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 AlMg5Si2Mn alloy. Results indicated that the microstructure of the die-cast AlMg5Si2Mn consists of alpha(1)-Al grains, fine-size alpha(2)-Al grains and (Al + Mg2Si) eutectic. The surface layer observed has the thickness in a range of 120-135 mu m, while an ellipse-like surface layer edge is observed in the corner of the plate-like sample. Tensile strength and elongation (delta) of the specimens are slightly decreased along the die-filling direction due to the backflow of melt. Pure (Al + Mg2Si) eutectic layer and ultra-fine-size alpha(2)-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.