The effects of applying an electromagnetic interaction of low intensity (EMILI) on the microstructure and corrosion resistance of 7075-T651 Al alloy plates (13 mm in thickness) during modified indirect electric arc (M...The effects of applying an electromagnetic interaction of low intensity (EMILI) on the microstructure and corrosion resistance of 7075-T651 Al alloy plates (13 mm in thickness) during modified indirect electric arc (MIEA) welding were investigated. The welding process was conducted in a single pass with a heat input of ~1.5 kJ/mm. The microstructural observations of the welds were correlated with the effect of EMILI on the local mechanical properties and the corrosion resistance in natural seawater by means of microhardness measurements and electrochemical impedance spectroscopy, respectively. Microstructural characterization of the welds revealed a grain refinement in the weld metal due to the electromagnetic stirring induced by EMILI of 3 mT during welding. In addition, observations in the scanning electron microscope showed that the precipitation of Cu-rich phases and segregation of eutectics were reduced in the heat affected zone (HAZ) also as an effect of EMILI. The high corrosion dissolution of the 7075-T651 welds in natural seawater and the extent of overaging in the HAZ were reduced when welding with EMILI of 3 mT. Thus, EMILI along with the MIEA technique may lead to welded joints with better microstructural characteristics, improved mechanical properties in the HAZ and reduced electrochemical activity.展开更多
文摘The effects of applying an electromagnetic interaction of low intensity (EMILI) on the microstructure and corrosion resistance of 7075-T651 Al alloy plates (13 mm in thickness) during modified indirect electric arc (MIEA) welding were investigated. The welding process was conducted in a single pass with a heat input of ~1.5 kJ/mm. The microstructural observations of the welds were correlated with the effect of EMILI on the local mechanical properties and the corrosion resistance in natural seawater by means of microhardness measurements and electrochemical impedance spectroscopy, respectively. Microstructural characterization of the welds revealed a grain refinement in the weld metal due to the electromagnetic stirring induced by EMILI of 3 mT during welding. In addition, observations in the scanning electron microscope showed that the precipitation of Cu-rich phases and segregation of eutectics were reduced in the heat affected zone (HAZ) also as an effect of EMILI. The high corrosion dissolution of the 7075-T651 welds in natural seawater and the extent of overaging in the HAZ were reduced when welding with EMILI of 3 mT. Thus, EMILI along with the MIEA technique may lead to welded joints with better microstructural characteristics, improved mechanical properties in the HAZ and reduced electrochemical activity.
