The effect of homogenization temperature on the corrosion resistance of extruded 7050 Al-alloy bars

Abstract

The homogenization time is decreased from 28h to 6h by using high-temperature homogenization heat treatment. With increasing of the holding time, the content of intergranular phase decreases quickly at first. When the holding time is more than 6h, the content of intergranular phase keeps unchanged, and the area fraction of residual intergranular phase is 0.5%, lower than that (0.64%) of the two-step homogenization process. The mechanical properties of the extruded bars heat-treated by the high-temperature homogenization and the two-step homogenization heat treatment are almost the same. In the accelerated corrosion experiments, the maximum intergranular corrosion depth in the direction of perpendicular and parallel to the bar axis heat-treated by the high-temperature homogenization heat treatment are decreased by 43% and 60%, respectively, compared with that heat-treated by the two-step homogenization heat treatment.