Precipitated Al_2O_3 phase characterization in internally oxidized Cu-Al alloy sheets

摘要

Cu-Al_2O_3 composite sheets were prepared by Cu-Al alloy sheet internal oxidation. The Al_2O_3 precipitation phase was extracted from the Cu-Al_2O_3 composite sheets. The Cu-Al_2O_3 composite sheets were melted and then solidified to prepare Cu-Al_2O_3 bulk composite ingot. The crystal types and distribution of precipitated Al_2O_3 phase in the Cu-Al_2O_3 composite sheets and the ingot were investigated. In the Cu -Al_2O_3 composite sheet, the crystal types of the Al_2O_3 precipitation phase include γ-Al_2O_3, α-Al_2O_3 and θ-Al_2O_3. The main Y-Al_2O_3 phase has a coherent interface with the Cu matrix, and the amount of α-Al_2O_3 and θ-Al_2O_3 phases decreases from the surface to the bulk. During composite sheets melting, dispersed Al_2O_3 particles aggregated, and became isolated from the Cu matrix. Most of the γ-Al_2O_3 phase was transformed into the α-Al_2O_3 phase.