Abstract
Y 2O 3-dispersed NiAl was produced by a powder-metallurgy process. By adding Y as an oxide dispersion (OD), problems with NiY x formation and internal oxidation were avoided. Short-term isothermal and cyclic-oxidation performance at 1200°-1500°C was compared to cast NiAl alloys with and without Zr. Results indicate that the Y 2O 3 addition was beneficial to scale adhesion and significantly modified the α-Al 2 O 3 scale microstructure, similar to a Zr alloy addition. However, at 1400 and 1500° C, neither the Y 2O 3 or Zr additions changed the scale-growth rate, eliminated the formation of voids at the metal-scale interface or prevented scale spallation. These similarities in performance suggest that similar mechanisms occur when the reactive element is added as either an OD or an alloy addition.
| Original language | English |
|---|---|
| Pages (from-to) | 273-292 |
| Number of pages | 20 |
| Journal | Oxidation of Metals |
| Volume | 61 |
| Issue number | 3-4 |
| DOIs | |
| State | Published - Apr 2004 |
Funding
The authors are very grateful to the Electric Power Research Institute for providing financial support, Dr. R. Mason and Prof. N. J. Grant for assistance with powder blending, Homogeneous Metals, Clayville, NY for the NiAl powder, and Dr. J. D. Whittenberger and Dr. J. Doychak at NASA Lewis for extruding the OD NiAl alloy and providing the NiAl ingots. P. F. Tortorelli and I. G. Wright provided useful comments on the manuscript at ORNL.
Keywords
- Al o scale
- High-temperature oxidation
- Nickel aluminides
- Oxide dispersion
- Reactive element