Effect of extrusion welding locations on the corrosion of AM30 alloy extrudate

Abstract

The effect of extrusion welding at three different locations on the corrosion of a magnesium alloy (AM30) extrudate after being immersed in 3.5% NaCl solutions for 1 h, 12 h, and 24 h has been investigated. Different electrochemical methods namely, cyclic polarization, open-circuit potential, electrochemical impedance spectroscopy, and current–time measurements were employed. The corroded surfaces were characterized using various spectroscopic analyses. All electrochemical measurements confirmed that the corrosion of the Mg alloy extrudate changes depending on the location of the extrusion welding, which affects the values of the obtained corrosion current, corrosion rate, and corrosion resistance. The severity of corrosion was found to decrease with prolonging the exposure periods of time in the chloride solutions for all taken samples at the different locations of the extrusion welding. This was further confirmed by the scanning electron microscopy micrographs and the energy dispersive X-ray profiles taken for the corroded surfaces of the different extruded AM30 samples. Keywords: Corrosion, Magnesium alloys, Extrusion welding, Cyclic polarization, EIS, Chronoamperometry