Influence of Different Processes on Corrosion Performance of Al 1070 Alloy in Chloride Media

Abstract

Al 1070 alloy pins were subjected to four passes of micro/meso-scale equal channel angular pressing at room temperature in the current work. The channel diameter of 1.5 mm is the smallest channel diameter ever obtained in meso-scale processing. The effect of Al 1070 alloy processes on corrosion behavior in 3.5%NaCl and different concentrations of HCl solutions was investigated. The investigated alloy was processed by ECAP by four passes and different speeds of extrusion. Corrosion assessments were carried out by chemical technique (weight-loss method) in 3.5%NaCl, 0.2M HCl, and 1M HCl for two different times of 1h and 4h. The highest corrosion resistance is for one pass ECAP in HCl solutions. Among the different extrusion speeds, the samples with an extrusion speed of 1 mm/min demonstrated the lowest corrosion rate across all tested environments. The average grain sizes of 28.77 and 22.67 μm correspond to the extrusion speeds of 1 and 15 mm/min, respectively. As the extrusion speed increases, the grain size decreases. The surface morphology of the corroded Al 1070 alloy was further examined using scanning electron microscopy (SEM). Pitting corrosion was observed in all surface morphologies, highlighting the susceptibility of the alloy to this form of corrosion under the investigated conditions.