On the fatigue notch sensitivity of Ti6Al4V specimens with α+β
microstructure produced by laser powder bed fusion
Laser powder bed fusion (L-PBF) is an additive manufacturing (AM)
process which offers several advantages over conventional manufacturing
techniques, including material savings and design possibilities. For
these reasons several industrial sectors such as biomedical, aerospace
and automotive, are considering L-PBF for customized parts production.
Among the processable material palette, Ti6Al4V gained increasing
interest due to the high specific strength, and stiffness, and excellent
bio-compatibility, and corrosion resistance. However, to include L-PBF
Ti6Al4V parts in load bearing applications it is important to properly
understand the mechanical properties of AM’ed materials with a specific
focus on fatigue behaviour. In this study the fatigue notch sensitivity
of Ti6Al4V L-PBF manufactured specimens is investigated in depth.
Samples with different notches were subjected to stress relieving heat
treatment to generate a fine α+β microstructure. The results were used
to define a relation between the perturbed stress field generated by the
geometrical discontinuity, the microstructure size and the notch
sensitivity. Moreover, the critical distance has been calculated using
the theory of critical distance formulated with the line method (LM).
The estimated value were adopted to predict fatigue properties of
notched components with different notch radii.