(Y, Gd)H2 phase formation in as-cast Mg-6Gd-3Y-0.5Zr alloy
In this work, a new (Y, Gd)H2 precipitate was identified and systematically investigated in the as-cast Mg-6Gd-3Y-0.5Zr alloy by XRD, SEM with EDS, TEM with EDS techniques and thermodynamics analysis. Results show that the as-cast alloy contains α-Mg, Mg24(Gd, Y)5, and (Y, Gd)H2 phase. The (Y, Gd)H2...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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Foundry Journal Agency
2021-05-01
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| Series: | China Foundry |
| Subjects: | |
| Online Access: | http://www.foundryworld.com/Public/Uploads/other_img/uploadfile/176498492660ba14130f5a8.pdf |
| Summary: | In this work, a new (Y, Gd)H2 precipitate was identified and systematically investigated in the as-cast Mg-6Gd-3Y-0.5Zr alloy by XRD, SEM with EDS, TEM with EDS techniques and thermodynamics analysis. Results show that the as-cast alloy contains α-Mg, Mg24(Gd, Y)5, and (Y, Gd)H2 phase. The (Y, Gd)H2 phase usually forms near the eutectic phase Mg24(Gd, Y)5 or in the α-Mg grains, displaying a rectangle-shape. The Mg24(Gd, Y)5 and (Y, Gd)H2 phases crystalize in bcc and fcc structure, respectively, and the (Y, Gd)H2 phase has a semi-coherent relationship with α-Mg matrix. The thermodynamics calculation results reveal that the hydrogen dissolved in the melt leads to the formation of hydrides. It is also found that the (Y, Gd)H2 hydride can form directly from the liquid phase during solidification. Additionally, it can precipitate by the decomposition of Mg24(Gd, Y)5 phase due to absorbing hydrogen from the remaining melt. |
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| ISSN: | 1672-6421 1672-6421 |