Abstract
The electrical-assisted tensile tests of 5086 Al alloy sheets with different current parameters were carried out at room temperature with a frequency of 150 Hz and voltages of 50 V, 60 V and 70 V. It was found that the serrated plastic instability (named PLC effect) was eliminated as the pulse current increased to 150 Hz/60 V, but the PLC effect was observed with 150 Hz/50 V. To distinguish the thermal effect and athermal effects of pulse current on PLC effect, the comparative heating tensile (HT) test in furnace with a temperature rising trend of 150 Hz/60 V was conducted. The obtained curves still showed serrated flow behavior, indicating that the thermal effect was insufficient to suppress the PLC effect. The influence of pulse current on the microstructure and texture evolution was investigated through TEM and EBSD. According to the microscopic analysis, the pulse current accelerated the solute atoms' diffusion and dislocation movement. S orientation {123}<634> of 150 Hz/60 V presented more obvious transformation compared with that of HT specimen. It was illustrated that the athermal effect of pulse current plays an important role in the crystal orientation and suppressing the PLC effect.
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