A COMPARATIVE STUDY OF THE MICROSTRUCTURES OF CONTINUOUS CAST-ROLLED AND CONVENTIONAL WROUGHT ALUMINUM ALLOY PRODUCTS

摘要

The differences in the microstructures of wrought aluminum alloy products produced via the continuous-casting-rolling and the conventional ingot-casting-rolling routes have been investigated. Irrespective of alloy composition, the microstructures of the products produced via the continuous casting route consist of bands of eutectic colonies elongated and strung out in the rolling direction surrounded by regions depleted in second phases. In contrast, the microstructures of conventional wrought products consist of a uniform distribution of comparatively coarser constituent phase particles. Most importantly, wrought aluminum alloy products produced via the continuous casting-rolling route do not contain the matrixstrengthening dispersoids. The differences in microstructure are attributed to the different prevailing solidification conditions in ingot and continuous casting processes. They appear to explain the differences in the response of the two types of wrought products to post-casting processes and their attendant properties and performance.