Microstructure,Mechanical Properties and Die-Filling Behavior of High-Performance Die-Cast Al-Mg-Si-Mn Alloy

This work aims to reveal the relationships between the microstructure,mechanical properties and flow behavior of die-casting AlMg;Si;Mn alloy.Results indicated that the microstructure of the die-cast AlMg;Si;Mn consists of α;-Al grains,fine-size α;l grains and（Al +Mg;Si） eutectic.The surface layer observed has the thickness in a range of120-135 μm,while an ellipse-like surface layer edge is observed in the corner of the plate-like sample.Tensile strength and elongation（5） of the specimens are slightly decreased along the die-filling direction due to the backflow of melt.Pure（Al + Mg;Si） eutectic layer and ultra-fine-size α;-Al grains observed are around the overflow channels.Mass feeding is predominantly responsible for the superior mechanical properties of the round bars as compared to those of plate-like samples.