Solid state Si diffusion and joint formation involving aluminum brazing sheet

Feng Gao, Hui Zhao, Dusan P. Sekulic, Yiyu Qian, Larry Walker

Research output: Contribution to journalArticlepeer-review

38 Scopus citations


The paper provides information about the use of in situ determined diffusion coefficients of silicon for modeling of a brazed joint formation, i.e. formation of the equilibrium surface of a molten Al+xSi alloy at the onset of solidification in the joint. Diffusion coefficients of Si were determined (within both the joint and/or residue zone) to analyze its migration across the clad-core interface of an Al brazing sheet, including both the period prior to reaching brazing temperature range, and the peak brazing temperature range. Subsequently, diffusion coefficients were used to predict the joint formation during brazing. Migration of silicon is not uniform along the clad-core interface during brazing and depends, in addition to material characteristics and process parameters, on the vicinity of the joint zone. It is argued that, due to these alterations, the joint formation modeling must be performed by using in situ determined diffusion coefficients. The diffusion coefficients determined directly from electron probe microanalysis (EPMA) scans at different locations along the cladding sheet and within the joint zone differ between each other and when compared to the literature data. This variation influences the outcome of the residue formation modeling; hence the joint formation modeling may be affected. The relation between these phenomena is briefly discussed and quantitative data regarding diffusion coefficients, and in particular an approach to utilization of these data in modeling of joint formation, are provided. Published by Elsevier Science B.V.

Original languageEnglish
Pages (from-to)228-235
Number of pages8
JournalMaterials Science and Engineering: A
Issue number1-2
StatePublished - Nov 25 2002

Bibliographical note

Funding Information:
National Science Foundation provided support through the NSF Grant DMI-9908319, monitored by Dr Delcie Durham. One of the authors (GF) would like to express his appreciation for the support provided by CRMS through a research assistantship. Portion of this work was supported by Assistant Secretary for Energy, Office of Transportation Technologies, as part of the High Temperature Materials Laboratory User Program, ORNL, managed by UT-Battelle, LLC, for the US DOE under contract # DE-AC05-00OR22725. Oak Ridge National Laboratory through the project # UA-90-015. An early version of this work was presented at the International Brazing and Soldering Conference in Yangzhong, China, November 2001.


  • Al-Si diffusion coefficient
  • Controlled atmosphere brazing
  • Electron probe microanalysis
  • Joint formation
  • Modeling

ASJC Scopus subject areas

  • General Materials Science
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering


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