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Journal of Materials Science

, Volume 18, Issue 10, pp 3011–3022 | Cite as

Electron microscopic investigations on a melt-quenched Al-Rh alloy

  • Zariff A. Chaudhury
  • C. Suryanarayana
Papers

Abstract

An Al-2 wt% Rh alloy was subjected to rapid quenching from the molten state and transmission electron microscopy and diffraction techniques were extensively used to characterize the phases present. Melt quenching led to the formation of a homogeneous solid solution, indicating a substantial increase in solid solubility limit over the equilibrium value. Although stable up to about 640 K, the supersaturated solid solution decomposed at elevated temperatures to a mixture of aluminium solid solution and an intermediate phase, which has been identified to have a monoclinic structure witha=1.636 nm,b=0.805 nm,c=1.279 nm andΒ=107.77° with a stoichiometry corresponding to Al13Rh4. Although heterogeneous nucleation at grain boundaries was the predominant feature, the precipitate also formed as WidmanstÄtten platelets inside the grains. This phase has been shown to be an equilibrium phase. Very long annealing treatments at temperatures of 773 K resulted in the formation of an ordered phase. The long-range order was destroyed on heating to still higher temperatures. The equilibrium constitution of the alloy has been shown to be a mixture of Al13Rh4 and aluminium solid solution.

Keywords

Transmission Electron Microscopy Solid Solution Solid Solubility Annealing Treatment Intermediate Phase 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Chapman and Hall Ltd 1983

Authors and Affiliations

  • Zariff A. Chaudhury
    • 1
  • C. Suryanarayana
    • 1
  1. 1.Centre of Advanced Study in Metallurgy, Department of Metallurgical EngineeringBanaras Hindu UniversityVaranasiIndia

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