Foaming of Al-1.5 percent Ca alloy melt was studied as a function of foaming agent powder particle size and foaming agent powder surface filming. The response variables were height of foam and that of dense bottom portion, expansion rate and cell structure. Over the range of foaming agent powder particle size studied (from < 8 mu m to 75-106 mu m), the finest and most uniform cells were obtained when < 8 mu m powder was used. Surface filming of the foaming agent powder was shown to result in slower expansion, but treatment-dependent cell structure. Studies were also conducted to explore the viability of foaming commercial purity (CP) Al, Al-3 percent Mg and Al-2 percent Mg-l percent Li. While all the alloys could be foamed, Al-1.5 percent Ca foams showed the most well defined cell structure and the largest expansion.
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