The Hydrogen Induced Mechanical Degradation of Duplex Stainless Steel

Abstract

This study considers the interaction between duplex stainless steel type 2205 and electrochemically charged hydrogen. Duplex stainless steels combine the mechanical properties of ferrite with the corrosion resistance of austenite and are widely used in many industrial applications. However, they are susceptible to hydrogen embrittlement. In this work, the steel microstructure is first characterized by scanning and transmission electron microscopy, X-ray diffraction, and electron backscatter diffraction. Subsequently, melt extraction is done to determine the amount of hydrogen charged into the material, while in situ hydrogen charged tensile tests are combined with a fractography analysis to evaluate the effect of hydrogen on the mechanical behavior. The material displays a rather significant ductility loss of about 26% as a result of the applied hydrogen charging. Melt extraction identifies the increased hydrogen content in the steel microstructure (up to 50 wppm). Moreover, the hydrogen embrittled regions correspond well to the hydrogen diffusion penetration depth from the edges onwards. These cleavage brittle areas are observed up to the theoretical hydrogen diffusion distance, demonstrating the hydrogen embrittlement effect.