Abstract
The bicrystals of both an Fe-36% Ni alloy and Incoloy alloy 909 were oxidized at 1200 and 1250 K in air respectively with a tensile stress of 2.5, 4.9, or 14.7 MPa. The thickness of external scale, intergranular subscale and intragranular subscale all exhibited linear relationships with the square root of oxidation time, indicating that oxidation followed parabolic law. In oxidized Fe-36% Ni bicrystals, leading cellular oxide nodules formed in intragranular subscale and a tensile stress promoted intergranular oxidation and the formation of cavities at the grain boundary. In oxidized Incoloy alloy 909 bicrystals, intergranular subscale only slightly led the internal subscale. However, intergranular oxidation was obvious in equiaxed specimens of this alloy. The external scale was stratified in Fe-36% Ni alloy, but it exhibited cellular or pocket-like structure in Incoloy alloy 909. The latter alloy possessed a much better resistance to oxidation than the Fe-36% Ni alloy.
| Original language | English |
|---|---|
| Pages (from-to) | 57-64 |
| Number of pages | 8 |
| Journal | Materials at High Temperatures |
| Volume | 18 |
| Issue number | 1 |
| DOIs | |
| State | Published - 2001 |
| Externally published | Yes |
Keywords
- Bicrystal
- Fe-36% Ni alloy
- High-temperature oxidation
- Incoloy alloy 909
- Oxidation kinetics
- Scale formation
- Tensile stress