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利用钨极氩弧焊方法,在无填充材料和不开坡口条件下获得了AZ91D镁合金的焊接接头。利用扫描电镜和能谱分析了焊缝组织形貌和成分,测试了接头的显微硬度分布。结果表明:利用钨极氩弧焊方法,在焊接电流为152A、弧焊电压13.4V、焊接速度6.5mm/s以及采用20L/min的氩气焊接工艺条件下,可以实现3.4mm厚度的AZ91D镁合金的连接,接头情况良好;焊缝组织主要由黑色基体相α-Mg、白色块体(α+Mg17Al12)共晶体和灰色块体组成;焊缝宽度可达7mm,焊缝区平均显微硬度达到64.5HV0.2,母材的显微硬度为56.3HV0.2,接头显微硬度曲线过渡平滑。
The welding joint of AZ91D magnesium alloy was obtained by using TIG welding method without filler and with no groove. The microstructure and composition of the weld were analyzed by SEM and EDS, and the microhardness distribution of the joint was tested. The results show that AZ91D magnesium with thickness of 3.4mm can be achieved by using TIG welding method under the condition of a welding current of 152A, an arc welding voltage of 13.4V, a welding speed of 6.5mm / s and an argon gas welding process of 20L / min The joints and joints are good. The weld microstructure mainly consists of black matrix phase α-Mg, white block (α + Mg17Al12) cocrystal and gray block. The weld width can reach 7mm. The average microhardness Reached 64.5HV0.2, the base metal microhardness of 56.3HV0.2, joint microhardness curve smooth transition.