Microstructure and mechanical properties of Mg-5Gd-3Nd-0.5Zr alloys containing different Y contents were investigated under different conditions. The results reveal that compounds at grain boundary in the alloys are mainly composed of Mg24Y5

Mg41Nd5 and Mg5Gd

furthermore

with increasing in Y content

the numbers and grain size of the compounds at the grain boundary are increased

however

average grain size still keeps approximately 50

6

0 μm

showing slightly change. After homogenization treatment at 535℃ for 24 hours

compounds in the alloys are converted from continuous island structure at as-cast state into dispersively fine particles

where dispersively distributed particles in the alloys are mainly composed of Mg24Y5 and Mg41Nd5 phase while Mg5Gd phase is mostly decomposed and dissolved into the matrix. After extrusion

the microstructure with approximately 20 μm in average grain size can be observed in the alloy

and tensile strength

yield strength and elongation of the alloys can be greatly improved

in which desirable comprehensive mechanical properties can be observed in Mg-5Gd-5Y-3Nd-0.5Zr. The Y content should be controlled less than 5% in weight in designed alloys.