New ordered phase in the quasi-binary UAl3-USi3 system

Gennady Rafailov, Isaac Dahan, Louisa Meshi

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


The industrial importance of the U-Al-Si system stems from the fact that during processing the Al-based alloy (containing Si as impurity), used for the cladding of U (fuel in nuclear reactors), undergoes heat treatment which stimulates diffusion between the fuel and the cladding. One of the possible ways to represent the ternary U-Al-Si phase diagram is the construction of an UAl3-USi3 quasi-binary phase diagram. On the one hand, since the UAl3 and USi3 phases are isostructural, an isomorphous phase diagram is expected; on the other hand, some researchers observed a miscibility gap at lower temperatures. During our study of the UAl3-USi3 quasi-binary phase diagram, a new stable U(Al x ,Si1-x )3 phase was identified. The structure of this phase was determined, using a combination of electron crystallography and powder X-ray diffraction methods, as tetragonal [I4/mmm (No.139) space group], with lattice parameters a = b = 8.347(1), c = 16.808(96)Å. Its unit cell has 64 atoms and it can be described as an ordered variant of the U(Al,Si)3 solid solution. A Bärnighausen tree was constructed using the original U(Al,Si)3 structure as an aristotype.

Original languageEnglish
Pages (from-to)580-585
Number of pages6
JournalActa Crystallographica Section B: Structural Science, Crystal Engineering and Materials
Issue number3
StatePublished - 1 Jan 2014


  • electron crystallography
  • ordering
  • powder X-ray diffraction
  • structure solution

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Metals and Alloys
  • Materials Chemistry


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