Research On GH536/GH738 Laser Deposition Repair Technology

GH738 alloy(US brand Waspaloy)is suitable for the production of aero-engine turbine discs,sealing rings and other components.Under complex working environments such as high temperature and high pressure,these parts are prone to wear,edge corrosion,cracks and other damage failures.Laser deposition repair technology has the advantages of small heat input and near-net repair,which has obvious technical advantages in the field of damaged parts repair.When the GH738 alloy damaged specimen is repaired by the homogenous material and carried out to aging heat treatment,the hardness of the repaired zone is higher than that of the substrate.In order to avoid wearing fittings excessively in service,the repairing material with lower hardness should be selected,according to the principle of similar thermal expansion coefficient and similar melting point.In order to obtain a well-fused and defect-free deposit layer microstructure,the single track laser deposition test of GH536/GH738 alloy was carried out,the influence of process parameters on the feature size of single-track sedimentary layer was analyzed.The low-power parameters were selected for multi-layer deposition test.The microstructure quality of sedimentary layer under each parameter was compared,and the process parameters were optimized for the subsequent test.Based on the optimized parameters,the laser deposition GH536/GH738 alloy repair test was carried out.The morphology,quantity and distribution of ?'phase and carbide are summarized.The mechanical properties of the repaired samples were tested and analyzed,which provide guidance for optimizing the laser repair process.After laser deposition repair,the deposited microstructure is usually metastable,and the heat treatment can optimize the structure and improve the mechanical properties of the part.Two-stage aging heat treatment at different temperatures and solid solution aging heat treatment tests were carried out.The effects of different heat treatment on the microstructure and mechanical properties of the repaired samples were analyzed.Theoretical support is provided to the optimization of heat treatment process of parts.