Formation of β'-related composite precipitates in relation to enhanced thermal stability of Sc-alloyed Al-Mg-Si alloys
| Autor: | Yutang Liu, J.H. Chen, Sidong Chen, Y.X. Lai, Z.Q. Chen, Peng Gao |
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| Rok vydání: | 2021 |
| Předmět: |
Materials science
Mechanical Engineering Composite number Alloy Metals and Alloys 02 engineering and technology engineering.material 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences Crystallography Mechanics of Materials Scanning transmission electron microscopy Materials Chemistry engineering Thermal stability 0210 nano-technology Strong binding |
| Zdroj: | Journal of Alloys and Compounds. 885:160942 |
| ISSN: | 0925-8388 |
| Popis: | The Al-Mg-Si alloys added with trace Sc demonstrates an improved thermal stability, as compared with that without Sc-addition. But the microstructural origin of the enhanced property is unclear. In the present study, the precipitates formed in an Al-Mg-Si-Sc alloy were studied in detail by atomic-resolution scanning transmission electron microscopy. It is shown that the dominant precipitates formed at the peak-aging condition are the disordered β" precipitates consisting of Sc-free β" sub-units and Sc-containing disordered regions, rather than the well-ordered β". Upon further aging, these disordered β" precipitates will evolve to β"/β'/B′/U2 composite precipitates. The formation of the composite precipitates is probably associated with the strong binding between Sc and Si atoms, and with the non-preference for Sc atoms to occupy the atomic sites of the β"-structure. Our study reveals the following: It is the formation of stabilized β"-related composite precipitates that enhances the thermal stability of the Sc-added Al-Mg-Si alloy. |
| Databáze: | OpenAIRE |
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