钢铌激光焊接头金属间化合物调控工艺研究
毕业论文关键词：钢/铌；激光焊接；金属间化合物；Ag-V过渡层 Abstract Steel/niobium compound welding structure can improve operating temperature of the aircraft engine,reduce its weight and make the aircraft engine with higher thrust to weight ratio.Steel/niobium compound welding structure has broad application and development prospects in the aerospace field.It is the hot spot of academic research. In this paper,the laser welding is used to connect the steel and niobium.The microstructure and composition of the welded joint were observed and analyzed by optical microscope,EDS,XRD and energy spectrometer. Research results show that laser welding can realize the connection of steel and niobium under certain technological parameters. Intermetallic compound layer will be produced in the weld metal after the direct welding of niobium and 304 stainless steel. Because of the existence of the intermetallic compound layer, the cracking tendency of the welded joint can be increased and the strength of the weld is reduced.The intermetallic compound layer can even lead to fracture.Because of the direct welding joint is easy to produce intermetallic compounds,this paper studies adding the filling layer in the weld.The connection of niobium and 304 stainless steel can be realized by adding Ag-V filling layer in the weld.The research shows that there are few metal compounds in the weld after adding the filler layer.Because the filling layer is added in the weld,the metal compound in the weld is reduced.The cracking tendency of the welding joint is reduced and the connection is realized.The strength of joints of Ag-V filled layer is higher than that of Ag-Mo,Cu-V,and Cu-Mo filling layer.
Key words: steel /niobium; laser welding; intermetallic compound; Ag-V filling layer
目录
第一章绪论.....1
1.1课题的背景和意义.....1
1.2不锈钢与铌的焊接性...2
1.2.1根据物理性能分析不锈钢与铌的焊接性.....2
1.2.2根据冶金学分析不锈钢与铌的焊接性.3
1.3不锈钢与铌的焊接研究现状...5
1.3.1熔化焊...5
1.3.2钎焊.....6
1.3.3熔钎焊...7
1.3.4爆炸焊...8
1.4金属间化合物....9
1.5课题主要研究内容.....10
第二章实验材料、设备和方法.....11
2.1实验材料11
2.2激光焊接设备...12
2.3激光焊接实验..13
2.3.1焊前准备13
2.3.2施焊....13
2.4分析测试方法..14
2.4.1焊接接头拉伸试验....14
2.4.2微观组织分析..14
2.4.3断口形貌分析..15
2.4.4相组成分析....15