Embrittlement of B2 iron aluminide by water vapor and by hydrogen

The kinetics of embrittlement of a B2 iron aluminide in air were determined by measuring subcritical crack velocities under constant loading conditions and by measuring the strain rate dependence of the ductility. Correlative studies of embrittlement by internal hydrogen were carried out on cathodically charged samples, and the rates of ductility recovery were measured by baking the samples. The results of the hydrogen experiments are employed to consider whether subcritical cracking in air at the measured rates can be supported by hydrogen penetrating ahead of the advancing crack. © 1994 The Minerals, Metals and Materials Society, and ASM International