| About this Abstract |
| Meeting |
Materials Science & Technology 2020
|
| Symposium
|
High Temperature Corrosion and Degradation of Structural Materials
|
| Presentation Title |
Environmental Resistance and Microstructure Design in Mo-Si-B Alloys |
| Author(s) |
John H. Perepezko |
| On-Site Speaker (Planned) |
John H. Perepezko |
| Abstract Scope |
The multiphase microstructures in the Mo-Si-B system based upon the Mo5SiB2 (T2) phase with Mo and the Mo3Si phases allow for superior creep strength, in-situ toughening and offer some oxidation resistance. Selected alloying can also be used to develop alternative multiphase microstructures. Since the alloy compositions that exhibit the lowest oxidation rate will most likely not yield optimum mechanical properties, it is important to develop robust and compatible aenvironmental resistant coatings. An effective strategy to address this challenge is based upon a pack cementation kinetic biasing. During oxidation of the (Si+B)-pack alloys, the initial MoSi2 outer layer is consumed by formation of the Mo5Si3 (T1) phase and the underlying T2 and/or boride phase diffusion barrier layer. Any damage to the T1 layer can be recovered from the T2 + MoB layer as a self-healing characteristic. The coating strategy is also applicable to other refractory metals and ceramics. |