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Lecture

Experimental investigation of the electro plastic effect in polycrystalline pure Mg and WE 43 alloy

Thursday (27.09.2018)
10:30 - 10:45 S1/03 - 283
Part of:


The electro plastic effect (EPE) occurs in materials exposed to high electric currents, in the order of 10E2 to 10E4 A mm^-2. Current pulses with duration of about 10E-3 s are usually used to limit resistive heating of the sample. As a result, a reduction of flow stress and enhanced ductility is observed. The EPE may therefore be exploited to support the deformation of inherently brittle material. The underlying microscopic mechanisms enabling the flow stress reduction and increase in ductility are still unresolved.

In the present study, the EPE was investigated using samples of extruded pure magnesium and WE 43 Mg alloy, which were subjected to current pulses with a current density of 700 A mm^-2 during compression in the elastic regime. In the first step, the experimental conditions while pulsing particularly with respect to the electrical contact of the samples in the compression machine was optimized. During the experiments, a significant drop of stress and the occurrence of residual plastic strain was observed. Subsequent microstructural observations using EBSD mapping showed the appearance of intense twinning and dislocation flow. The twin types were characterized and their distribution was quantified using misorientation profiles. Dislocations were quantified using kernel average misorientation distributions.

 

Speaker:
Dr. Abhishek Tripathi
Max-Planck-Institut für Eisenforschung GmbH
Additional Authors:
  • Andrej Dalinger
    Leibniz Universität Hannover
  • Dr. Gregory Gerstein
    Leibniz Universität Hannover
  • Dr. Abhishek Tripathi
    Max-Planck-Institut für Eisenforschung GmbH
  • Dr. Stefan Zaefferer
    Max-Planck-Institut für Eisenforschung GmbH
  • Franz Körkemeyer
    Leibniz Universität Hannover