Abstract: The superplastic deformation behavior of SiCw/ZK60 composite was investigated at temperatures ranging from 573K to 723K and at initial strain rates ranging from 8.3× 10^-4s^-1 to 8.3×10^-2s^-1.A maximum elongation of 200 138325116th a m-value of 0.35 was obtained at 613K and a initial strain rate of 1.67×10^-2s^-1.The apparent activation energy(98kJ/mol)approximates that for grain boundary diffusion(92kJ/mol)in magnesium.It is proposed that the dominant mechanism of superplastic deformation in the present composite is grain boundary sliding accommodated by diffusional transport,besides,interfacial sliding plays an important role in the superplastic deformation.

Key words: magnesium matrix composite, superplasticity, apparent activation energy,