The effect of single grain boundaries on the Portevin-LeChâtelier effect was investigated by depth-sensing Vickers indentation. The experiments were carried out under load control. Independently appearing Portevin-LeChâtelier bands were observed in the plastic volume, and were attributed to hindered dislocation motion through the grain boundary. A hardening effect of the grain boundary, and a release of piled-up dislocations, were also observed. This transient effect was manifested by a dynamic over-shoot in the hardness decrease. This was a consequence of the Portevin-LeChâtelier effect, as it was also reproduced by a phenomenological numerical model.

Effect of Grain Boundaries on PLC Plastic Instabilities. Z.Kovács, D.Fátay, K.Nyilas, J.Lendvai: Journal of Engineering Materials and Technology, 2002, 124[1], 23-6