ISSUE 4/2012

/// 04
Pabel, T.; Bozorgi, S.; Kneißl, C.; Faerber, K.; Schumacher, P.
Effect of alloying elements on hot cracking susceptibility of AlSi7MgCu-alloys

Hot cracking during solidification can be a serious problem in aluminium casting alloys under certain conditions. This feature is well known but still insufficiently investigated in shape casting. This study gives a brief overview of the factors influencing hot cracking during shape casting. Five different AlSi7MgCu-alloys with varying Mg and Cu contents were examined. Theoretical models including the cracking susceptibility coefficient (CSC) from Clyne and Davies have been considered. Thermodynamic calculations of the behaviour of the fraction solid during solidification have been compared to an experiment based hot cracking indexing (HCI) method. Scanning electron microscopy (SEM) was used to compare existing microstructure and precipitated thermodynamic phases. Furthermore, SEM was used to investigate crack surfaces initiated by a dog bone shaped mold during casting. A good correlation between theoretical models and the experimental hot cracking index method was observed.

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