Thermal oxidation characteristics of Fe (CoCrMnNi) medium and high-entropy alloys
| Autor: | Unhae Lee, Nokeun Park, Maya Putri Agustianingrum, Fahamsyah H. Latief |
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| Rok vydání: | 2020 |
| Předmět: |
010302 applied physics
Thermal oxidation Materials science Kirkendall effect Mechanical Engineering Diffusion High entropy alloys Alloy Metals and Alloys Oxide 02 engineering and technology General Chemistry Activation energy engineering.material 021001 nanoscience & nanotechnology 01 natural sciences chemistry.chemical_compound Chemical engineering chemistry Mechanics of Materials 0103 physical sciences Materials Chemistry engineering 0210 nano-technology Internal oxidation |
| Zdroj: | Intermetallics. 120:106757 |
| ISSN: | 0966-9795 |
| Popis: | The thermal oxidation behavior of Fex(CoCrMnNi)100-x high-entropy alloys (x = 20 and 40 at.%) and medium-entropy alloy (x = 60 at.%) at temperatures ranging from 900 °C to 1100 °C under air atmosphere was investigated. The oxidation kinetics of the alloys followed the parabolic law, indicated by the increase of oxidation rate constants with increasing Fe content and temperature. The addition of Fe content lowered the configurational entropy and activation energy of the alloys, supporting the acceleration of metal atoms diffusion. Furthermore, the oxide scales formed on the surface were strongly dependent on the alloy composition. In general, a Cr2O3 inner layer, spinels (NiCr2O4 and CoMn2O4) as intermediate layers, and the outer layers of Fe3O4 and Mn3O4 were formed after oxidation at 900 °C in all alloys. On the other hand, severe internal oxidation and pores were observed in the alloy containing 60 at.% of Fe after oxidation at 1100 °C. In addition, the pores were formed due to the Kirkendall effect, acting as diffusion path and reaction place which may facilitate the oxidation process. |
| Databáze: | OpenAIRE |
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