Directional and notch effects on the fatigue behavior of as-built DMLS Ti6Al4V

- A novel fatigue test method using miniature specimens is presented and validated.
- The fatigue behavior of SLM Ti6Al4V in as-built and notched conditions published is quantified.
- The present notch fatigue factors are coherent with recently data.
- New evidence of the notch fatigue behavior of SLM metals is presented.
- The SLM process conditions introduce multiple notch fatigue factors.

The metal additive manufacturing technology produces components of any geometrical complexity directly from a computer model. Full exploitation of metal AM technology may result in parts that can be lighter in weight, cheaper to produce, and have complex geometries that are difficult or impossible to produce with conventional methods. Two aspects significantly affecting the fatigue behavior of DMLS Ti6Al4V are investigated: (i) the as-built surface condition, which is known to introduce a significant knock-down factor in fatigue with respect to the machined condition, and (ii) the presence of a geometrical notch, which affect conventional materials but has not yet been studied in metal AM parts. After the preliminary determination of the reference unnotched fatigue response, the notch fatigue behavior of as-built DMLS Ti6Al4V specimens is determined. Four different notch fatigue factors are estimated including the influence of notch direction with respect to build direction and the notch fabrication conditions.