Fatigue Crack Growth behavior of Additively Manufactured 17-4 PH Stainless Steel: Effects of thickness and surface condition

Additive Manufacturing revolutionized the field of manufacturing by enabling the production of complex geometries with greater design freedom. However, the use of these components for structural applications depends on a proper understanding of their mechanical behavior, which may differ significantly from that of traditionally manufactured counterparts. This study aims to investigate the Fatigue Crack Growth behavior of 17-4 Precipitation Hardening Stainless Steel obtained via Laser Powder Bed Fusion. Four sets of Compact Tensile specimens were tested to investigate the fatigue crack growth properties of the material analyzed. Different procedures can be considered for this kind of tests; in the present study the constant amplitude procedure was considered. The objective of the tests was to characterize the Paris regime and assess the influence of thickness and surface condition on the Fatigue Crack Growth properties. In order to gain insights into the mechanisms of crack growth, macro-graphic observations and Scanning Electron Microscope analysis were carried out to study the microstructure and the fracture surface. The results of these analyses revealed no significant differences in the behavior among the specimens of different sets. This finding was attributed to the low presence of defects and the isotropy of the material, resulting from the CA-H1025 heat treatment to which the specimens were subjected.