Cyclic Plastic Material Behavior of Novel Austenitic (C + N) Steel Additively Manufactured by PBF‐LB/M

The newly introduced high manganese high strength (C + N) steel Printdur HSA was developed for the additive manufacturing process PBF-LB/M. It consists of a fully austenitic grain structure. This study aims to evaluate the cyclic plastic material behavior of this (C + N) steel. Therefore, tensile tests and strain-controlled low-cycle fatigue tests were conducted. Strain amplitudes between 0.5% and 3.0% were applied. Furthermore, the microstructure was examined. In particular, electron backscatter diffraction and scanning transmission electron microscopy were applied. For all strain amplitudes, a general softening behavior is visible. The strain amplitude of 0.5% results in primary hardening within the first 30 cycles. Therefore, a dependency of the cyclic material behavior on the applied strain amplitude can be assumed. This behavior correlates with the investigated characteristics of the microstructure. The observed mechanical behavior is linked to microstructural mechanisms, including dislocation rearrangement, persistent slip band formation, and grain boundary interactions. A comparison with conventionally used PBF-LB/M/316L highlights the superior static mechanical and fatigue performance of Printdur HSA. These results improve the understanding of the cyclic deformation mechanisms of this material and support its structural application under fatigue loading at high strains.