Al2O3 Crystal Type and Distribution of Internal Oxidized Cu-Al Alloy Sheet

Cu-Al2O3 composite sheets were prepared by the internal oxidation of Cu-0.50 wt%Al alloy sheets at 900 degrees C for 25 h. An enrichment extraction method was used to extract Al2O3 phase in Cu-Al2O3 composites. The type, distribution, relationship with the Cu substrate interface of Al2O3 phase in the Cu-Al2O3 sheets were studied by TEM. The extracted powder was studied by X-ray diffraction (XRD) and TEM. The results show that the precipitated phases of Cu-Al2O3 composites by the internal oxidation of Cu-Al alloy sheets are mainly gamma-Al2O3, as well as a few alpha-Al2O3 and theta-Al2O3. The Al2O3 particles are distributed in the Cu matrix and completely coherent with the Cu matrix. From the surface to the depth of 0.5 mm, the size of Al2O3 particles is reduced from 14 nm to 5 nm while the spacing of Al2O3 particles is increased from 10 nm to 15 nm.