Research On The Process,Microstructure And Properties Of Nickel-Based Superalloy Fabricated By Plasma Arc Additive Manufacturing

Nickel-based superalloys are widely used in aerospace,petrochemical and marine engineering fields due to their merits of excellent microstructure stability,high temperature oxidation resistance and high temperature strength.However,the difficulty in the forming process of the complicated structural components of the nickel-based superalloys has been one of the key technologies to be solved in this field.In recent years,with the development of additive manufacturing(AM)technology,a great effrots have been made to adopt the AM in the prototyping manufacturing of the complicated structral componets of nickel-based superalloy.Through structural optimization design and process flexible control,the complicated structural parts based on nickel-based superalloys can be realized by single-use near-net shape.In this paper,Inconel690 alloy wire was usedto investgate the processes of plasma arc additive manufacturing technology on the fabrication of the multilayer thin-walled componet.The relationship between the parameters(such as,power P,scanning speed V,wire feeding speed F)of the additive manufacturing process and the macroscopic morphlogies,the parameters and the microstructure,the parameters and the mechanical properties are investigated by process test,microstrucutre characterization,mechanical properties test and simulation of prediction methods,the best process parameters of plasma arc additive manufacturing to produce the Inconel690 alloy are obtained.Specific research contents and research results are as follows:The influence of single-pass single-layer additive manufacturing process parameters on the macroscopic morphology of the sedimentary layer of the sample shown that as the wire feeding angle(?)is less than 45°,the heating power(P)is higher than 1.6 KW and the wire feeding speed(F)is less than 3.0 m/min,macroscopic morphology of the sedimentary layer is fine and none defects are generated,the scanning speed(V)has less effect on the mrophologies of deposited layer.The optimum process parameters of additive manufacturing for thin-walled parts were determined to be as follow: feeding angle is equal to 0°,the heating power(P)is 1.6 KW,the wire feeding speed(F)is range from 2.4 to 3.0 m/min and the scanning speed is equal to 3.0 mm/s.The sample produced at the optimun process parameters as mentiond above is composed of the matrix(? phase)and the precipitates of MC(Nb C)phase and the(Nb,Ti)(C,N)phase.The ultimate tensile strength and the elongation to failure of the sample is 640 MPa and 42% respectively.Heat treatment process test on multi-layer thin-walled parts shown that the ultimate tensile strength of sample increased with the increase of the temperature of heat treatment and then it will decrease.The ultimate tensile strenth reached a maximum of 740 MPa as the temperature of heat treatment of 980?.BP artificial neural network technology,a three-layer artificial neural network model of the process parameters of the plasma arc additive manufacturing and the mechanical properties of Inconel690 alloy was constructed.Through the simulation and data training of the model,the influence of the main process parameters of the additive manufacturing on the mechanical properties of the alloy was accurately predicted.