The influence of pouring temperature on the microstructure and fluidity of AE42 alloy

Purpose: The automotive use of magnesium is currently restricted to low-temperature structural components. Rare earth additions such as Ce, Nd, La and Pr are known to improve the creep performance. The aim of the research was to determine the effect of pouring temperature on the as-cast microstructure of AE42 magnesium alloy. Design/methodology/approach: The study was conducted on Mg-4Al-2RE (AE42) alloy after cast in different conditions. The microstructure was characterized by optical microscopy (Olympus GX-70) and a scanning electron microscopy (Hitachi S3400) equipped with an X-radiation detector EDS (VOYAGER of NORAN INSTRUMENTS). The phase composition of these alloys was identified by X-ray diffraction (JDX-75). A program for image analysis "MET-ILO" was used for determination of area fraction of intermetallic phases. Findings: The microstructure of AE42 alloy consists of α-Mg solid solution with divorced eutectic Mg17Al12 + α-Mg, Al11RE3 and Al8REMn4. Pouring temperature has an influence on the fluidity and microstructure. Research limitations/implications: The future research will contain creep tests and microstructural investigations of cast and die-cast alloys using TEM microscopy. Practical implications: Results of investigation may be useful for preparation of sand casting technology of the Mg-Al-RE alloys. Originality/value: This paper includes the results of microstructural investigations and effects of pouring temperature on the fluidity of AE42 magnesium alloy for gravity casting technology.