Effect of Al-alloy composition and foaming temperature on pore size, density and mechanical properties

Sandwich aluminium foams were developed, with in-situ face sheets, by controlled powder forging and rolling. The parameters for forging, rolling and sintering were optimized for dif-ferent combinations of Aluminium (Al), Al-12Si alloy, Al-8Si alloy and flyash. The foaming of the precursor was recorded and the expansion with time was estimated using image analy-sis. The growth of the sandwich could lead to ~350-400% increase in thickness, before melt-ing of the face sheet, compared to the precursor without Al sheet that led to ~ 1000% expan-sion. The density varied between 0.35-0.90 g/cc and the average size of pores varied in the range of 2-5 mm. Compressive properties were evaluated and the total energy absorbed, up to 60% of deformation, was correlated with the density. The relation followed a power law with R2 value of 0.95.