Abstract: Abstract The 27% vol-SiC_w/6061A1 composite was fabricated by squeeze casting method.The aging dynamic process of the 27% ovol-SiC_w/6061A1 composite was studied at 170℃,and double aging peaks were found in the aging dynamic curves of the composite.The results of DSC analysis showed that the precipitation temperature of β' and β phase in the composite decreased by 56℃ and 76℃,respectively as compared with that in the 6061A1 alloy,from which the effects of the SiC whiskers on the precipitation processes of the composite were discussed.It is concluded that the double aging peaks resulted from the transformation of the precipitation from G.P.zones to β' phase,and this conclusion was further proved by TEM observation of the morphology of the precipitations in the 27% ovol-SiC_w/6061A1 composite.