Precipitate Evolution and Creep Behavior of a W-Free Co-based Superalloy
| Autor: | James Coakley, Qinyuan Liu, David N. Seidman, David C. Dunand |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
010302 applied physics
Materials science Metallurgy Neutron diffraction Alloy Metals and Alloys chemistry.chemical_element 02 engineering and technology Tungsten engineering.material 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences Indentation hardness Superalloy chemistry Creep Mechanics of Materials 0103 physical sciences Volume fraction engineering Crystallite 0210 nano-technology |
| Zdroj: | Metallurgical and Materials Transactions A. 47:6090-6096 |
| ISSN: | 1543-1940 1073-5623 |
| Popis: | The morphological and temporal evolution of \(\gamma ^{\prime }\) (L1\(_2\))-precipitates is studied in a polycrystalline Co-based superalloy (Co-30Ni-9.9Al-5.1Mo-1.9Nb at. pct) free of tungsten, aged at 1173 K (900 °C). Over a \(1000\,{{\rm{hours}}}\) heat-treatment, the \(\gamma ^{\prime }\) morphology evolves due to precipitate coalescence. The particles grow in size and the volume fraction decreases, while there is no significant change in the microhardness value. Compressional creep tests at 1123 K (850 °C) on a specimen aged at 1173 K (900 °C) demonstrate that the creep resistance is comparable to the original, W-containing, higher-density Co-based superalloy (Co-9Al-9.8W at. pct). This represents the first creep study of the Co-Al-Mo-Nb-based superalloy system. The W-free alloy exhibits directional coarsening of the \(\gamma ^{\prime }\) precipitates in the direction perpendicular to the applied compressive stress, which indicates a positive misfit. This is consistent with neutron diffraction results. |
| Databáze: | OpenAIRE |
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