Effect Of Process And Heat Treatment On Microstructure And Properties Of GH3039 Superalloy Prepared By Wire And Laser Additive Manufacturing

GH3039 alloy is an important structural material for gas turbine and aero engine casings,and it has been applied in structural and functional integrated high performance casings prepared by wire and laser additive manufacturing and subtractive manufacturing.In this paper,the influence of deposition parameters on the microstructure and microhardness of WLAM GH3039 alloy single layer was studied,and the effects of deposition parameters on the microstructure and microhardness of WLAM GH3039 alloy were described.The influence mechanism of laser remelting energy density on the microstructure and microhardness of single-channel double-layer GH3039 was studied.The influence mechanism of laser remelting energy density on the microstructure and microhardness of single-channel double-layer GH3039 was investigated.Based on the above research,the effects of remelting energy density and solution treatment on the microstructure,tensile properties and thermal corrosion properties of single-channel multilayer were investigated.The influence principle of heat treatment on microstructure and properties of GH3039 deposition layer of laser fuse was clarified.The main research contents and results are as follows:The single-channel single-layer deposition process of WLAM GH3039 alloy was studied,and the microstructure and process mapping relationship was determined.The effects of deposition parameters on forming quality,microstructure and microhardness of the deposited layer were analyzed by changing scanning speed Vs,laser power P and wire feed speed V_f.The primary dendrite spacing increased with the increasing of V_sand P,and decreased with the increasing of V_f.The mean microhardness of single channel monolayer increases with V_s increasing.The optimal deposition parameters were determined:V_s=3 mm/s,P=3000 W,V_f=25 mm/s.The effect of laser remelting energy density on the microstructure and microhardness of single-channel double-layer was studied.The microstructure of single-channel double-layer GH3039 alloy obtained by changing the remelting energy density is mainly composed of columnar crystals and equiaxed crystals,which are columnar crystals,columnar-equiaxed crystals and equiaxed crystals from the bottom up,respectively.The dendrite spacing decreases with the increase of the remelting energy density.The microstructure of single-channel double-layer GH3039 alloy obtained by changing the remelting energy density is mainly composed of columnar crystals and equiaxed crystals.The structures of the sample from bottom to top are columnar,columnar-equiaxed and equiaxed,respectively.The dendrite spacing decreases with the increase of the remelting energy density.With the increase of energy density of remelting,the average microhardness of single-channel double-layer increases first and then decreases.From top to bottom of the sample,the microhardness increases first and then decreases.The effect of interlayer laser remelting on the microstructure and properties of GH3039 multilayer alloy was investigated.The interlayer laser heat treatment can refine the microstructure effectively and improve the mechanical properties and thermal corrosion properties of GH3039 alloy.Interlayer remelting heat treatment reduces the dendrite spacing,and the dendrite spacing increases with the increase of remelting energy density.At low remelting energy density,the segregation of alloy elements occurs and the segregation elements are distributed along the dendrite stem.With the increase of remelting energy density,element segregation decreases.The tensile strength and yield strength of single-channel multilayer at room temperature decrease from bottom to top,while the elongation increases.Remelting energy density of 100J/mm can increase yield strength,tensile strength and elongation by 13.73%,13.99%and 18.81%,respectively.Interlayer remelting can effectively improve the thermal corrosion performance of single-channel multilayer cross section.When the remelting energy density is 100 J/mm,the thermal corrosion resistance increases by about 30.7%.With the increase of remelting energy density,the thermal corrosion performance of the sedimentary layer decreases.The effect of solution treatment on the microstructure and properties of WLAM GH3039 single-channel multilayer sample was studied.Solution treatment can effectively improve the tensile properties and thermal corrosion resistance of single-channel multilayer microstructure.After solution treatment,the tensile strength and elongation of the samples increased,while the yield strength decreased.After solution treatment for 30 min,the elongation of the samples increased by 54.65%.After solution treatment for 60 min,the high temperature tensile strength of the samples increased by2.9%.After solution treatment,the thermal corrosion resistance of the longitudinal section of the single-channel multilayer sample is improved,and the thermal corrosion resistance of the sample is improved by about 14.9%after solution treatment at1150℃/30 min.With the increase of solution time,the thermal corrosion resistance of the sample decreases.Compared with interlayer laser remelting,solution treatment can eliminate dendrite segregation and reduce the microhardness,while the tensile strength and yield strength are not significantly improved.