Study On The Inconel 625 Alloy Prepared By Laser Melting Deposition Using Abrasive-Assisted Jet Electrochemical Machining

Laser melting deposition(LMD)is commonly used for additive forming of nickel-based superalloy.Aiming at the problems of deformation,surface defects and forming precision in the process of laser melting deposition of nickel-based superalloy,this paper proposes the LMD-jet electrochemical machining(JECM)hybrid fabrication,and designs a new abrasive-assisted JECM device.The main research contents are as follows:(1)Proposed the LMD-JECM hybrid fabrication,explaining the process of the LMD-JECM hybrid fabrication,analyzing the necessary equipment for the LMD-JECM hybrid fabrication.The final part was processed by the combination of the additive manufacturing process of LMD and the reduction process of JECM.(2)Design an abrasive-assisted JECM test system.The existing JECM machine can not directly process the nickel-based superalloy LMDed sample,so the f abrasive-assisted JECM device is designed.Compared with the traditional JECM machine,the abrasive-assisted JECM test system effectively improves the surface quality after processing.The abrasive-assisted JECM system is built based on a hardware system with the STM32 development platform and a software system with μC/OS-II.(3)Analyze the solidification process of melting pool and the internal convection mechanism,deducing the deformation mechanism of laser melting deposition sample,and explaining the processing mechanism of LMDed sample of nickel-based superalloy by the abrasive-assisted JECM device.(4)Study the effect of different processing times on the processing quality.Tests show that the surface oxide layer can be completely removed after 90 cycles of processing,while the soft brush head can effectively remove the electrolysis products,and the hard grinding head can effectively remove the difficult electrolytic residual particles between the laser melting deposition bead.(5)Study the effect of JECM on the deformation of LMDed samples.The test found that after JECM,the maximum deflection of the LMDed deformation specimen was reduced by 19.5%.Therefore,in the process of laser melting deposition,when deformation becomes,the JECM can be used to remove a part of the deposited metal,thereby reducing the deformation that has occurred,thereby reducing the probability of scrapping the parts.(6)The effects of powder feeding rate and overlapping rate on the microstructure and microhardness of LMDed samples were studied by the LMD-JECM hybrid fabrication test system.The experiment shows that the powder feeding rate has little effect on the microstructure of the LMDed sample,while the overlapping rate has a great influence on the microstructure of the laser melt-deposited sample.The effect of the powder feeding rate and the overlapping rate on the microhardness of the LMDed samples is almost the same.