The Mg-Al/Al gradient composites with the magnesium in internal layer and pure aluminum in external layer have been prepared by double-streaming-pouring techniques. The results show that the metallurgical bonding can be generated between magnesium alloy and pure aluminum

and the gradient distributed transition zone of the components and hardness can be observed in the composites. In addition

the prepared composites possess a desirable responding relationship among the composition

macro-structure and hardness. However

the sharp density difference between the Mg alloy and pure aluminum can cause the dramatic mixture of the two melts to result in the sharp composition variation of the internal alloy.