激励电流对MGH956合金原位合金化TIG焊接头性能的影响  

Effect of Excitation Current on Tensile Properties of Joint of MGH956 Alloy by In-situ Alloying TIG Welding

作　　者：雷玉成[1,2] 龚晨诚 罗雅[1] 肖波[1,3] 朱强[1] 

机构地区：[1]江苏大学材料科学与工程学院,江苏镇江212013 [2]江苏大学江苏省高端结构材料重点实验室,江苏镇江212013 [3]江苏沙钢集团淮钢特钢股份有限公司,江苏淮安223002

出　　处：《材料工程》2015年第2期7-13,共7页Journal of Materials Engineering

基　　金：国家自然科学基金资助项目(51075191);江苏高校优势学科建设工程资助项目(PAPD);江苏省高校博士创新计划资助项目(cxlx12_0638)

摘　　要：通过高频调制TIG焊电弧激发超声,以自制焊料作为填充材料,在不同激励电流下对MGH956合金进行超声电弧原位合金化TIG焊接,研究了超声电弧对焊缝气孔分布、微观组织和接头性能的影响。结果表明:在激励电流为10A时,焊缝气孔尺寸明显变大,但数量减少,焊缝晶粒粗大;当激励电流提高到20A时,气孔数量急剧减少,焊缝晶粒细小均匀,颗粒状增强相弥散分布;激励电流增大到30A时,气孔进一步减少,但晶粒粗化。比较拉伸实验结果表明,激励电流为20A时,接头抗拉强度最高,为626MPa,达到了母材强度的87%,同时接头由沿晶脆性断裂变成韧-脆混合断裂形式。The arc-ultrasonic was excited by modulating the TIG arc through high frequency and the homemade solder was filled in the weld as filler composite.The effect of arc-ultrasonic on pores,microstructures and mechanical properties of MGH956 alloy joints produced by arc-ultrasonic in-situ alloying TIG welding with different excitation current was investigated.The results show that when the excitation current is 10 A,pores grow up obviously while the number of pores is reduced,moreover,the grains are coarse.When the excitation current increases to 20 A,the number of pores sharply decreases,the grains are fine and uniform,and the particle reinforced phases are uniformly distributed in the weld.When the excitation current increases to 30 A,the number of pores further decreases while the grains are coarsen.The tensile results indicate that the maximum tensile strength of the weld joint is achieved at an excitation current of 20 A,which is 626 MPa and reaches 87% of the base metal.The toughness of joints is improved obviously and the fracture surface changes from completely brittle fracture to ductile-brittle mixed fracture.

关 键 词：MGH956合金 超声电弧 TIG焊接 气孔 显微组织 

分 类 号：TG454[金属学及工艺—焊接]