Revealing relationships between heterogeneous microstructure and strengthening mechanism of austenitic stainless steels fabricated by directed energy deposition (DED)

• DOI: 10.1016/j.jmrt.2021.08.036
• Publication Date: 2021-08-14T06:06:11Z
• Authors: Zhou Yan; Ke Zou; Manping Cheng; Zhipeng Zhou; Lijun Song
• Keywords: Austenitic stainless steel; Recrystallization (geology); Precipitation hardening; Strain hardening exponent; Hardening (computing); Deformation mechanism

The heterogeneous trans-scale structures play important roles in achieving high strength and toughness austenitic stainless steels fabricated by directed energy deposition (DED). In this study, systematic annealing investigations were demonstrated the evolution of such as dislocations, chemical cells, nano-oxides, grains recrystallization behavior. Their effects on yield quantified. experimentally observed as-received annealed samples agrees well with estimated using standard Taylor hardening formulae. dislocation intensity accounted for 200 MPa became main contributor, among which GND type more than 60% total dislocation. Despite development DED steel micro inclusions, synergistic effect deformation twinning pre-existing GND-induced back stress results tensile plasticity. This research helps to better understand interplay between processing, microstructure 316L mechanical properties that are crucial meeting new demands.