含钪铝合金变极性TIG焊接头组织与性能  

Microstructures and mechanical properties of aluminum alloy with Sc welded joints by variable polarity TIG welding

作　　者：苏志强[1] 周庆[1] 田志杰[1] 杜晗[1] 熊林玉[1] 张勤练[2] 蔡玉博 林三宝[2] 鄢江武 攀世华 

机构地区：[1]首都航天机械公司,北京市100076 [2]哈尔滨工业大学先进焊接与连接国家重点实验室,150001 [3]先进技术湖北省重点实验室,孝感市432100

出　　处：《焊接》2014年第9期45-48,75,共4页Welding & Joining

摘　　要：采用变极性TIG焊接工艺对6 mm厚5B70含钪铝合金板材进行了焊接试验,对焊接接头的组织和力学性能进行了研究,分析了钪元素的作用。研究结果表明:接头的抗拉强度最高可达368 MPa,强度系数为0.89,断后伸长率为10.7%;断裂发生在熔合线处,断口形貌为韧窝;焊缝两侧硬度值最低,焊缝中心硬度稍高。在钪元素的作用下,焊缝组织得到了明显细化,熔合区形成的等轴晶层增强了焊缝与基材的相容性,热影响区的再结晶受到了抑制,接头的抗软化能力和抗拉强度提高。5B70 Al-Mg-Sc alloy plates with thickness of 6 mm was welded by variable polarity TIG welding.The microstructures and mechanical properties of the joints were studied.Also,the effect of the alloy element Sc was analyzed.Experimental results indicated that the joints with excellent mechanical properties can be obtained.The tensile strength can reach up to 368 MPa,which was the 89%of that of the base metal and the maximum elongation at fracture is 10.7%.The fracture occurs at the fusion zone near the fusion line.The fracture appearance of the joint is the dimple which indicates the plastic fracture mode.The Viker hardness in the center of the weld zone is little higher than that in the other zones.With the effects of the element Sc,microstructures in weld zone is refined,the equiaxed grain layer in fusion zone improves the compatibility between the weld and the base metal,the recrystallization in heat affected zone is inhibited and the softening resistance and tensile strength of the joint are improved.

关 键 词：铝镁钪合金 变极性氩弧焊 焊缝组织 力学性能 

分 类 号：TG442[金属学及工艺—焊接]