Influence of deposition orientation on fatigue response of LENS™ processed Ti6Al4V.

Understanding processing-property relationships for directed-energy-deposition (DED) parts remains a major roadblock to widespread process implementation. Herein we investigate the effect of scanning-strategy and testing-orientation on the fatigue response of as-printed Ti6Al4V components. At ~10 cycles, samples tested in the build-direction exhibited ~ 45% decrease in fatigue strength relative to the horizontally-tested samples, owing to higher overall porosity and the testing orientation relative to residual pores. Samples failing <10 cycles demonstrated tortuous surfaces, whereas samples enduring >10 cycles exhibited smoother-surfaces. Our results indicate that DED-produced parts can exhibit directionally-dependent fatigue performance, and print-strategy must be taken into consideration for dynamic-loading applications.