Papers by Author: Kevin Gatenby

Abstract: The heat exchanger market requires aluminum brazing sheet that offers a good balance of properties, namely: corrosion resistance, brazability, and post braze strength. A new long life brazing sheet alloy which has attractive properties in the post braze condition has been developed. Specifically, higher post braze strength and improved air side corrosion resistance has been obtained. In addition, a deeper understanding of dense precipitate band (DPB) formation in higher Si containing core alloys during brazing has been developed. The new alloy will lead to improvements in radiator tube stock performance.

Abstract: The influence of different cooling regimes on the surface microstructure of strip cast AA1XXX alloys was investigated. The cooling rate was varied over a wide range using a bench scale simulation apparatus. It was found that the type and morphology of the intermetallics varied over a wide range both at the cast surface and in the near surface regions. These observations were compared to the compounds formed in the bulk of the slab. It was found that, a surface layer containing a high concentration of alloying elements, an inverse segregation layer, forms under some conditions and can result in a high density of intermetallics. By varying casting conditions, the mechanism of formation for these structures was studied. The surface microstructure of the slabs was characterized as a function of the different local cooling regimes.