对传统轧制态(R)GH4169板材和SLM增材制造(3D)GH4169板材分别进行激光焊接,采用光学显微镜、扫描电镜、能谱仪对接头显微组织特征进行表征,并对接头进行显微硬度和拉伸测试。试验结果表明熔合区显微组织主要由胞晶向枝晶或柱状晶转变,晶内和晶间区域存在大量δ相和laves相。R/3D GH4169接头、R/R GH4169接头和3D/3D GH4169接头的晶粒尺寸和析出相尺寸依次减小,熔合区平均显微硬度依次增加(250 HV,261 HV,274 HV),接头拉伸强度依次增加(768 MPa,799 MPa,985 MPa)。R/3D GH4169接头和R/R GH4169接头断裂以韧性断裂为主,而3D/3D GH4169接头主要为脆性断裂。

A conventional rolled (R) GH4169 sheet and a selective laser melting (SLM) additive-manufactured (3D) GH4169 sheet were welded to comparatively investigate the microstructure and mechanical properties of the three (R/3D, R/R, and 3D/3D) welded joints. Optical microscopy, scanning electron microscopy, and energy-dispersive spectrometry were used to characterize the microstructure of the butt joints; microhardness and tensile tests were also performed on the butt joints. The test results show that the microstructure of the fusion zone is mainly transformed from cell crystals to dendrites or columnar crystals and a large number of δ phases and laves phases are formed in the intergranular and intragranular regions. The grain size and precipitated phase size of the R/3D GH4169 joint, R/R GH4169 joint, and 3D/3D GH4169 joint decrease in sequence, the average microhardness of the fusion zone increases successively (250 HV, 261 HV, and 274 HV, respectively), and the tensile strength of the joints increases successively (768 MPa, 799 MPa, and 985 MPa, respectively). The fracture mode of the R/3D GH4169 and R/R GH4169 joints is mainly ductile fracture, whereas the fracture mode of the 3D/3D GH4169 joint is brittle fracture.