Influence of grain size and grain boundaries on the thermal and mechanical behavior of 70/30 brass under electrically-assisted deformation

The influence of grain size and grain boundaries on the thermal and mechanical behavior of 70/30 brass was studied during tension tests in which electric current was applied in conjunction with mechanical deformation. Decreasing grain size was observed to increase Joule heating and increase stress reductions during electrically-assisted deformation. Additionally, a larger decrease in material flow stress was observed in electrically-assisted tests compared to oven-heated thermal tension tests at similar temperatures, however, at a different heating rate supporting that the presence of an additional electrical–mechanical interaction during electrically-assisted deformation might be time sensitive. Observations of microstructure revealed the occurrence of local intergranular cavitation as well as a new phenomenon not yet associated with electrically-assisted deformation, local grain boundary melting, during high current density experiments. These results provide additional discussion materials for the enhanced plastic deformation associated with electrically-assisted deformation.