Metallurgical and Materials Transactions A

, Volume 25, Issue 11, pp 2518–2523 | Cite as

Nonequilibrium solidification of undercooled melt of Ag-Cu alloy entrained in the primary phase

  • O. P. Pandey
  • N. S. Mishra
  • C. Ramachandra
  • S. Lele
  • S. N. Ojha
Solidification

Abstract

The solidification structure of undercooled melt of Ag-Cu alloy, entrained in its primary Cu-rich phase, has been investigated. The undercooling procedure consisted of equilibration of a Cu-13 pct Ag alloy in the two-phase liquid-solid region, followed by repeated thermal cycling of the liquid. Slow cooling of the sample in the present work established the ability to undercool the melt up to 70 K below the eutectic temperature of this alloy. The microstructure of the undercooled alloy indicated a complete absence of eutectic reaction on subsequent quenching of the melt directly from the equilibration temperature. The compositional analysis of the constituent phases by electron probe microanalysis (EPMA) technique provided evidence for the massive diffusionless solidification of the undercooled liquid. The X-ray diffraction study and electron microscopic examination indicated evidence for the spinodal transformation of the metastable solid solution phase. The composition of the phases formed on decomposition matched well with the calculated coherent spinodal boundaries in this system. The evolution of the metastable microstructure in the mushy-state quenching process of this alloy is discussed.

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Copyright information

© The Minerals, Metals and Materials Society, and ASM International 1994

Authors and Affiliations

  • O. P. Pandey
    • 1
  • N. S. Mishra
    • 2
  • C. Ramachandra
    • 3
  • S. Lele
    • 3
  • S. N. Ojha
    • 3
  1. 1.Department of Materials ScienceThapar Insitute of Engineering and TechnologyPatiala-147001India
  2. 2.Research and Development CenterSAILRanchi-834002India
  3. 3.Center for Advanced Study, Department of Metallurgical EngineeringBanaras Hindu UniversityVaranasi-221005India

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