A holistic review on fatigue properties of additively manufactured metals

Additive manufacturing (AM) technology is undergoing rapid development as an advanced technique for fabricating light-weight and complex-shape metallic parts with acceptable strength and fatigue performance. A number of studies have indicated that the strength or other mechanical properties of AM metals are comparable or even superior to that of conventionally manufactured metals, but the fatigue performance is still a thorny problem for AM counterparts under the cyclic or fatigue loading. There yet lacks a holistic overview on the fatigue performance and data of AM metals. Herein this article contributes to reviewing the state-of-art published data on the fatigue properties (S–N data and fatigue crack growth data) of AM metals. Further, the fatigue properties of AM metallic materials that involve titanium-, aluminium-, nickel-, magnesium-based alloys, stainless steel, and high entropy alloys, are systematically overviewed. Summary figures and tables for the published data on fatigue properties are presented for the above metals, the AM techniques, and the influencing factors (manufacturing parameters, e.g., built orientation, processing parameter, and post-processing). The fatigue performance and main factors affecting the fatigue behaviour of AM metals are finally compared and critically analysed, thus potentially providing valuable guidance for improving the fatigue performance of AM metals.