镁合金厚板载流搅拌摩擦焊接头的组织与力学性能

Research on the microstructure and mechanical properties of magnesium alloy plank by electronic current aided friction stir welding

采用载流搅拌摩擦焊方法进行20 mm厚AZ31B镁合金厚板的单面单道次对接焊实验,并测试和分析接头内部缺陷、金相组织、物相组成和力学性能。结果表明:该方法可以使镁合金厚板获得较佳质量的焊接接头;接头焊核区由α-Mg相组成且晶粒显著细化;接头系数达94.5%,接头正弯强度、背弯强度和冲击吸收功分别达到母材的122.5%、103.8%、168%;接头硬度最低值位于前进侧热影响区。

The AZ31B magnesium alloy plank is butt welded by one side single-pass by electronic current aided friction stir welding.And the internal defects,microstructure,phase composition and mechanical properties are tested and analyzed.The results show that the welded joint is good and the nugget zone is composed of α-Mg phase and the grains are refined. Moreover,the welded joint efficiency reaches 94.5% ,and the positive bending strength,back bending strength and impact absorbing energy reaches 122.5%, 103.8% and 168% that of the base material respectively.Furthetanore,the minimum surface hardness is in the heat ＇affected zone on the advancing side.