EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

The mechanical properties, such as low cycle fatigue resistance, are tightly connected to the character of microstructure. Various processing techniques result in distinctively different microstructures which directly affect cyclic behaviour and fatigue life. This study presents a comparison of conventionally processed metastable austenitic stainless steel 304L with its SLM-processed counterpart in terms of cyclic behaviour, fatigue life and surface relief evolution. Cyclic stress-strain response of conventional material exhibited at various total strain amplitude exhibited a typical sequence of initial cyclic hardening followed by mild cyclic softening and secondary cyclic hardening which extend depends on the volume fraction of deformation-induced martensite. SLM-processed material exhibited different cyclic behaviour with a more pronounced softening stage and reduced secondary cyclic hardening. The reasons for different cyclic stress-strain response and reduced extend of martensitic transformation will be discussed and addressed also with respect to carried out surface relief evolution observations, ECCI imaging and EBSD mapping.

This research is performed within the frame of the project 19-25591Y funded by Czech Science Foundation.