Enhanced Assessment of the Fatigue Behavior and Damage Tolerance of Additively Manufactured Metals and Components

Abstract

Layer-by-layer manufacturing of complex and lightweight structures is possible with additive manufacturing (AM) using powder bed fusion (PBF). Due to the fine microstructures generated by the high cooling rates, the tensile strength is improved, whereas the fatigue strength is comparable or even reduced. This is due to the presence of process-induced defects formulated during the manufacturing process in combination with the increased notch and mean stress sensitivity of high-strength metals. The damage evolution, including crack initiation and propagation, may be determined concerning fatigue stress and lifetime using modern measurement techniques before, during, and after fatigue testing. This will lead to a deeper understanding of the characterization of AM metals and how different variants and parameters can affect the fatigue behavior. Through this paper, three different AM alloys (AlSi10Mg, 316L and TNM-B1) are studied with respect to how the process-induced defects can affect the fatigue lifetime and resulting scattering and how the fatigue damage tolerance can be uniformly represented.