The metallographic etch for as-cast and solid solution treated samples of AZ91D magnesium alloy in sand casting and permanent mould casting has been performed

and as-cast microstructure and ESBD experiment of die casting AZ91D magnesium alloy have been investigated.The results show that the dendrites in as-cast microstructures of sand casting and permanent mold samples are characterized by sixtuple-symmetrical features

in which the angle between the primary dendrites is 60°

and the grain size can coarsen after solid solution.The absence of sixtuple-symmetrical features can be observed as a result of high cooling rate restraining the full growth of dendrites in die casting samples.EBSD experiment can accurately measure the grain size and grain orientation in die casting samples.