Existing morphology and precipitate characteristics of RE Er in as-cast

as-homogenized and cold rolled Al-4.7Mg-0.7Mn-0.1Zr-0.3Er alloy were observed by SEM（scanning electron microscope）

TEM（transmission electron microscope）.The results show that in non-equilibrium solidification condition

minor Er existed in theα-Al solid solution

while major Er is continuously or die-continuously distributed on the grain boundary in form of primary Al3Er phase.Although Er is likely to segregate with Mn and Fe

it is difficult to generate Er-Mn intermetallic compound.Solid solution Er can be precipitated from the alloy in form of sub-Al3Er phase during homogenization annealing process.In addition

continuous or dis-continuous Al3Er phase distributed on the grain boundary would not be decomposed and resolved in subsequently heat treatment

and they are broken during hot rolled or cold rolled process.The dispersely distributed Al3Er phase in the cold rolled plate exhibits desirable coherent/semi-coherent with the matrix

which could be acted as effective strengthening phase in the alloy.