STAGE 3 : OPTIMIZATION OF THE COMPOSITIONS (I.E., THE RATIO OF THE ALUMINUM ALLOY TO THE CERAMIC PARTICLES), THE POROUS STRUCTURE, THE MECHANICAL PROPERTIES AND THE ENERGY ABSORPTION CAPABILITIES OF THE ALUMINUM/CERAMIC COMPOSITE FOAMS.

The CI’s previous research results indicated that the porous structure of the Foamed material is influenced by the composition and the manufacturing process. Furthermore, the mechanical properties and the energy absorption capability are largely determined by the relative density of the porous material and also, depending on the composition and the microstructure of the cell edge material.

Therefore, the compositions, i.e. the weight ratio of the Aluminum alloy, the Ceramic particles and the Foaming agent (titanium hydride) and the microstructures derived from different processing parameters will be investigated. The effects of the constituents of Aluminum alloy and Ceramic on the mechanical property and the energy absorption capability will be evaluated. Optimization of the compositions and the microstructures will be performed at this stage.

The plateau stresses and the Young’s moduli of Foamed materials are modeled by Gibson and Ashby as shown in equations (1) and (2). The energy absorption of Foamed materials can be evaluated by integrating the areas under the compressive stress – strain curves. Thus, the energy absorption capability of the Foamed materials is affected by the plateau stress also. The CI’s previous researches showed that the exponents n1 and n2 in equations (1) and (2) are depending on the deformation mode.

For a cellular material, the cell edges can be deformed in different deformation modes such as brittle fracture, bending, yielding and bulking under compressive loading. Therefore, the microstructure and the composition of the Aluminum/Ceramic Foam will be tailored to ensure that the Foam deforms via a deformation mode that shows a high plateau stress.