Mg-Al-Zn (AZ31) of 10-mm thick plates were subjected to friction stir welding (FSW) using a conventional tool (CT) and bobbin tool (BT), respectively. The microstructure, room temperature tensile properties, dynamic compressive mechanical properties, and corrosion resistance of the base metal (BM) and various regions of the friction stir welded joints were investigated systematically. The mean grain size, dislocation density, and precipitate distribution in the various regions of the friction stir welded joints were various due to different thermal cycle and plastic deformation. Compared with the CT, a relatively more homogeneous microstructure, a larger number of high-density dislocations and precipitates were produced in the various regions of the joint prepared by the BT due to higher thermal cycle and strain rate. As a result, the friction stir welded joint prepared by the BT exhibits excellent tensile properties and dynamic compressive mechanical properties, and outstanding corrosion resistances compared to those of the CT. In addition to slight changes in tensile properties and dynamic compressive mechanical properties, the corrosion resistance of the joint prepared by the BT was significantly improved compared to the BM. FSW with BT was suggested to be the optimal method to weld AZ31 alloy thick plate.

使用常规工具（CT）和线轴工具（BT）分别对10毫米厚的Mg-Al-Zn（AZ31）进行摩擦搅拌焊接（FSW）。系统地研究了贱金属（BM）和搅拌摩擦焊接接头各个区域的组织，室温拉伸性能，动态压缩力学性能和耐腐蚀性。由于热循环和塑性变形的不同，摩擦搅拌焊接接头各区域的平均晶粒尺寸，位错密度和析出物分布各不相同。与CT相比，由于较高的热循环和应变率，在BT制备的接头的各个区域中产生了相对更均匀的微观结构，大量的高密度位错和沉淀。结果是，与CT相比，由BT制备的搅拌摩擦焊接接头具有出色的拉伸性能和动态压缩机械性能，以及出色的耐腐蚀性。除了拉伸性能和动态压缩机械性能的微小变化外，与BM相比，由BT制备的接头的耐蚀性得到了显着改善。BT的FSW被认为是焊接AZ31合金厚板的最佳方法。与BM相比，BT制备的接头的耐腐蚀性得到了显着提高。BT的FSW被认为是焊接AZ31合金厚板的最佳方法。与BM相比，BT制备的接头的耐腐蚀性得到了显着提高。BT的FSW被认为是焊接AZ31合金厚板的最佳方法。