The influence of building orientation of additively produced samples on their mechanical properties

Abstract

Direct metal laser sintering (DMLS) produces parts from metal powders using the energy of the laser beam to promote sintering in an inert and thermally controlled chamber environment. Many factors influence the resulting mechanical properties of each part. One of these parameters is the direction in which the part is built. The paper addresses the behavior of 3D-printed maraging steel MS1 in uniaxial tensile tests, where the effect of specimen orientation on the modulus of elasticity as well as other mechanical properties was investigated. The morphology of the fracture surfaces was also evaluated using scanning electron microscopy. Standard specimens were fabricated using DMLS technology in five different orientations, with ten specimen pieces produced in each direction. After 3D printing, the specimens were heat treated to remove residual stresses and machined to final dimensions after removal from the building platform. The measured values were statistically processed and the mechanical properties were evaluated. The tests showed that the orientation of the sample during its production has an effect on the mechanical properties. The comparison of the results with the tensile properties stated by the manufacturer of the steel powder in the data sheet confirmed the values in the declared range. Numerical analysis realized based on measured data implemented to the ANSYS software confirmed experimentally obtained value for ultimate tensile stress. It could be also stated that the morphology of fracture surfaces in most samples was characterized by ductile damage with a pitting effect.