As-cast microstructure feature of Al sheet used for pressure can manufacture with high forming properties prepared by different melt-treatment technology was investigated and analyzed with the aids of SEM

EDAX

TEM and selected area electron diffraction（SAED）

etc. It is found that oxide inclusions in the Al sheet are mainly γ-Al2O3

and Fe-rich impurity phases in the sheet are mainly Al3Fe

T1 （Al12Fe3Si） or （AlFeSiRE）

and the crystal structure of （AlFeSiRE） phase is too complicated to determinate it. The effect of melt-treatment technology on the as-cast microstructure of the sheet is remarkable. When the Al sheet is prepared by no or conventional melt-treatment

there are a number of oxide inclusions

these inclusions distribute non-uniformly and gather together in the larger block form

and their size is about 10-40 μm. Fe-rich impurity phases in the sheet are mainly Al3Fe and T1

and a few of the meta-stable phase Al6Fe exist in Al sheet. These Fe-rich impurity phases appear in the coarse

long needle/flake or skeletal form

and are easy to gather together with oxide inclusions. When the Al sheet is prepared by high-efficient melt-treatment

the number of oxide inclusions is very few obviously

and their size is about or less than 4μm

and their distribution is uniform; Fe-rich impurity phases are mainly （AlFeSiRE）

and a small amount of Al3Fe phases also exist in the material. （AlFeSiRE） phases distribute uniformly along grain boundary in tiny group/sphere or short stick form. The phenomenon that Fe-rich phases gather together with oxide inclusions is not discovered in the material.