Effect of Silicon Content on Mechanical Properties and Progressive Collapse Behavior of Closed-cell Aluminum Foams

Aluminum foams with different silicon content have been produced by the Alporas method, where calcium and calcium carbonate are used as a thickening and foam agent, respectively. Performing quasi-static compression tests, mechanical behavior such as strain-stress diagram, deformation behavior, and energy absorption properties of the produced foams were investigated in this study. By adding silicon, calcium, and agitation of molten metal Si, SiO2, CaAl2Si2, CaAl2Si2O8 phases were created. These phases increased melt viscosity and improved foamability. The effect of physical properties, foam structure, alloy microstructure, pore size, and distribution on the mechanical behavior of metal foams was investigated in the present study. The foam with 8 wt% Si showed minimum density and maximum foamability, while it possessed a complete peak of stress. Thinner cell walls in Al-Si foams were observed, which could be attributed to the effect of silicon on melt's surface tension. Results suggested that foams with 0 and 8 wt% Si are suitable for use as an energy absorber.