Eutectic solidification in Mg-9Al-0.7Zn: From divorced to coupled growth

In hypoeutectic Mg-Al-based alloys, Mg17Al12 forms in the last stages of solidification by a eutectic reaction that is usually fully or partially divorced. Here we investigate nucleation, growth and morphology Mg17Al12-containing multicomponent Mg-9Al-0.7Zn-0.2Mn alloy. Under all conditions studied, formed an interconnected skeleton 3D orientation domains spanned multiple α-Mg grains, indicating nucleation events are relatively infrequent. While most regions α-Mg+Mg17Al12 had no preferred relationship (OR), occasional Burgers OR may be related to on during solidification. It shown degree divorced depends simple geometrical measure for space available involving dendrite arm spacing, fraction spacing. We then demonstrate coupled microstructures can generated this alloy independently manipulating magnesium time cooling rate.