Modelling Temperature Profiles and Flow Velocities During Melt Filtration in Permanent Mould Casting of AZ91E Magnesium Alloy

The objective of this research was to examine melt filtration of AZ91E magnesium alloy permanent mould castings using experimental trials and predict filtration using a commercial software package. Tensile specimens were prepared using a H13 tool steel permanent mould machined to ASTM-B108 standards. The mould and pouring temperatures were 500 and 720?°C, respectively. Without a filter, the average yield strength, tensile strength and elongation were 89.6, 153.9?MPa and 2.41?% respectively and these increased to 96.5, 167.0?MPa and 3.05?% respectively with the use of a steel mesh filter within the well of the mould. Filters enabled removal of MgO based oxides. Modelling using commercial software demonstrated that the use of filters reduced turbulence in the metal stream minimizing oxides, which are essentially sites for stress concentration. The results of the research are important for the development of processing methods to improve the melt cleanliness of magnesium alloys for automotive and aerospace industries.