Tensile anisotropy of powder bed fusion steel 316L: A practical study on the effect of build orientation

Abstract

This study investigated the tensile anisotropy of steel 316L fabricated via laser powder bed fusion (L-PBF), built at different orientations. Tensile tests were performed on as-built L-PBF specimens produced at 0°, 15°, 30°, 45°, 60° and 90° angles. The yield strength, ultimate tensile strength and elasticity modulus experienced a decrease with an increasing build angle. Conversely, elongation at fracture increased as the build angle increased. The Elasticity modulus was found to be substantially lower than the nominal values reported in the material data sheet of the L-PBF equipment manufacturer. Fractography performed via Scanning Electron Microscopy (SEM) has found indications of porosity and lack of fusion that may have contributed to lower Elasticity modulus and an overall impacted mechanical performance. A complementary powder quality analysis has offered further insights on this and provided indications on the powder recycling impact.