AZ91D镁合金钨极氩弧焊接头组织性能分析
Microstructure and Properties of Welded Joints of AZ91D Alloy by TIG Welding
徐培全1，李永平2，陆腾佳1，于治水1
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作者单位：（1.上海工程技术大学 材料工程学院，上海 201620；2.上海工程技术大学 航空运输学院，上海 201620）
中文关键字：镁合金;钨极氩弧焊;显微组织;显微硬度
英文关键字： magnesium alloy; tungsten inert gas welding; microstructure; microhardness
中文摘要：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152 A、弧焊电压13.4 V、焊接速度6.5 mm/s以及采用20 L/min的氩气焊接工艺条件下,可以实现3.4 mm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7 mm,焊缝区平均显微硬度达到64.5 HV0.2,母材的显微硬度为56.3 HV0.2,接头显微硬度曲线过渡平滑。
英文摘要：The welded joint of AZ91D magnesium alloy was obtained by TIG welding without filler materials and groove. The microstructure, morphology, composition and microhardness distribution of the welded joint were investigated using SEM (scanning electronic microscopy), EDAX and micro hardness tester. The results show that the welded joint of the alloy using TIG welding is obtained under the condition of welding current 152 A, welding voltage 13.4 V, welding velocity 6.5mm/s and 20 L/min Argon shielding gas. The microstructure of the welded joint consists of black matrix phase α-Mg, white eutectic(α+Mg17Al12) and gray dendrite. The weld width can reach 7mm; the smooth transition curve of micro hardness was obtained. The average micro hardness through welded seam is 64.5HV0.2; and the micro hardness of body materials is 56.3HV0.2.