Melt Treatment Optimization of 5XXX and 6XXX Alloys for Ablation Technology

Ablation technology is an emerging casting technology which presents several advantages associated to the high cooling rate that strongly modify solidification microstructure. One of its most interesting capabilities is that it allows to manufacture un-castable alloys by any other conventional casting processes such as alloys of 5XXX and 6XXX series.
The present work optimizes the melt treatments: grain size refinement, degassing and deoxidizing treatments for these two types of alloys. The effect of two different grain refiners was compared to unrefined melt for the two types of alloys. The refinement potential was assessed by thermal analysis and microstructural evaluation. Density index, microinclusion and macroinclusion tests allowed to evaluate the hydrogen content and metal cleanliness for each melt treatment. As main result, the optimized melt treatment is defined for these 5XXX and 6XXX alloys suitable to be manufactured by ablation technology.