Experiment on TLP diffusion welding of GH3230 alloy

Aiming at GH3230 alloy, the structural material of aeroengine hot end components, two kinds of amorphous interlayer for TLP diffusion welding were designed and manufactured, and experimental research on TLP diffusion welding process was carried out.Effects of amorphous interlayer, holding time and welding temperature on microstructure and mechanical properties of GH3230 alloy TLP diffusion welded joint were analyzed.Microstructure and element distribution during TLP diffusion welding were analyzed, and the maximum width of liquid phase and time required for isothermal solidification were determined.The results showed that No.2 interlayer with smooth surface and thickness of 0.025～0.035 mm obtained better welding quality under several process parameters, which was more suitable for TLP diffusion welding of GH3230 alloy.When holding time increased from 2 h to 8 h, defects in isothermal solidification zone continued to decrease, strength of joint first increased and then decreased, and strength reached the highest when holding time was 4 h.Welding temperature increased from 1 180 ℃ to 1 220 ℃, grains in isothermal solidification zone grew gradually, and strength increased first and then decreased, reaching maximum strength under the condition of 1 200 ℃ × 4 h, the maximum strength of joint was 887.68 MPa, which reached 97.6% of base metal, and weld did not crack after bending 90°.TLP diffusion welding of GH3230 alloy reached the maximum liquid phase width of 70 μm after holding for 2 h.Completion time of isothermal solidification process was between 2～4 h.