On the Determination of Fatigue Properties of Ti6Al4V Produced by Selective Laser Melting

This paper provides new insights into the fatigue properties of Selective Laser Molten components made from Ti6Al4V powder particles. The SLM-process parameters are optimized and high quality SLM-parts with a relative density of 99.7% are produced. Uniaxial fatigue experiments are then performed on notched and unnotched specimens and the endurance limits are determined using the staircase method and the theory of Dixon and Mood. The presented results indicate inferior fatigue strength in comparison with conventionally produced components from Ti6Al4V. Microstructural analysis shows that this is mainly due to the anisotropy in the microstructure and the weak grain boundaries between epitaxial grains. However, the failure mechanism is consistant leading to low statistical scatter in the fatigue data. Furthermore, the critical volume method and the critical distance theory have proven to be accurate and efficient design tools to account for the notch-effect in SLM-Ti6Al4V.