Inconel 718 (IN718) is a superalloy with excellent corrosion resistance and high temperature stability, giving rise to its popular use in the aerospace industry as well as other high performing applications. This study utilizes the relatively low conductivity of IN718 to focus in on the heat transfer procedures in which occur during the laser powder bed fusion (LPBF) manufacturing process of metals. Cylindrical samples of constant geometry with varying dimensions of thermal supports were fabricated using a compatible IN718 build plate. As thermal support size increased, heat dissipation to the build plate consequently increased. Theoretically, this modification of heat transfer should lead to interesting microstructural changes during solidification. Gas atomized IN718 powders with a D90 value of 46.76 µm were selected for production. Samples were subsequently metallographically characterized to establish any modifications in microstructural development. Density upwards of 99.76% was achieved in all samples with no obvious trend relating to support parameters. Surface roughness of vertically sectioned samples was carried out, with roughness found to vary among samples, generally increasing as size of thermal supports decreased. An associated angular variation was observed at the bottom surface for samples designed to have smaller thermal supports and thus more overhanging area. While melt pool measurements did not convey any variation among samples, FE-SEM exhibited interesting findings in both the XY and XZ planes regarding size of sub-grain cells. While heat conduction to the build plate undoubtedly plays a crucial role in SLM, it remains unclear whether a relationship with cell size exists.
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Master of Science in Materials Science and Engineering (M.S.M.S.E.)
College of Engineering and Computer Science
Materials Science and Engineering
Materials Science & Engineering
Length of Campus-only Access
Masters Thesis (Open Access)
Drobner, Erica, "The Effect of Heat Transfer on Microstructural Development For Inconel718 Nickel-Based Superalloy in Laser Powder Bed Fusion" (2022). Electronic Theses and Dissertations, 2020-. 1195.