3D-Printing of Inconel-625 Superalloy by Selective Laser Melting

Additive manufacturing as the process of manufacturing engineering parts in a layer by layer manner, has been used for a few decades. Between different additive methods, selective laser melting is one of the most promising techniques. This is due to the high manufacturing quality specially when fabricating metallic compounds. Among different metallic compounds Inconel 625 has one of the most compatible alloys with additive processes due to the high strength properties, excellent weldability. Achieving properties in as built parts comparable to that of the conventionally manufactured counterparts, has been a challenge. These samples were built with linear heat input of 0.125, 0.150 and 0.175 joules per millimeter. Data suggested and increase in average grain size with increase in applied heat input. Also due to the different heating cycles specimen built with different heat input experience, grain structure and elements distribution in the specimen has changed. Also variation in heat input didn’t cause significant difference in mechanical properties of the samples; however, they have exhibited higher mechanical properties compared to casted counterparts and shown properties comparable to that of the wrought parts. Manufactured parts had significantly higher hardness compared to conventionally manufactured counterparts even that of the wrought ones. Based on optical microscopy studies, higher mechanical properties of the specimen can be considered a result of the fine grain size of the fabricated parts.