REVIEW OF HOT TEARING STUDIES IN Al ALLOYS DURING DIRECT CHILL CASTING

摘要

DC casting is a well established casting method for producing aluminum and magnesium alloys. One of the major defects frequently encountered in DC casting ingots is hot tearing which originates during the phase transition region. Previous research works reported that the copper content significantly lengthen the solidification interval and further certain critical concentration makes the alloy highly prone to hot cracks (so-called delta curve). In this work, the existing thermal, mechanical, and thermo mechanical hot tearing criteria are extensively reviewed. The critical solid fraction (0.9-0.99) is more focused where the ductility of the material changes drastically. The strength of the solid skeleton, dendritic network, feeding possibility, viscosity of the liquid, alloying element segregation, and cooling profiles are the important parameters considered for the integration of all the existing criteria.