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Influence of the Small Sc and Zr Additions on the As-Cast Microstructure of Al–Mg–Si Alloys with Excess Silicon
| Content Provider | MDPI |
|---|---|
| Author | Aryshenskii, Evgenii Lapshov, Maksim Hirsch, Jurgen Konovalov, Sergey Bazhenov, Viacheslav Drits, Alexander Zaitsev, Denis |
| Copyright Year | 2021 |
| Description | This research is devoted to the study effects of complex alloying of Al-0.3 wt. % Mg-1 wt. % Si and Al-0.5 wt. % Mg-1.3 wt. % Si alloys by small additions of Sc and Zr on the microstructure in the as-cast condition. The effect of small additions of these elements on the microhardness, electrical conductivity, grain size and phase composition of the indicated alloy systems was studied. The methods of optical and electron microscopy were used for the study. Moreover, the phase composition was calculated using the Thermo-Calc software package. The study showed a strong effect of the chemical composition of investigated alloys on the size of the grains, which, with a certain combination of additives, can decrease several times. Grain refinement occurs both due to supercooling and formation of primary $Al_{3}$Sc particles in the liquid phase. Alloys based on Al-0.5 wt. % Mg-1.3 wt. % Si are more prone to the formation of this phase since a lower concentration of Sc is required for it to occur. In addition, more silicon interacts with other elements. At the same time, Al-0.3 wt. % Mg-1 wt. % Si requires lower temperature for complete dissolution of $Mg_{2}$Si, which can contribute to more efficient heat treatment, which includes reducing the number of steps. TEM data show that during ingot cooling $(AlSi)_{3}$ScZr dispersoid precipitates. This dispersoid could precipitate as coherent and semi-coherent particles with $L1_{2}$ structure as well as needle-shaped particles. The precipitation of coherent and semi-coherent particles during cooling of the ingot indicates that they can be obtained during subsequent multistage heat treatment. In addition, in the Al0.5Mg1.3Si0.3Sc alloy, metastable β″ $(Mg_{5}Si_{6}$) are precipitated. |
| Starting Page | 1797 |
| e-ISSN | 20754701 |
| DOI | 10.3390/met11111797 |
| Journal | Metals |
| Issue Number | 11 |
| Volume Number | 11 |
| Language | English |
| Publisher | MDPI |
| Publisher Date | 2021-11-08 |
| Access Restriction | Open |
| Subject Keyword | Metals Manufacturing Engineering Aluminum Alloys Phase Composition Casting Sc and Zr Small Addition Grain Refinement Dispersoid |
| Content Type | Text |
| Resource Type | Article |
