Measurement and Modeling of Hydrogen Environment-Assisted Cracking in a Ni-Cu-Al-Ti Superalloy

This research improves H decohesion mechanism-based modeling of intergranular stress corrosion cracking in a Ni-Cu superalloy, Monel K-500. New cracking data plus improved model parameters lead to accurate predictions of the cathodic potential dependencies of K-TH and H diffusion-limited da/dt(II) for Monel K-500 under slow-rising K in 0.6 M NaCl solution. Experiments and modeling demonstrate that IGSCC is eliminated for applied potentials more positive than a critical level between -900 and -840 mV(SCE), but slow-subcritical cracking persists by a microvoid-based mechanism. (C) The Minerals, Metals & Materials Society and ASM International 2016