Preprint for: SEM-DIC comparative study of plastic deformation evolution in AISI 304L fabricated by two different methods

With increasing demands on the materials performance, new production methods are pursued, such as additive manufacturing (AM), which are generally leading to complex internal structures. Therefore, various non-destructive in-situ methods, for example digital image correlation (DIC), have been developed for deeper understanding of the processing – microstructure – properties relationship. Within this work, interrupted tensile test experiments on two AISI 304L steel specimens produced by two different methods, conventional hot-rolled and laser powder bed fusion (LPBF) processed, were performed. The experiment consists of simultaneous observation of the plastic deformation evolution by SEM-DIC method. The evolution of crystallography was followed by EBSD from the same area. Additively, high resolution backscatter electron diffraction (HR EBSD) was performed on selected grains to follow stress distribution and local crystal lattice orientation evolution via Kernel average misorientation (KAM) map. Test interruptions for measurements were done at 1.5, 3, 4.5, and 10 % of total strain. The collected data enabled the identification of active slip systems, which enabled to obtain a comprehensive insight into the plastic deformation evolution. This approach was used for both test specimens to compare the response of differently produced structures of the very same material. Significant heterogeneity of plastic deformation based on the orientation of the crystal lattice can be observed within individual grains of the LPBF-processed microstructure. In contrast, in the case of hot-rolled microstructure, the plastic deformation appears more homogeneously distributed.