| Effect of Rare Earths on Hot Cracking Resistant Property of Mg-Al Alloys |
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| 作者姓名： | 郑伟超 李双寿 汤彬 曾大本 郭旭涛 |
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| 作者单位： | [1]Fundamental Industry Training Center [2]Department of Mechanical Engineering [3]Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China |
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| 摘 要： | The effect of rare earths （RE） ranging from 0.1% to 1.2%（mass fraction） on hot cracking resistant property of Mg-Al alloys was investigated. The results show that hot cracking resistant property of Mg-Al alloys remarkably declines with an increase of RE addition. The causes of the decline are as follows： First, grain coarsening of Mg-Al alloys caused by RE addition reduces the fracture strain required for hot crack initiation. Second, RE reduces the eutectic microstructure of Mg- Al alloys, and as a result, shortens the time that the feeding channel remains open, making it difficult to feed the alloy. Furthermore, RE elevates the eutectic reaction temperature, which leads to the decrease in the strength of the interdendritic liquid film at the late stage of solidification. Third, when a-Mg dendrites form continuous skeletons, the interdendritic Al11 RE3 phase tends to block the feeding channels and increases the difficulty of feeding. Last, the shrinkage ratio discrepancy between Al11RE3 phases and α-Mg matrix is prone to cause shrinkage stress and promote hot crack initiation.
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| 关 键 词： | Mg-Al合金 镁合金 稀土 热裂纹 |
| 文章编号： | 1002-0721（2006）03-0346-06 |
| 收稿时间： | 2006-02-24 |
| 修稿时间： | 2006-03-28 |
Effect of Rare Earths on Hot Cracking Resistant Property of Mg-Al Alloys |
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| Weichao , Shuangshou Li, Bin Tang, Daben Zeng,Xutao Guo.Effect of Rare Earths on Hot Cracking Resistant Property of Mg-Al Alloys[J].Journal of Rare Earths,2006,24(3):346-351. |
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| Authors: | Weichao Shuangshou Li Bin Tang Daben Zeng Xutao Guo |
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| Affiliation: | aFundamental Industry Training Center, Tsinghua University, Beijing 100084, China;bDepartment of Mechanical Engineering, Tsinghua University, Beijing 100084, China;cDepartment of Engineering Mechanics, Tsinghua University, Beijing 100084, China |
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| Abstract: | The effect of rare earths (RE) ranging from 0.1% to 1.2%(mass fraction) on hot cracking resistant property of Mg-Al alloys was investigated. The results show that hot cracking resistant property of Mg-Al alloys remarkably declines with an increase of RE addition. The causes of the decline are as follows: First, grain coarsening of Mg-Al alloys caused by RE addition reduces the fracture strain required for hot crack initiation. Second, RE reduces the eutectic microstructure of MgAl alloys, and as a result, shortens the time that the feeding channel remains open, making it difficult to feed the alloy.Furthermore, RE elevates the eutectic reaction temperature, which leads to the decrease in the strength of the interdendritic liquid film at the late stage of solidification. Third, when α-Mg dendrites form continuous skeletons, the interdendritic Al11 RE3 phase tends to block the feeding channels and increases the difficulty of feeding. Last, the shrinkage ratio discrepancy between Al11RE3 phases and α-Mg matrix is prone to cause shrinkage stress and promote hot crack initiation. |
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| Keywords: | Mg-Al alloys hot cracking rare earths |
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