The Effect of Build Orientation on Mechanical Properties of Selective Laser Melted Inconel 718

The production of components via selective laser melting (SLM) metal additive manufacturing results in microstructures unique to the process and highly dependent on laser processing parameters and orientation of part geometry relative to the build direction. This study looks at the variation in tensile properties of SLM Inconel 718 at varying angles with respect to build direction. Horizontal (0°), vertical (90°), and angled (45°) ASTM E8 tensile specimen were built to near-net shape, HIP and heat treated, and tensile tested at room and elevated (650°C) temperature. Orientation dependence of mechanical properties was observed, with vertical samples having the lowest strength and highest elongation, and the horizontal samples having the highest strength and lowest elongation. Optical, SEM, and EBSD analysis were conducted to probe for microstructure variation that could be the cause of this mechanical variation. Analysis of pole figures and grain maps suggests a preferred grain texture and twinning orientation in the specimen aligning with the build direction, which may contribute to the anisotropic enhancement in ductility observed.