Research On The Microstructure And Properties Of Inconel718 Composite Carbon Nanomaterials Deposited By Laser Melting

Inconel718 high-temperature alloy has good comprehensive performance under high temperature conditions and is widely used in aerospace engine parts and wing support parts.The use of laser additive manufacturing to prepare Inconel718 metal parts is currently a hot topic at home and abroad.Based on the laser melting deposition technology,this thesis studies the Inconel718 and carbon nanotubes and graphene composite reinforced additive manufacturing process,performance testing and microstructure strengthening mechanism.The main work and results are as follows:（1）Preparation of Inconel718 single-pass coatings with different laser powers for process optimization selection.The ZEISS Sigma 300 scanning electron microscope and D/MAX-2500 X-ray diffractometer were used to analyze its microstructure and phase composition.The microstructure is mainly columnar crystals and dendrites crystals,the phases are mainly（Ni,Fe）、γ′-Ni₃（Al,Ti）and Fe₃Ni₂.（2）2.5wt.%nickel-plated carbon nanotubes composite Inconel718 material was prepared by planetary ball mill mixing.The hardness,friction and wear,electrochemical corrosion properties of the Inconel718 coatings and nickel-plated carbon nanotube/Inconel718 coatings were analyzed and tested.Tests showed that new phases such as（Fe,C）、C₇₀、Fe₅C₂ were formed.Compared with the Inconel718 coatings,the number and length of cracks in the nickel-plated carbon nanotubes composite coatings were significantly reduced,and the microstructure was more uniform.（3）5wt.%graphene composite Inconel718 material and coatings were prepared.Raman spectroscopy and transmission electron microscopy tests showed that graphene was partially ablated in the coatings,but its unique flaky shape was basically maintained;There are a large number of（Nb,Ti）C precipitates in the composite coatings,and its microstructure is mainlyγ/M₇C₃ eutectic structure,the friction and wear performance is greatly improved.