Microstructural Characterization and Study of Hydrogen Embrittlement in Duplex Stainless Steels

Abstract

Hydrogen embrittlement (HE) remains a critical challenge in the deployment of duplex stainless steels (DSS) for energy, maritime and chemical processing applications. The duplex stainless Steel having a unique dual-phase microstructure of austenite and ferrite, which offers high strength and corrosion resistance, thereby making it a suitable candidate for use in harsh environments. However, exposure to environments with a high hydrogen content can severely reduce its mechanical performance, leading to premature and often catastrophic failure. This study examines how hydrogen charging affects the tensile behaviour and fracture properties of DSS using the slow strain rate testing (SSRT), the In-situ SSRT under electrochemical hydrogen charging, and the thermal desorption analysis (TDA). Samples were examined for microstructural characteristics using the scanning electron microscope (SEM) in order to evaluate the phase balance and fracture modes. It was discovered that with hydrogen charging, there was a noticeable loss in strength and ductility, a distinct change from ductile to brittle fracture modes, and hydrogen trapping behaviour that is associated with certain microstructural characteristics. These result offers a useful understanding into how hydrogen interacts with DSS and contribute towards developing mitigation plans for the safer and more reliable use of DSS in hydrogen service applications.