摘要
通过4043铝-硅焊丝实现了5052铝合金／Q235钢的钨极氩弧（TIG）熔-钎焊连接，运用OM、SEM和EDS分析了界面层的宏微观结构特征及金属间化合物成分，采用拉伸试验获得了焊接接头的断裂强度。研究结果表明：焊缝／低碳钢交界处形成了薄厚不均的界面层，钢侧坡口上部的界面层较厚，下部的界面层较薄，厚度范围为8-11μm；根据界面层的微观形态和相组成不同将界面层分为两层，靠近焊缝的I层为焊缝组织与金属间化合物交错生长的锁扣状，由τ-Al7.4Fe2Si＋τ6-FeAl4Si＋α（A1）相构成；靠近钢侧的Ⅱ层为致密的板块状，由θ-FeAl3＋η-Fe2Al5＋τ5相构成；接头抗拉强度约为84MPa，焊缝／低碳钢界面层下部为连接的薄弱环节，成为拉伸实验的起裂位置。
Gas tungsten arc(TIG) melt- brazing of 5052 aluminum alloy to Q235 steel was conducted using 4043 Al- Si filler metal.The macrostructure and microstructure of the joint as well as the composition of intermetallic compounds(IMCs) were analyzed by OM,SEM and EDS.Tensile strength of the joints was tested by instron universal testing machine.The results show that an uneven interfacial layer formed between weld seam and steel.The layer in the upper part of the steel side groove is thicker than that of the lower part,and the thickness range is from 8 ~ 11 μm.According to the microstructure and the composition,the interfacial layer is divided into two parts.The latch-like layer closing to the weld seam is staggered grown of weld metal and IMCs,which consists of t5-A1_(7.4)Fe_2Si + T_6-FeAl_4Si + a(Al) phase.The layer closing to the steel is compact plate- like phase,and consists of θ-FeAl_3 + η-Fe_2 Al_5+ Γ_5.The tensile strength of the joints is about 84 MPa,the lower part of the interfacial layer is the weak point and is the location of crack initiation.
出处
《焊接》
北大核心
2013年第5期39-42,70,共4页
Welding & Joining
关键词
钨极氩弧熔-钎焊
铝合金
低碳钢
界面层
力学性能
gas tungsten arc welding-brazing
aluminum alloy
low-carbon steel
interfacial layer
mechanical property
