Effect of Y2O3 Addition on Oxidation Behavior of W-Cr Alloys
Abstract
A study has been carried out on non-isothermal and cyclic oxidation behavior of the W1- x Cr x -3 wt pct Y2O3 ( x = 0.3 or 0.5) composite samples, and the results have been compared with those of binary W-Cr alloys. The microstructures of the sintered samples showed the presence of W-rich (β1) + Cr-rich (β2) regions and more or less uniformly distributed Y2O3 particles. Protection against high-temperature oxidation is possible due to the formation of a stable mixed oxide scale containing both Cr2WO6 and Y2W3O12 at the oxide-air interface. Melting of the eutectic composition of Y2W3O12 and WO3 leads to the formation of a liquid phase, which helps in closure of pores by sintering and viscoplastic flow of the oxide scale, thereby enhancing its resistance to spallation and further oxidation.
- Publication:
-
Metallurgical and Materials Transactions A
- Pub Date:
- December 2015
- DOI:
- 10.1007/s11661-015-3166-z
- Bibcode:
- 2015MMTA...46.5909T