Characteristics of microstructure and banded defects in die cast AM50 magnesium components

A number of commercial AM50 magnesium alloy components have been die cast under various casting conditions. The influence of process parameters on the microstructural features as well as on the defect known as the 'segregation band defect' were investigated. It was found that pouring temperature and injection speed have obvious effects on the morphology of presolidified crystals inside the casting. More presolidified crystals were formed under the condition of lower pouring temperature, and more broken dendrites and spherical crystals were formed under higher injection speed. A variety of segregation band morphologies and the influence of various casting conditions on the appearance of band type defects were examined. It was discovered that intensification pressure has the strongest influence on the appearance of segregation bands inside the castings. By applying high intensification pressure, the risk of tearing along the bands and the segregation levels inside the band were both dramatically decreased. The influence of band defects on the mechanical properties of the components was established.