Abstract
Al-Mn alloys (3003) alloys are the preferred alloy series for brazed heat-exchangers for applications in the automotive industry. Cu, Si and other alloying elements are added in different amounts to improve alloy properties and achieve excellent thermal efficiency, high strength and corrosion resistance. Addition of Cu and Si results in longer solidification intervals which makes the alloys susceptible to hot-tearing and hard to cast. To investigate the influence of Cu and Si on the hot-tearing susceptibility, different amounts of these alloying elements were added to commercial alloys and a series of hot-tearing experiments were performed. Analysis of the experimental results were combined with theoretical analysis including hot-tearing indicators and microstructural simulations. An increase in the Cu and Si contents lead to increase in the hot-tearing tendency until a maximum was reached. A further increase decreased the hot-tearing tendency. The maximum is found at different concentrations for the alloys investigated and depend on the interplay between all alloying elements as well as the cooling rate.
