Effect of Rotational Speed on Intermetallic Compounds and Low Melting Point Eutectic of Al/Mg Friction Stir Welded Joints
Effect of Rotational Speed on Intermetallic Compounds and Low Melting Point Eutectic of Al/Mg Friction Stir Welded Joints
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转速对Al/Mg搅拌摩擦焊接头金属间化合物和低熔点共晶的影响
DOI：
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发表时间：
2021
期刊：
影响因子：
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通讯作者：
Chen Yi
中科院分区：
文献类型：
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作者：
Xu Yang;Ke Liming;Mao Yuqing;Chen Yi
研究了转速对Al/Mg搅拌摩擦焊接头金属间化合物和低熔点共晶组织的影响。利用电子背散射衍射仪对Al和Mg界面的微观结构进行了表征。结果表明，在低转速（375 r/min）条件下，Mg侧界面上部出现了平均厚度为38.83 μm的Mg+Al 12 Mg 17共晶层;在Mg侧界面的上部，垂直于Al_3Mg_2层与共晶层的界面，还发现了一层厚度为12.3 μm的连续柱状Al_3Mg_2层。在Mg侧界面的中部和底部，只有Al_3Mg_2层和Al_（12）Mg_（17）层，其厚度沿着厚度方向从上到下依次减小。此外，在Al和Mg侧界面处存在的具有高晶粒平均取向差的Al_3Mg_2层为Al和Mg原子的扩散提供了通道。当转速为600 r/min时，由Mg固溶体和Al_（12）Mg_（17）相组成的共晶层沿厚度方向沿着分布在Mg侧界面上，与低转速（375 r/min）相比，共晶层厚度显著增加。2层和共晶层的厚度分别为32.89和68.92 μm。最后，由转速引起的应变速率对金属间化合物的生长起着重要的作用。
The effects of rotational speed on the intermetallic compounds and low melting point eutectic of Al/Mg friction stir welded joints were investigated. The interfacial microstructures of both Al and Mg sides were characterized by electron backscatter diffraction. The results show that when the low rotational speed of 375 r/min is used, the eutectic layer(Mg+Al_(12)Mg_(17)), with an average thickness of 38.83 μm, appears at the upper of the Mg side interface. A continuous columnar Al_3Mg_2 layer with a thickness of 12.3 μm, perpendicular to the boundary between the Al_3Mg_2 layer and eutectic layer, is also found at the upper of the Mg side interface. At the middle and bottom of the Mg side interface, there are merely Al_3Mg_2 layer and Al_(12)Mg_(17) layer, the thickness of which decreases sequentially from the upper to the bottom along the thickness direction. In addition, the Al_3Mg_2 layer with high kernel average misorientation at the Al and Mg side interface provides a path for the diffusion of Al and Mg atoms. When the high rotational speed of 600 r/min is used, the eutectic layer composed of Mg solid solution and Al_(12)Mg_(17) phase is distributed across the Mg side interface along the thickness direction, and the thickness of the eutectic layer increases significantly compared with that at the low rotational speed of 375 r/min. The average thickness of the Al_3Mg_2 layer and eutectic layer on the upper of the Mg side interface is 32.89 and 68.92 μm, respectively. Finally, the strain rate caused by rotational speed plays an important role in the growth of intermetallic compounds.