The 7075/6009 gradient aluminum alloy composites have been prepared by double-stream-pouring semi-continuous casting.The macro-structure and micro-structure and composition distribution in the internal
transitional and external layers of the ingot have been analyzed
and the Rockwell hardness in radial of the ingot has been measured also.The results indicate that the 7075/6009 aluminum alloy composites with gradient distribution in composition and hardness can be successfully prepared by optimizing processing parameters.The turbulent flows is dominant in internal and external alloy melt solidification process.The width of the transitional region is dependent on the pouring temperature of internal and external alloy melt
aperture of the throttle bore and the depth of the nozzle submerged in the mold.