细晶AZ61镁合金板材的CO_2激光焊接性能  

Weldability of Fine-grain AZ61 Magnesium Alloy Sheets by CO_2 Laser Beam Welding

作　　者：严红革[1] 陈小玲[1] 陈吉华[1] 苏斌[1] 

机构地区：[1]湖南大学材料科学与工程学院,湖南长沙410082

出　　处：《湖南大学学报（自然科学版）》2013年第11期84-88,共5页Journal of Hunan University:Natural Sciences

基　　金：国家自然科学基金资助项目(51274092)

摘　　要：采用CO2激光器对2mm厚的AZ61镁合金细晶板材分别进行了填充焊和自熔焊实验.研究了细晶镁合金板材的焊接性和填充带合金化稀土元素Ce对接头组织及力学性能的影响.结果表明,细晶板材的焊接接头热影响区不明显,组织较母材变化不大,半熔化区范围窄、液化程度低,未进行合金化的自熔焊焊缝组织较粗大,焊缝晶粒尺寸约15μm,而填充焊焊缝组织为平均晶粒尺寸是5μm的等轴晶,即合金化稀土元素Ce可细化焊缝组织,而且稀土元素Ce的加入能抑制柱状树枝晶区而扩大等轴晶区域范围.填带焊接头的平均抗拉强度和伸长率较自熔焊接头分别提高了6%和12%.Fine-grain magnesium alloy sheets possess high strength and excellent ductility,and finegrain AZ61 magnesium alloy sheets of 2.0 mm in thickness were welded with CO2 laser beam with filler metal and without filler metal.The weldability of fine-grain magnesium alloy sheets and the effect of the rare-earth element Ce in filler on fusion zone microstructure and mechanical properties were investigated.The results indicated that the rare-earth element Ce could refine microstructure,so that the grain size of joint without filler was much larger than that with filler and the former was about 15 μm and the latter was about 5 μm.Also,columnar dendritic grain range was restrained and equiaxed dendritic grain range was expanded resulting from the rare-earth element Ce.Additionally,there was little difference between heat affected zone （HAZ） and base metal and the extent of liquation in partially melted zone （PMZ） was low,and the range of HAZ and PMZ was narrow,which showed that the weldability of fine-grain AZ61 alloy sheets was good.The ultimate tensile strength and elongation of the weld with filler metal are 6 ％ and 12％ higher than the weld without filler metal.

关 键 词：镁合金 细晶板材 CO2激光焊 填充焊 自熔焊 焊接性能 

分 类 号：TG456.7[金属学及工艺—焊接]