Phase relations in the Nb-Pd-Hf-Al system

A. Misra, Gautam Ghosh, G. B. Olson

Research output: Contribution to journalArticlepeer-review


In support of computational design of coherent aluminide strengthened Nb alloys, the phase equilibria in a series of six Nb-Pd-Hf-Al alloys were investigated using scanning electron microscopy (SEM) and x-ray diffraction (XRD). All alloys were heat treated at 1200°C for 200 h, while three alloys were also heat treated at 1500°C for 200 h. Three-phase equilibria and two-phase equilibria were observed in two alloys at both temperatures. Two more alloys also exhibited three-phase equilibria at 1200 °C, while one alloy exhibited two-phase equilibria at 1200 °C. A final alloy revealed four-phase equilibria at both temperatures, confirming the presence of a unique tie-tetrahedron in the Nb-Pd-Hf-Al system. Based on the characterization of phases by SEM and XRD, the Nb-Pd-Hf-Al partial phase diagram at 1200 °C has been constructed. Such phase diagrams provide the basis for designing precipitation-strengthened Nb-based superalloys.

Original languageEnglish (US)
Pages (from-to)507-514
Number of pages8
JournalJournal of Phase Equilibria and Diffusion
Issue number6
StatePublished - Nov 2004


  • Alloy 40Nb
  • Atomic Volume
  • Energy Dispersive Spectrometer
  • Phase Equilibrium
  • Phase Field

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Metals and Alloys
  • Materials Chemistry


Dive into the research topics of 'Phase relations in the Nb-Pd-Hf-Al system'. Together they form a unique fingerprint.

Cite this