Influence of the microstructure on the corrosion behaviour of cast Mg-Al alloys

摘要

The influence of a-phase and beta-phase (Mg17Al12) on corrosion of cast binary Mg-Al alloys was investigated by immersion testing in 5 wt.-% NaCl solution saturated with Mg(OH)(2) and by measuring the corrosion potential E-corr. The microstructure of the alloys regarding Al-content of alpha-phase and amount of beta-phase was adjusted by solution heat treatments at various temperatures. Subsequently the continuity of beta-phase (C-beta) was measured. With increasing Al-content in the alpha-phase, the impact of C-beta decreases. The results show that the Al-content of the alpha-phase is a very important factor to influence the corrosion resistance.