Evaluation of the Corrosion Behavior of Inconel 625 Superalloy Made by SLM Method
Subject Areas : Journal of Environmental Friendly MaterialsLamyaa Idkhayyil Mahood ALLKASHEESH 1 , mohammad razazi boroujeni 2
1 - MSc, Department of Materials Engineering and Metallurgy, South Tehran Branch, Islamic Azad University, Tehran, Iran
2 - استادیار، گروه مهندسی مواد، واحد لنجان، دانشگاه آزاد اسلامی، اصفهان، ایران
Keywords: Heat Treatment, Inconel 625, Selective Laser Melting, Corrosion,
Abstract :
The purpose of this research is to investigate the corrosion resistance of Inconel 625 alloy produced by selective laser melting after heat treatment and surface treatment. For this purpose, the samples produced with the help of a Selective Laser Melting Machine (SLM) were prepared in four modes of the prototype (without further treatment), heat treated, surface treated, and finally heat treatment and consecutive surface treatment. To perform heat treatment, the combined cycle of annealing and aging was used. In the surface treatment, the shot pinning method was used for 30 minutes using steel balls. X-ray diffraction analysis was performed to determine the phase of the samples. Peaks of the primary γphase, nickel carbide, and molybdenum were revealed in the heat-treated samples. In the following, the samples were electrochemically evaluated in 3.5 wt.% NaCl medium with potentiodynamic polarization tests and Electrochemical Impedance Spectroscopy (EIS). The results showed that the SLM-HT sample has the most positive corrosion potential and the lowest corrosion current density, while the SLM 625 sample shows the most negative corrosion potential and the highest corrosion current density. Heat treatment improved both thermodynamic behavior and kinetic behavior, but the surface treatment had little effect on improving corrosion. Also, the results of the EIS test showed that the HT-625 sample had the highest polarization resistance and the lowest charge accumulation (capacitance),while the 625 sample showed the lowest charge transfer/polarization resistance and the highest capacitance.
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