|About this Abstract
||Materials Science & Technology 2011
||MS&T'11 Poster Session
||154 Comparison of Oxidation Behavior of Nb-20Si-20Cr-5Hf and Nb-20Si-20Cr-5Al Alloys
||Brenda Arellano, Amanda Gutierrez, Alma Vasquez, David Alvarez, Shailendra K Varma
|On-Site Speaker (Planned)
The oxidation behavior of two alloys from the Nb-Si-Cr system containing hafnium and aluminum has been investigated under isothermal conditions. Nb-20Si-20Cr-5Hf and Nb-20Cr-20Si-5Al (in atomic pct) were oxidized in air in a temperature range from 700-1400°C. The as-cast alloys and oxidation products were characterized using SEM, EDS, x-ray mapping, and XRD. Catastrophic oxidation occurred at 700°C for 5Al alloy indicating pesting behavior compared to the 5Hf at 700°C which showed excellent oxidation behavior. Internal oxidation was detected from 1100-1400°C in the 5Al alloy. Partial pesting was observed for 5Hf alloy at 800°C. A weight gain per unit area as a function of oxidation temperature was used to determine the oxidation kinetics. In addition, the microstructures were compared in the as-cast condition and after oxidation for the two alloys at the specified temperature range.