Aluminium cenosphere hybrid foam through stir casting technique

Abstract

newline Aluminium composite foams are potential materials for multifunctional applications because of newlinetheir excellent combination of physical and mechanical properties, higher surface area and ultralight weight. But their uses have been restricted to a few critical applications only because of newlinetheir high cost. Several attempts have been made to make aluminium foams in order to get newlineimproved properties at compatible costs. Even though a lot of efforts are made, the processing of newlinealuminium foams for precisely controlled porosities and densities are a difficult task. The newlinestrength, energy absorption its stiffness are strong function of aluminium foam architecture, newlinematrix alloys or composites and the processing route. This is because of the fact that strength of newlinefoams and its deformation mechanism varies with the processing conditions, and all or composite newlinestructure. The distribution of pore in conventional aluminium foams are quite inhomogeneous newlinewhether these are made through powder metallurgy or liquid metallurgy route. For making newlinealuminium foam two things are used: (i) foaming agent and (ii) thickening or stabilizing agent. newlineGenerally ceramic particles are used as thickening agent. By varying the thickening agent the newlineviscosity of the melt is controlled. Temperature is another factor to control the viscosity of the newlinemelt. Metal hydrides are used as foaming agent. Depending on requirement of density and cell newlinesize, the temperature, foaming agent and melt temperature are controlled. Most of the literature newlinesuggests use of 1 to 1.5 wt% foaming agent for foaming and this cause the high cost of newlinealuminium foam. Thus there is a need to make some solution to make foam using lower quantity newlineof foaming agent and also to improve its mechanical strength and energy absorption. In this newlinedirection it is thought to make a feed stock which contains around 30 to 40% porosity by using newlinecenosphere microball