Presentation of patented secondary magnesium alloy – Subsequent basic research: Investigation of influence of dendritic microstructure on corrosion properties.

As first step in the past a patented secondary magnesium alloy AZC1231 (Aluminium = 12mass.-%, Zinc = 3mass.-% and Cu = up to 1 mass.-%) was developed to close the loop of magnesium material flow. The impurity tolerant AZC1231 was tested in a real die casting process to prove feasibility resulting in navigation device housing. Corrosion properties show interesting effects because the noble copper was disposed by copper solving and copper encircling phases. The influence of the microstructure plays therefor a very important role. A new basic research project was started to investigate dendritic microstructure regarding grain size, dendrite formation, eutectic refinement and distribution of Mg17Al12(β)-phase of magnesium alloys with aluminium contents from 0 to 12 mass.-%. The aim is evaluation of secondary dendrite arm spacings at defined cooling conditions which are responsible for a columnar or equiaxed macrostructure containing dendritic microstructure. Subsequent corresponding corrosion behaviour has to be examined by immersion testing method.