Hydrogen Embrittlement in a 2101 Lean Duplex Stainless Steel

Duplex Stainless Steels (DSSs) are an attractive class of materials characterized by a strong corrosion resistance in many aggressive environments. Thanks to the high mechanical performances, DSSs are widely used for many applications in petrochemical industry, chemical and nuclear plants, marine environment, desalination etc.
Among the DSSs critical aspects concerning the embrittlement process, it is possible to remember the steel sensitization and the hydrogen embrittlement.
The sensitization of the DSSs is due to the peculiar chemical composition of these grades which, at high temperature, are susceptible to carbide, nitrides and second phases precipitation processes mainly at grains boundary and in the ferritic grains. The hydrogen embrittlement process is strongly influenced by the duplex (austenitic-ferritic) microstructure and by the loading conditions.
In this work a rolled lean ferritic-austenitic DSS (2101) has been investigated in order to analyze the hydrogen embrittlement mechanisms by means of slow strain rate tensile tests, considering the steel after different heat treatments. The damaging micromechanisms have been investigated by means of the scanning electron microscope observations on the fracture surfaces.