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Abstract

Composite metal foams (CMFs) are a new class of closed-cell porous materials that can be produced by distributing metallic spheres in a metallic matrix using casting or powder metallurgy techniques. CMFs could offer better mechanical performance in comparison to the conventional porous materials due to the uniform shape and even distribution of voids. To evaluate elastic properties of CMFs, the conventional theoretical approaches for periodic models are not good candidates due to the random distribution of voids in these materials. Thus, in this research, first, a three-dimensional CMF model is developed based on the Lubachevsky and Stillinger (LS) approach, which is then used for the finite element analysis. With the aid of finite element simulation and homogenization technique, the elastic properties of the CMFs are evaluated focusing here on elastic modulus and Poisson's ratio. It is assumed that the CMFs are produced through powder metallurgy technique, where steel spheres are distributed randomly in either aluminum or steel matrix, called AL-S and S-S CMFs, respectively. Comparing results against experimental results shows a very good agreement. In this paper, for the first time, effects of geometrical and material parameters such as thickness of the spheres, microporosity in the wall of spheres and matrix, matrix materials, and diameter of the spheres on the elastic properties of CMFs are examined. It is observed that the microporosity in the matrix has higher effect on the elastic modulus of the CMFs than the microporosity in the wall of the spherical particles.