Ir-Hf-Zr ternary refractory superalloys for ultra-high temperatures - Phase and microstructural constitution

J. B. Sha, Y. Yamabe-Mitarai

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

A phase and microstructural evaluation of Ir-Hf-Zr ternary alloys with a composition below 30 mol% (Hf + Zr) was conducted by microstructural observation using scanning electron microscopy (SEM), composition analysis using electron probe microscopy analysis (EPMA), and phase identification using X-ray diffraction analysis (XRD). Partial isothermal sections of the Ir-Hf-Zr ternary system close to the Ir corner at 1800 C and 2000 C were determined. Research revealed that the f.c.c. and L12-Ir3(Hf, Zr) two-phase regions, which are shown in the Ir-Hf and Ir-Zr binary systems, were connected from the Ir-Hf side to Ir-Zr side in the Ir-Hf-Zr ternary system at Hf + Zr contents of less than 25 mol%. The L12-Ir3Hf and L1 2-Ir3Zr phases were fully soluble with each other. An Ir3(Hf, Zr)/Ir(Hf, Zr) two-phase structure was found in the Ir-15Hf-15Zr alloy with the Hf + Zr contents of 30 mol%. The potential of the Ir-Hf-Zr ternary alloys as ultra-high-temperature structural materials is discussed from the viewpoints of the microstructure and the lattice misfit between the f.c.c. and the L12 phases.

Original languageEnglish
Pages (from-to)1-9
Number of pages9
JournalIntermetallics
Volume41
DOIs
Publication statusPublished - 2013 May 20
Externally publishedYes

Keywords

  • A. Multiphase intermetallics
  • B. Phase diagrams
  • C. Heat treatment
  • D. Microstructure

ASJC Scopus subject areas

  • Chemistry(all)
  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry

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