Hydrogen environment embrittlement of solution treated Fe-Cr-Ni super alloys

The results indicate that hydrogen embrittlement of ternary Fe-Cr-Ni alloys with Cr contents between 15 and 20 wt% and Ni contents greater than 40 wt% is strongly related to respective microstructural features. It appears that alloys with a pure austenitic microstructure show no degradation in tensile ductility under the given test conditions while microstructures with carbide precipitates on the grain boundaries show ductile intergranular fracture based on grain boundary decohesion. A binary 20Cr-80Ni alloy showed severe degradation in tensile ductility possibly due to the superposition of hydrogen enhanced planar slip and inherent planar slip.