Powder cladding diffusionalloying on the surface before and after nanocrystallined treatment of Mg-Gd series wrought magnesium alloy was carried out by vacuum high-temperature microwave oven. Microstructure features and structure refinement at different deformed zones on surface along thickness direction were observed by OM （optical microscope） and TEM （transmission electron microscope）

and phase constituent in the alloyed layer at different microwave treatment conditions was analyzed by XRD （X-ray diffraction）. The results show that microstructure and its structure in the deformed zone exhibit gradient distribution

and nano-crystalline with clear boundary and 10

2

0 nm in diameters can be observed on surface of the Mg-Gd alloy specimens. Aluminized behavior on the nanocrystallined surface of Mg-Gd alloy is realized at 320 ℃ as a result of microwave induction greatly decreasing diffusion-alloying temperature. In addition

diffusion-alloy process is promoted due to high volumetric fraction grain boundary and severe distortion. At the same experimental conditions

thickness of alloyed layer on surface nanocrystallined Mg-Gd alloy is 2

3

times thicker than that without nanocrystallined ones.