Influence of surface orientation and segmentation on the notch fatigue behavior of as-built DMLS Ti6Al4V

Design and qualification of load-bearing metal parts produced by the additive manufacturing technology is a critical issue. Such metal parts are complex in geometry with notches that are critical locations under fatigue loading. Notch surfaces are typically in the as-built state because post-fabrication surface finishing is not a viable approach in most applications. Here fatigue experiments using notched specimens produced according to different orientations with respect to build direction are presented and used to discuss the notch fatigue behavior of DMLS Ti6Al4V. Notch fatigue factors depend on the process itself and on fabrication details such as up-skin versus down-skin surface orientation, stair-stepping of the notch surface due to the layer-by-layer segmentation and intrinsic as-built surface roughness.