Effects of Different Magnetron Sputtering Processes on Properties of SLM-processed Inconel 718 Alloy

CrN_x thin films were deposited on SLM formed Inconel 718 substrate by plasma enhanced magnetron sputtering with different nitrogen flow rates. The phase composition, cross-sectional morphology, mechanical properties and corrosion resistance in 3.5% NaCl solution of the samples were characterized by XRD, SEM, nanoindenter, friction and wear tester and electrochemical workstation. The effects of different magnetron sputtering processes on the surface mechanical properties and corrosion resistance of SLM formed Inconel 718 alloy were mainly discussed to provide a process reference for improving the surface performance of parts prepared by SLM technology. The results show that after 55 mL/min nitrogen flow treatment, the surface hardness of the sample is 20.50 GPa, the elastic modulus is 292.30 GPa, the wear loss is 4.69×10^-4mm³,and the friction coefficient is 0.12. Compared with the untreated sample, the sample after high nitrogen flow treatment exhibits excellent mechanical properties and wear resistance. In 3.5 wt% NaCl solution, the corrosion potential of the sample treated with 40 mL/min nitrogen flow rate is -23.8 m V, and that of the sample treated with 55 mL/min nitrogen flow rate is -32.8 mV, both are higher than-411.5 mV of the untreated sample. The surface properties of SLM formed Inconel 718 alloy can be significantly improved by using different nitrogen flow rates, which can better meet the requirements of service performance.