Search Results

The microstructure and silicon particle morphology of Al-Si cladding alloys are known to influence brazing properties and the quality of brazed joints. This paper reviews published literature on Al-Si system, melting mechanisms, grain size, solid state silicon particle growth and the influence on brazed joint formation. Common filler metals used for brazing sheet were thermally treated to modify Si morphology. The resultant microstructures were examined and Differential Scanning Calorimetry used to establish thermodynamic properties. The impact of silicon concentration and particle morphology on the melting kinetics is discussed.

The application of aluminium alloy materials for automotive heat exchangers, including engine cooling and air conditioning systems, is now widespread. To meet the industry demands of both extended service life and improved reliability for heat exchanger components, it is important that the critical factors influencing corrosion behaviour are properly understood, particularly with the trend towards downgauging of materials. To maximise resistance to waterside corrosion, manufacturers have adopted the approach of using an internal cladding, commonly a high purity or zinc - containing alloy, to provide sacrificial protection of the core material. Recent studies have shown that the presence of an internal cladding can, under certain conditions, promote rapid localised attack of the core alloy.