Dynamic deformation of hydrogen charged austenitic-ferritic steels: Hydrogen trapping mechanisms, and simulations

Abstract

The influence of hydrogen on austenitic-ferritic (duplex) stainless steels is studied by dynamic experiments supported by lattice defects' energy with hydrogen. The susceptibility of steels to hydrogen fracture mechanism is directly related to the interaction between traps (defects) and hydrogen; therefore, it is being affected the most by the deformation process. The purpose of this paper is to study and analyze the applicability of hydrogen embrittlement in lean duplex stainless steel (LDS) at high strain rate (∼105 s−1) and high dynamic pressure (above 8 GPa). This article reviews hydrogen defects' energy to activate hydrogen fracture mechanisms, in LDS alloys, in response to deformation at strain rates of 10−7 s−1, and compares these results to new experiments at high strain rates of 105 s−1. We support these results by post-microstructural observations, after dynamic experiments, and measurements of trapping energy levels using thermal desorption measurements (TDS) analyzed by Lee and Lee's model. Simulations for dynamic experiments were applied. From these results, we refer for the first time to the invalidity of the hydrogen fracture mechanism at high strain rate (105 s−1) and high dynamic pressures (P ≥ 8 GPa).