The fast diffusion paths of copper atoms in Al–Cu–Si alloys

Copper diffusivities were measured in both α single phase and α plus silicon phase Al–Cu–Si alloys by diffusion couple experiments. The results exhibits that copper atoms has much faster diffusion rate in the α plus silicon phase Al–Cu–Si alloy than in the α single phase Al–Cu–Si alloy, which means silicon phase plays an important role in copper diffusion in the alloy. Copper has very high diffusivity in the silicon phase, silicon particles become shortcuts for copper diffusion in the alloy. How much the silicon phase can increase copper diffusivity depends on silicon's volume percentage and morphology.