Magnesium alloy with 5 wt% Al, 0.35 wt% Mn and 5 wt% rare earth elements (RE) was prepared and gravity cast into a sand mould. Microstructure investigations were conducted. Analyses of the Mg-Al-RE alloy microstructure were carried out by light microscopy, scanning electron microscopy and the XRD technique. In the as-cast condition, the alloy was composed of α-Mg, Al11RE3 and Al10RE2Mn7 intermetallic phases. Additionally, due to non-equilibrium solidification conditions, an Al2RE intermetallic phase was revealed.
US A356 and US 413 cast aluminium alloys shrinkage characteristic have been discussed in the present study. Specific volume reduction leads to shrinkage in castings and it can be envisaged as a casting defect. Finite difference based casting process simulation software has been used to study the shrinkage characteristic and it is quantified using mathematical formulae. The three dimensional model of the shrinkage defect has been constructed using CAD application software. Shrinkage characteristic has also been quantified through experimental validation studies and compared well with casting process simulation. Shrinkage characteristic study and control is essential for producing defect free castings. Influence of casting shape on the shrinkage characteristic has been studied in this paper.