Investigation On Laser Welding Process Of GH3039 And Microstructure And Properties Of Welded Joint

High-temperature alloys have a high tensile strength at elevated temperature, a good stability and reliability in a large range of temperatures. Among these superalloys, nickel-base superalloys are widely used as thermal components in the turbojet engine. GH3039 alloy, one of Nickel-base wrought superalloys, has a good oxidation resistance below 1000℃, stable microstructure along with good cold forming and welding performance, so it is suitable for the manufacture of components of aero-engine combustion chamber and afterburner. As the laser welding technology has the characteristics of the energy density, heat concentration and large aspect ratio of welding seam, it is usually chosen to weld the nickel-base superalloy.In this investigation, GH3039 alloy plate with a thickness of 1mm was welded utilizing the pulsed laser welding, and some joints were solution-treated. The mechanical properties, fracture morphology and microstructure of GH3039 welded joints were characterized by tensile test, hardness measurement, optical microscopy, scanning electron microscopy, and energy dispersive In comparison with the performance of GH3039 welding joints and GH3030 laser welding joint, the mechanism of microstructure refinement was understood by the relationship of welding performance and microstructure and understood, and the effect of solution treatment on the joint performance was studied.The results show that good welded joints can be got at appropriate processing parameters. GH3039 laser-welded joints have the same tensile strength as the parent material at room temperature and at elevated temperatures; The microstructure of weld joint consists of austenitic matrix, columnar crystal in the form of V shape close to the fusion line and fine equiaxed austenite in the centre. The welded joint presents a lamellar morphology, but there is no obvious segregation and remarkable influence of the Joint Microstructure and Properties; After solution treatment, the weld grains become coarse along with a large amount of granular precipitates dispersed in weld zone and base metal zones.