Microstructure and Hardness Evolution of Al8Zn7Ni3Mg Alloy after Casting at very Different Cooling Rates
In this study, we combined both a high strength Al-8%Zn-3%Mg aluminum matrix and a reinforcing contribution of Al<sub>3</sub>Ni intermetallics in Al8Zn7Ni3Mg hypereutectic alloy with a tuned microstructure via a variation of cooling rates from 0.1 K/s to 2.3 × 10<sup>5</sup>...
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MDPI AG
2020-06-01
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| Online Access: | https://www.mdpi.com/2075-4701/10/6/762 |
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| author | Pavel Shurkin Torgom Akopyan Nataliya Korotkova Alexey Prosviryakov Andrey Bazlov Alexander Komissarov Dmitry Moskovskikh |
| author_facet | Pavel Shurkin Torgom Akopyan Nataliya Korotkova Alexey Prosviryakov Andrey Bazlov Alexander Komissarov Dmitry Moskovskikh |
| author_sort | Pavel Shurkin |
| collection | DOAJ |
| description | In this study, we combined both a high strength Al-8%Zn-3%Mg aluminum matrix and a reinforcing contribution of Al<sub>3</sub>Ni intermetallics in Al8Zn7Ni3Mg hypereutectic alloy with a tuned microstructure via a variation of cooling rates from 0.1 K/s to 2.3 × 10<sup>5</sup> K/s. Using the Thermo-Calc software, we analyzed the effect of nickel content on the phase equilibria during solidification and found out that 7%Ni provides a formation of equal fractions of primary (6.5 vol.%) and eutectic (6.3 vol.%) crystals of the Al<sub>3</sub>Ni phase. Using microstructural analysis, a refinement of intermetallics with an increase in cooling rate was observed. It is remarkable that the structure after solidification at ~10<sup>3</sup> K/s across 1 mm flake casting consists of a quasi-eutectic with 1.5 μm Al<sub>3</sub>Ni fibers, while an increase in the cooling rate to ~10<sup>5</sup> K/s after melt spinning leads to the formation of 50 nm equiaxed Al<sub>3</sub>Ni particles. Under these conditions, the alloy showed an aging response at 200 °C, resulting in hardness of 200 HV and 220 HV, respectively. After 470 °C annealing, the fibers in the 1 mm sample evolved to needles. However, in melt-spun ribbons, the particles were kept globular and small-sized. Overall, the results may greatly contribute to the development of new eutectic type composites for rapid solidification methods. |
| first_indexed | 2024-03-10T19:19:13Z |
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| id | doaj.art-c2393abb828445c5a828f0e5e07bc3de |
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| language | English |
| last_indexed | 2024-03-10T19:19:13Z |
| publishDate | 2020-06-01 |
| publisher | MDPI AG |
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| series | Metals |
| spelling | doaj.art-c2393abb828445c5a828f0e5e07bc3de2023-11-20T03:08:12ZengMDPI AGMetals2075-47012020-06-0110676210.3390/met10060762Microstructure and Hardness Evolution of Al8Zn7Ni3Mg Alloy after Casting at very Different Cooling RatesPavel Shurkin0Torgom Akopyan1Nataliya Korotkova2Alexey Prosviryakov3Andrey Bazlov4Alexander Komissarov5Dmitry Moskovskikh6Department of Metal Forming, National University of Science and Technology MISiS, Leninsky Ave. 4, 119049 Moscow, RussiaDepartment of Metal Forming, National University of Science and Technology MISiS, Leninsky Ave. 4, 119049 Moscow, RussiaDepartment of Metal Forming, National University of Science and Technology MISiS, Leninsky Ave. 4, 119049 Moscow, RussiaDepartment of Physical Metallurgy of Non-Ferrous Metals, National University of Science and Technology MISiS, Leninsky Ave. 4, 119049 Moscow, RussiaDepartment of Physical Metallurgy of Non-Ferrous Metals, National University of Science and Technology MISiS, Leninsky Ave. 4, 119049 Moscow, RussiaLaboratory of Hybrid Nanostructured Materials, National University of Science and Technology MISiS, Leninsky Ave. 4, 119049 Moscow, RussiaCentre of Functional Nanoceramics, National University of Science and Technology MISiS, Leninsky Ave. 4, 119049 Moscow, RussiaIn this study, we combined both a high strength Al-8%Zn-3%Mg aluminum matrix and a reinforcing contribution of Al<sub>3</sub>Ni intermetallics in Al8Zn7Ni3Mg hypereutectic alloy with a tuned microstructure via a variation of cooling rates from 0.1 K/s to 2.3 × 10<sup>5</sup> K/s. Using the Thermo-Calc software, we analyzed the effect of nickel content on the phase equilibria during solidification and found out that 7%Ni provides a formation of equal fractions of primary (6.5 vol.%) and eutectic (6.3 vol.%) crystals of the Al<sub>3</sub>Ni phase. Using microstructural analysis, a refinement of intermetallics with an increase in cooling rate was observed. It is remarkable that the structure after solidification at ~10<sup>3</sup> K/s across 1 mm flake casting consists of a quasi-eutectic with 1.5 μm Al<sub>3</sub>Ni fibers, while an increase in the cooling rate to ~10<sup>5</sup> K/s after melt spinning leads to the formation of 50 nm equiaxed Al<sub>3</sub>Ni particles. Under these conditions, the alloy showed an aging response at 200 °C, resulting in hardness of 200 HV and 220 HV, respectively. After 470 °C annealing, the fibers in the 1 mm sample evolved to needles. However, in melt-spun ribbons, the particles were kept globular and small-sized. Overall, the results may greatly contribute to the development of new eutectic type composites for rapid solidification methods.https://www.mdpi.com/2075-4701/10/6/762composite materialshypereutectic aluminum alloysAl-Zn-Mg alloysrapid solidificationeutecticCALPHAD |
| spellingShingle | Pavel Shurkin Torgom Akopyan Nataliya Korotkova Alexey Prosviryakov Andrey Bazlov Alexander Komissarov Dmitry Moskovskikh Microstructure and Hardness Evolution of Al8Zn7Ni3Mg Alloy after Casting at very Different Cooling Rates Metals composite materials hypereutectic aluminum alloys Al-Zn-Mg alloys rapid solidification eutectic CALPHAD |
| title | Microstructure and Hardness Evolution of Al8Zn7Ni3Mg Alloy after Casting at very Different Cooling Rates |
| title_full | Microstructure and Hardness Evolution of Al8Zn7Ni3Mg Alloy after Casting at very Different Cooling Rates |
| title_fullStr | Microstructure and Hardness Evolution of Al8Zn7Ni3Mg Alloy after Casting at very Different Cooling Rates |
| title_full_unstemmed | Microstructure and Hardness Evolution of Al8Zn7Ni3Mg Alloy after Casting at very Different Cooling Rates |
| title_short | Microstructure and Hardness Evolution of Al8Zn7Ni3Mg Alloy after Casting at very Different Cooling Rates |
| title_sort | microstructure and hardness evolution of al8zn7ni3mg alloy after casting at very different cooling rates |
| topic | composite materials hypereutectic aluminum alloys Al-Zn-Mg alloys rapid solidification eutectic CALPHAD |
| url | https://www.mdpi.com/2075-4701/10/6/762 |
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