Effect of Grain Boundary Carbide on Hydrogen Embrittlement in Stable Austenitic Stainless Steels

The effect of grain boundary precipitates on hydrogen embrittlement was investigated with a stable austenitic stainless steel, Fe-20Cr-11Ni-5Mn-2Mo-0.5Si-0.3N-0.1C (wt.%). The steels were aged to form M23C6 along the grain boundaries and electrochemically charged with hydrogen. Based on the fractography and silver decoration results, it was found that hydrogen seemed to be concentrated at M23C6/austenite interfaces, and have promoted crack initiation and propagation. Accordingly, hydrogen-induced ductility loss was intensified in the aged alloys.