Effect of Pulse Current Duration on Microstructure and Properties of Laser Deposition Repaired GH4169 Superalloy after Pulse Current Treatment

GH4169 superalloy laser deposited on the GH4169 superalloy to fabricate the repair sample. Subsequently, 1 050 ℃×30 min solution treatment and pulse current treatment with different durations （5, 10, 20 min） of electrical conduction were carried out. The effects of the pulse current duration on the microstructure and tensile properties of the alloy were studied. The results show that compared with superalloy before the pulse current treatment, the volume fraction and size of laves phases of the laser deposition alloy after pulse current treatment decreased, and the tensile strength and yield strength increased. With the increase of the pulse current duration, the volume fraction and size of Laves phases decreased, the tensile strength and yield strength increased, and the density of the ductile pits at the tensile fracture surface increased, with the size and depth decreasing. The tensile fracture surfaces were all located in the laser deposited alloy. When the pulse current duration was 20 min, the tensile strength and yield strength were the largest, which increased by 17% and 6% respectively compared with superalloy before the pulse current treatment.