Influences of alloying elements, solution treatment time and quenching media on quality indices of 413-type Al-Si casting alloys

Quality charts were generated using four models of quality indices in order to evaluate the mechanical properties and quality of T4-treated 413-type Al-Si casting alloys. The purpose of this study is to investigate the influence of a number of parameters on the mechanical properties and quality of 413-type alloys. These parameters are the addition of the alloying elements Sr, Mg, Cu, Ag, Zn, La, Ce and Ni; the solution heat-treating time for periods of 4 and 24h; and two quenching media: ambient air and hot water. Analysis of the quality maps generated shows that the alloying elements have a considerable influence on mechanical properties but only a slight influence on alloy quality. It was observed that solution heat-treating for a period of 24 h does not have any significant effect on material strength although some positive influences may be observed on ductility and quality of the alloys under investigation as compared to the 4 h-duration. Using hot water (60 degrees C) as a quenching medium improves both the strength and the quality of these alloys. Quality indices and quality charts are useful tools for engineering applications with a view to facilitating the selection of the most suitable processing conditions and to obtain the best compromise between quality and mechanical properties of the alloys investigated. Making use of quality charts will contribute to the selection of the most appropriate alloys for a particular application in accordance with service conditions in real life. (C) 2008 Elsevier B.V. All rights reserved.