⁴/J s at 4.8×10²s to 2×10^-18 m⁴/J s at 9.36×10⁴s. However, considering the grain boundary energy contribution due to the curvature of the moving grain boundary, M is supposed to be almost constant during the reaction.

Journal

• ISIJ International

  ISIJ International 38 (1), 86-92, 1998

  The Iron and Steel Institute of Japan

Keywords

• diffusion induced grain boundary migration
• Ni-Cu system
• grain boundary migration
• grain boundary diffusion

Details

• CRID: 1390001206451354240
• NII Article ID: 10002458428
• NII Book ID: AA10680712
• DOI: 10.2355/isijinternational.38.86
• ISSN: 13475460
• ISSN: 09151559
• Web Site: http://www.jstage.jst.go.jp/article/isijinternational1989/38/1/38_1_86/_pdf
• Text Lang: en
• Data Source:
  • JaLC
  • Crossref
  • CiNii Articles
• Abstract License Flag: Disallowed