Effect of Scan Direction on Tensile properties and Fractography of Laser Additive Manufactured Maraging Steel

Abstract

Laser additive manufacturing (LAM) is the process used to fabricate near net shape from metallic powders. A major challenge with LAM fabricated parts is the materials performance to achieve required mechanical properties. This work presents the fabrication of 18% Ni Maraging steel 300 (MS) using a LAM process by adopting two scan direction (bi-directional). The scan directions are selected in two perpendicular directions, one is parallel to the loading axis of the tensile specimen (0°) and another is in perpendicular direction to the loading axis of the tensile specimen (90°). Tensile properties and its fractography are investigated to analyse the scan direction effect due to the variation in thermal history. Further, to analyse the defect and pores in the fractured surface, scanning electron microscopy is used. The tensile properties of 90° scan direction are found to be higher owing to the nucleation and micro-void coalescence. This work facilitates to provide a better understanding of the selection of scan direction patterns for fabrication of better quality MS parts using the DMLS AM process.