The role of grain boundary solutes and structure on the yielding and intergranular cracking of iron

Abstract

The effect of interstitial solute concentration and partitioning, and grain boundary extrinsic structure on the magnitude of the Petch parameters and frequency of hydrogen-induced intergranular cracking was systematically investigated in both decarburized iron and Fe-0.15 pct Ti. It was established that grain boundary interstitial solutes increase the value of the petch slope and the presence of these solutes in the lattice increases the value of the “friction” stress. Their presence in the grain boundary also increases the frequency of intergranular cracking. This is not true for extrinsic grain boundary ledges, whose presence does not appear to effect either the Petch parameters or hydrogen-induced cracking. The observed results were rationalized by the behavior of interstitial solute complexes at the boundary and the ability of such complexes to react with hydrogen.