12Mg17相組成的共晶層，平均厚度為38.83 μm。在鎂側(cè)界面上部還發(fā)現(xiàn)一層厚度為12.3 μm的連續(xù)柱狀A(yù)l3Mg2層，垂直于Al3Mg2層與共晶層的邊界。在鎂側(cè)界面的中部和底部，只有Al3Mg2層和Al12Mg17層，其厚度沿厚度方向從上到下依次減小。此外，鋁側(cè)和鎂側(cè)界面的Al3Mg2層具有較高的平均晶粒取向差，這為鋁和鎂原子間的擴(kuò)散提供了一條途徑。當(dāng)轉(zhuǎn)速為600 r/min時(shí)，Mg固溶體與Al12Mg17相組成的共晶層沿厚度方向分布在鎂側(cè)界面上，共晶層厚度較低轉(zhuǎn)速（375 r/min）時(shí)顯著增加。鎂側(cè)界面上部的Al3Mg2層和共晶層的平均厚度分別為32.89和68.92 μm。最后，由轉(zhuǎn)速引起的應(yīng)變速率對(duì)金屬間化合物的生長(zhǎng)起著重要作用。;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+Al12Mg17), with an average thickness of 38.83 μm, appears at the upper of the Mg side interface. A continuous columnar Al3Mg2 layer with a thickness of 12.3 μm, perpendicular to the boundary between the Al3Mg2 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 Al3Mg2 layer and Al12Mg17 layer, the thickness of which decreases sequentially from the upper to the bottom along the thickness direction. In addition, the Al3Mg2 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 Al12Mg17 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 Al3Mg2 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."/>