基于过渡层的TiAl/GH3030异质高温合金激光焊接头组织与性能研究

Study on the Microstructure and Properties of TiAl/GH3030 Heterogeneous Superalloy Laser Welding Joint Based on Transition Layer

以0.26 mm V+0.2 mm Cu复合薄片作为过渡层,采用激光焊方法连接TiAl/GH3030异质高温合金,对接头的宏观和微观组织的形貌、物相、力学性能及断口进行分析。结果表明:添加过渡层可实现TiAl/GH3030异质高温合金的良好连接,焊缝成形后外观良好。焊缝区主要形成了白色(V,Cr)固溶体相、灰色等轴片层状AlNi 2Ti/(V,Cr)共晶组织、黄色晶间块状相Ni基固溶体(Ni,Cu)、浅黄色晶间相Cu基固溶体(Cu,Ni)。GH3030合金侧界面区未形成金属间化合物层,而TiAl合金侧形成了由AlCuTi和AlCu 2Ti构成的金属间化合物层,且界面层存在微裂纹缺陷。接头的平均抗拉强度为202 MPa,接头断裂于TiAl合金侧,AlCuTi和AlCu_(2)Ti金属间化合物相是导致接头脆化、力学性能降低的主要原因。

Using 0.26 mmV and 0.2mmCu composite as the transition layer,TiAl/GH3030 heterogeneous superalloy is connected by laser welding,and the analysis of the morphology,phase,mechanical properties and fracture surface of the macro and micro structures of the joint is conducted.The results show that adding a transition layer can achieve good connection of TiAl/GH3030 heterogeneous superalloy,and the appearance of the weld seam is good after forming.The weld zone mainly forms white(V,Cr)solid solution phase,gray equiaxed layer AlNi2Ti/(V,Cr)eutectic structure,yellow intergranular block phase Ni based solid solution(Ni,Cu),and light yellow intergranular phase Cu based solid solution(Cu,Ni).There is no intermetallic compound layer formed in the interface area of GH3030 alloy,while the intermetallic compound layer composed of AlCuTi and AlCu2Ti is formed on the TiAl alloy side,and there are microcrack defects in the interface layer.The average tensile strength of the joint is 202 MPa,and the joint fractures on the side of TiAl alloy side.The AlCuTi and AlCu_(2)Ti intermetallic compound phases are the main reasons for the embrittlement and reduced mechanical properties of the joint.