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

Issue Section:
Technical Papers
Keywords:
Portevin-Le Chatelier effect, grain boundaries, dislocation drag, dislocation pile-ups, indentation, Vickers hardness
Topics:
Grain boundaries, Stress, Dislocations
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 by ASME
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