纳米TiC复合焊丝和7075铝合金的脉冲TIG焊组织和性能及工艺优化  

Microstructures performance and welding process of pulse TIG welded 7075 aluminum joints prepared with nano TiC aluminum matrix composite filler

作　　者：聂志坚 秦颐鸣 龙金海 陈基朗 卢悦 唐鑫[1] Nie Zhijian;Qin Yiming;Long Jinhai;Chen Jilang;Lu Yue;Tang Xin(Guilin University of Technology,Guilin 541004,Guangxi,China;Guangxi Institute of Industrial Technology,Nanning 530000,China)

机构地区：[1]桂林理工大学,广西桂林541004 [2]广西产业技术研究院,南宁530000

出　　处：《焊接》2023年第4期29-36,共8页Welding & Joining

基　　金：广西科技重大项目(桂科AA17129005)。

摘　　要：使用纳米TiC复合(Al-Zn-Mg-Cu)焊丝对7075-T651铝合金板材进行交流脉冲钨极氩弧焊(tungsten inert gas,TIG),以焊缝抗拉强度为响应值,通过正交试验分析优化焊接脉冲电流、脉冲频率和焊接速度3个参数,对不同工艺下的焊缝进行拉伸测试、气孔率分析和微观组织分析。结果表明,在焊接电流过高和焊接速度过低时,容易导致纳米颗粒聚集,氢气泡在颗粒处形核并汇集长大,形成气孔。通过正交试验法探究纳米TiC复合焊丝焊接7075铝合金的最佳工艺为基值电流160 A,脉冲电流180 A,脉冲频率100 Hz,焊接速度3 mm/s。在合适的焊接工艺下,纳米颗粒在基体中的均匀分散,同时可以抑制晶内析出相长大,提高焊接接头性能。The nanocomposite welding wire(Al-Zn-Mg-Cu)was used for AC pulse TIG(tungsten inert gas)welding of 7075-T651 superhard aluminum alloy.In response to the design value of tensile strength,the welding process parameters,such as welding pulse current,welding frequency and welding speed,were optimized by orthogonal test method.The tensile properties,welding pores and microstructures of welded joints with different process parameters were analyzed.The results showed that excessive welding pulse current and low welding speed can induce nanoparticles clustering and hydrogen bubbles nucleate at the particles grow up to pores.For tensile strength of welded joints,the optimum process parameters were welding base current 160 A,pulse current 180 A,welding frequency 100 Hz,welding speed 3 mm/s.The suitable process parameters favored the dispersion of nanoparticles and restrained the size of intracrystalline precipitation phases,which could improve the performance of welded joints.

关 键 词：铝基复合材料 7075铝合金 显微组织 焊接气孔 正交试验 

分 类 号：TG442[金属学及工艺—焊接]