Two kinds of copper matrix composites reinforced respectively with nano-SiO_2 and nano-AlN were prepared by powder metallurgy technique. The microstructure and
Superplasticity of AZ31 Mg alloy at the temperature range of 250-450℃and stain rate range of 0.7×10-3-1.4×10-1 s-1 was examined through uniaxial tensile test