The mechanical properties and microstructure of Al-4.5Mg-0.7Mn-0.4Er alloy prepared with iron mold

water cooling mold and semi-continuous casting have been described by tensile testing

optical microscope

SEM （scanning electronic microscope）

XRD（X-ray diffraction） and TEM （transmission electron microscope）. It is found that increasing cooling rate can improve the strength of Al-4.5Mg-0.7Mn-0.4Er alloy

and be helpful for the formation of supersaturation solid solubility of Er and Mn element in Al during solidification process and for the precipitation of fine and dispersive Al3Er phase and Al6Mn phase after homogenized annealing treatment. Fine and dispersive Al3Er phase can be acted as the effectively strengthening phase in the Al alloy

which is helpful for improving the mechanical properties and microstructure of the alloy.