%0 journal article
%@ 0921-5093
%A Winzer, N.,Atrens, A.,Dietzel, W.,Song, G.,Kainer, K.U.
%D 2007
%J Materials Science and Engineering  A
%N 1-2
%P 18-31 
%R doi:10.1016/j.msea.2007.03.020
%T Evaluation of the Delayed Hydride Cracking Mechanism for Transgranular Stress Corrosion Cracking of Magnesium Alloys
%U https://doi.org/10.1016/j.msea.2007.03.020
1-2 
%X This paper evaluates the important elements of delayed hydride cracking (DHC) for transgranular stress corrosion cracking (TGSCC) of Mg alloys. A DHC model was formulated with the following components: (i) transient H diffusion towards the crack tip driven by stress and H concentration gradients; (ii) hydride precipitation when the H solvus is exceeded; and (iii) crack propagation through the extent of the hydride,when it reaches a critical size of ~0.8 µm. The stress corrosion crack velocity, Vc, was calculated from the time for the hydride to reach the critical size. The model was,implemented using a finite element script developed in MATLAB. The input parameters were chosen, based on the information available, to determine the highest possible value for Vc. Values for Vc of ~10-7 m/s were predicted by this DHC model.,These predictions are consistent with measured values for Vc for Mg alloys in distilled water but cannot explain values for Vc of ~10-4 m/s measured in other aqueous environments. Insights for understanding Mg TGSCC are drawn. A key outcome is,that the assumed initial condition for the DHC models is unlikely to be correct. During steady state stress corrosion crack propagation of Mg in aqueous solutions, a high dynamic hydrogen concentration would be expected to build up immediately,behind the crack tip. Stress corrosion crack velocities ~ 10-4 m/s, typical for Mg alloys in aqueous solutions, might be predicted using a DHC model for Mg based on the time to reach a critical hydride size in steady state, with a significant residual,hydrogen concentration from the previous crack advance step.