Rotating Scan Strategy Induced Anisotropic Microstructural and Mechanical Behavior of Selective Laser Melted Materials and Their Reduction by Heat Treatments

Choosing a properly optimized rotating scan strategy during the selective laser melting (SLM) process is essential to reduce residual stresses and thus obtain homogeneous properties. Surprisingly, anisotropic material properties are found in several materials that built with often applied stripes of Electro-Optical Systems (EOS) because avoids possible interactions beam by-products therefore excludes range scanning directions. Herein, alloys Hastelloy X, Inconel 718, stainless steel 316L investigated. Vertically specimens cylindrical gauge geometry show an oval deformation tensile testing, indicating mechanical anisotropy horizontal x- y-direction. Tensile tests along y-direction reveal deviation yield strength 7% for X. Analyses microstructures differences grain morphology, size, texture all three coordinate planes materials. This behavior can be explained by detailed study calculated Schmid factors. Heat treatments textural due recrystallization grains but requires annealing at sufficiently high temperatures long times.