Extended Solubility and Stability in Vapor Quenched Ni3al-X Intermetallics.

Abstract

ABSTRACTA series of fine-grain and amorphous Ni3Al-X alloys, where X is a solute of 1 to 45 at.% Hf, C or Hf+C in continuously graded compositions, was formed simultaneously into a 0.2 mm-thick disk by high-rate sputter co-deposition. The as-deposited Ni3Al-X alloys exhibited a disordered Ll2 structure and extended solid solubility limits beyond which amorphous phases were formed. Heat-treatment of the alloys at 900°C resulted in fine grain size of 0.5 to 1.5 μm. Ultra-fine dispersoids less than 500 Å in size were observed and they seemed resistant to coarsening.