Influence of Strain Rate on the Strain Hardening Behavior of a Lean Duplex Stainless Steel

The aim of this study was to examine how strain rate influences the compressive strain‐hardening behavior of a lean duplex stainless steel LDX 2101. Microstructural analysis using electron backscatter diffraction (EBSD) revealed a strain‐induced austenite‐to‐martensite transformation. The yield strength of the alloy increased with increasing strain rate, whereas its hardening capacity showed a slight decrease. This trend suggests that at higher strain rates, dislocation slip was not the dominant deformation mode in the FCC austenite phase of LDX 2101. Despite these changes, the strain‐hardening exponents determined from the four constitutive models of Ludwik, Hollomon, Swift, and Afrin et al. remained largely insensitive to strain rate. Strain‐rate sensitivity was assessed using both the common power‐law method and Lindholm approach, with the latter providing a more sensitive characterization due to its consistently higher sensitivity values. Additionally, LDX 2101 exhibited Stage III hardening followed by Stage IV hardening, with the highest strain hardening rate observed at the lowest applied strain rate.