As-built sharp notch geometry and fatigue performance of DMLS Ti6Al4V

Metal parts obtained by the layer-wise selective melting of a powder bed are characterized by surfaces that are considerably rougher than conventionally machined parts. Application of lightweight design tools results in complex part geometries with notches, reentrant corners, internal surfaces that are difficult to inspect and whose surface finish may not be improved. To efficiently investigate the fatigue response of as-built DMLS Ti6Al4V in the presence of as-built notches a miniature specimen approach is adopted. Sets of directional mini specimens were manufactured with the long axis parallel and perpendicular to the build direction and heat treated. The sharp notched bar geometry is subjected to cyclic bending. The interaction of directional notch generation, surface quality and geometrical accuracy on the notch fatigue behavior is quantified and discussed.