High corrosion resistance and strain hardening of high Mg Al-alloy with Er and Zr by using a new reverse stabilization process

An abnormal reverse transition of intergranular corrosion from sensitization to stabilization was observed in the Al-6.4 Mg-0.43Mn-0.37Er-0.17Zr alloy at low annealing temperatures between 220 and 260 degrees C for the first time. The reverse stabilized alloy annealed at 240 degrees C for 5 h had excellent long-term corrosion resistance in the deformed state. The corresponding transmission electron microscopy analysis showed that Al3Mg2 precipitates distributed separately along grain boundary, at triple junctions and the Al6Mn phase boundary. The combination of the low temperature reverse stabilization and retarded recrystallization by addition of Er and Zr caused the high Mg aluminum alloy to exhibit high corrosion resistance and strain hardening. (C) 2019 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.