Critical assessment of the fatigue performance of additively manufactured Ti–6Al–4V and perspective for future research

• Review of AM Ti–6Al–4V fatigue performance.
• Effect of surface treatment on AM fatigue performance.
• Effect of heat treatment on AM fatigue performance.

To realize the potential benefits of additive manufacturing technology in airframe and ground vehicle applications, the fatigue performance of load bearing additively manufactured materials must be understood. Due to the novelty of this rapidly developing technology, a very limited, yet swiftly evolving literature exists on the topic. Motivated by these two points, we have attempted to catalog and analyze the published fatigue performance data of an additively manufactured alloy of significant technological interest, Ti–6Al–4V. Focusing on uniaxial fatigue performance, we compare to traditionally manufactured Ti–6Al–4V, discussing failure mechanisms, defects, microstructure, and processing parameters. We then attempt to identify key knowledge gaps that must be addressed before AM technology can safely and effectively be employed in critical load bearing applications.