Abstract
The effect of microstructural refinement on the oxidation behavior of γ+ laves Ti-45Al-15Cr and γ+ σ Ti-40Al-27Nb was investigated. A fine, uniform γ+ laves microstructure in Ti-45Al-15Cr resulted in protective alumina scale formation over most of the sample surface at 800°C and 10000C in air. In contrast, the oxidation resistance of this same alloy was severely degraded by a coarse γ+ laves microstructure. The oxidation behavior of Ti-40Al-27Nb at 1200°C in air was poor. Refinement of the γ+ σ microstructure in this alloy was not effective in improving oxidation resistance. The mechanistic reasons for these effects, and the implications for improved oxidation resistance through microstructural refinement are discussed.
| Original language | English |
|---|---|
| Pages (from-to) | 635-653 |
| Number of pages | 19 |
| Journal | Materials and Manufacturing Processes |
| Volume | 11 |
| Issue number | 4 |
| DOIs | |
| State | Published - 1996 |
| Externally published | Yes |
Funding
The authors wish to thank S.P. Elder Randall, R.J. Hanrahan, Jr., J.C. Liu, and F. Ebrahimi for their helpful discussions of microstructure and oxidation in the Ti-Al-Nb system. The authors also wish to thank United Technologies ( h t tand Whitney) for supplying the arc-melted buttons of Ti-Al-Nb alloys. The Ti-Al-Nb work was performed at the University of Florida and supported by DARPA under grant # MDA 972-88-J-1006 and Ofice of Naval Research grant # NO00 1 4-88-J-1 100. The Ti-Al-Cr work was performed at NASA Lewis and supported under the HITEMP program. One author (MPB) wishes to acknowledge the support of a National Research Council PostDoctoral Fellowship. 9. Perkins, R. A,, K. T. Chiang, G. H. Meier, and R. A. Miller, "Effect of Alloying, Rapid Solidification, and Surface Kinetics on the High-temperature Environmental Resistance of Niobium" (Final Report Contract # F49620-86-C-0018 Air Force Office of Scientific Research, June 1989).