Microstructure And Property Research Of Laser Deposition Repair GH738 Alloy

GH738 high temperature alloy is mainly used for turbine disk,seal ring,oil thrower,because of its bad working conditions,corrosion,wear and crack are prone to occur during the service process,which affect the performance of engine and cause potential risks.To short the maintenance cycle and reduce the cost,this paper repaired the penetration damage occurred during the service of GH738 alloy parts by Laser Deposition Repairing(LDR).The effects of process parameters on characteristic dimension of GH738 alloy were investigated by orthogonal test,the parameters were optimized and zero defect samples were obtained;then the reasons of defects such as ill bonding,cracks in deposition zone and the characters of microstructure,microhardness were analyzed.Aiming at the penetrating damage,the GH738 alloy parts with through-groove damage were repaired by LDR,microstructure and its influence on tensile properties of laser deposition repairing samples were analyzed.To improve the mechanical properties of the repair samples,and meet the service demand,the effects of bipolar aging heat treatment on the microstructure and mechanical properties were studied.The effects of different heat treatment temperature on the carbides and strengthening phase of the repaired samples were summarized;then the tensile properties were tested at room temperature;Optimized heat treatment scheme which is applicable for GH738 alloy repaired by LDR was selected.