铸态AZ91D镁合金双面TIG焊焊接接头组织研究
Microstructure of Welded Joint of Die-cast AZ91D Alloy Plates Welded by TIG
郭 强1， 游国强1.2， 武婧亭1
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作者单位：(1.重庆大学 材料科学与工程学院， 重庆 400030； 2.国家镁合金材料工程技术研究中心, 重庆 400030)
中文关键字：AZ91D镁合金； TIG焊； 焊接接头； 微观组织
英文关键字：AZ91D alloy; TIG; welded joint; microstructure
中文摘要： 对3 mm厚铸态镁合金进行TIG焊研究，采用交流、双面焊接，其正面焊接电流为120A，背面焊接电流分别为80、90、100A，焊接速度和保护气体流量不变，焊接完成后按照标准程序对焊缝取样，用光学显微镜观察焊接接头的微观组织。分析表明：焊缝表面成形不好，焊缝表面存在明显缺陷；随着背面焊接电流的增加，焊缝中网状β-Mg17Al12相减少，而颗粒状的β-Mg17Al12相增多。
英文摘要：As-cast AZ91D alloy plate with 3 mm thickness was welded by both sides using TIG. The welding process was that the current of first side was AC 120A and that of reverse side was 80A, 90A and 100A, the welding speed and protection gas flow was constant. After welding, the cross-sections of the sample were prepared using standard procedures. The microstructure was investigated by optical microscopy. The results show that the surface appearance of the weld beads is not good, there are some visible defects; with the increase of electric current of reverse side, the amount of the continuous β-Mg17Al12 phase decrease, while the amount of the granular β-Mg17Al12 phase increase.