|About this Abstract
||2018 TMS Annual Meeting & Exhibition
||Refractory Metals 2018
||Oxidation Resistance of W Substituted Mo-Si-B
||Gaoyuan Ouyang, Pratik K Ray, Tuba Karahan, Matthew J Kramer, Mufit Akinc
|On-Site Speaker (Planned)
Mo-Si-B alloys are promising materials for next generation turbine blades that require higher operating temperatures. Its metal phase offers excellent creep resistance and fracture toughness, and its intermetallic T2 phase offers exceptional oxidation resistance. W substitution in Mo-Si-B resulted in the destabilization of the deleterious A15 phase, and altered the oxidation behavior. It was found that the oxide scale coverage of the transient oxidation stage greatly depended on the microstructure size scale and the metal oxide removal rate. Uniform scale coverage was achieved with alloys having finer microstructure size scales produced by arc melting compared to the ones having larger grains produced by sintering. Unlike (MoO<SUB>3</SUB>)<SUB>3</SUB>, which volatilizes above 700°C, significant volatilization of (WO<SUB>3</SUB>)<SUB>3</SUB> does not happen until 1300°C. The presence of (WO<SUB>3</SUB>)<SUB>3</SUB> on the surface adversely affected the oxidation resistance at 1100°C. At 1400°C, (WO<SUB>3</SUB>)<SUB>3</SUB> was removed, and adequate scale coverage was obtained for improved oxidation resistance.
||Planned: Supplemental Proceedings volume