Influence Of Alloying, Pore Structure And Filler On The Compressive Behavior Of The Open-Cell Aluminum Foams

The mechanical behavior of aluminum foams is determined by mechanical properties of the matrix material, pore structure and relative density. So, it is very important to study the variation of the mechanical behavior and properties of the aluminum foams with the factors above for the purpose of optimizing the pore structure, further increasing the mechanical properties and energy absorbing capacity of the materials. The main purpose of this paper is to investigate the influence of alloying of matrix, pore structure and fillers on the compressive behavior and energy absorbing capacity of aluminum foams with quasi-static and dynamic compressive experiments.The open cell foamed commercial pure Al, AlSi12, AlSil2Mg0.4 and AlSi8Cul.6Mg0.4 alloy were prepared by the infiltrating process respectively. The influence of alloying elements such as Si, Mg and Cu on the compressive properties and energy absorbing capacity of the aluminum foams was studied by the quasi-static compressive experiments. The experimental results indicate that the yield strength, elastic modulus and flow stress of the aluminum foams are increased greatly through multiply alloying of the matrix. However, the plasticity of the aluminum foams is decreased by multiply alloying, and the strain-stress behavior of the multiply alloyed aluminum foam is characterized by the feature of a brittle foam in the compression. Without densification, the multiply alloyed aluminum foam exhibits a prolonged plateau region in its strain-stress response to the compression. In addition, the yield strength and flow stress of the aluminum foam are increased by addition of the alloying elements such as Si, Mg and Cu, more excellent absorbing capacity are obtained in the aluminum alloy foams, as a result.A kind of AlSi12 foams with silicate rubber filler was fabricated through infiltrating the liquid silicate rubber into the open-cell aluminum foam. And the quasi-static as well as dynamic compressive experiments have been conducted to investigate the influence of the silicate rubber on the mechanical behavior of the AlSi12 foam. Due to the incompressibility of the filled silicate rubber, the deforming mechanisms of micro-structure and stress-strain response of the aluminum foam are altered. Unlike the AlSi 12 foam without filler exhibiting three regions in compression, the AlSi 12 foam filled with silicate rubber behaves like a dense matter in the static compression. However, the AlSi 12 foam with silicaterubber filler exhibits the stress-strain response of a foamed material during dynamic compression, for a linear elastic region and a plateau region are observed in its strain-stress curve. Furthermore, the AlSi12 foam with silicate rubber filler has a more distinct strain rate sensitivity compared with the foam without filler. The yield strength, flow stress as well as energy absorbing capacity of the AlSi 12 foam with silicate rubber filler increase with increasing in strain rate. It is also indicated that with increase of the cell size, more increase in the dynamic yield strength and the flow stress take place in the AlSi12 foam filled with silicate rubber.The effects of mixing a big cell size with a small cell size in different size and volume proportion on mechanical properties of the open-cell aluminum were investigated by experimental research and using finite element simulation. Firstly, the models of the aluminum foams with different pore structure were established by the finite element method. The influence of the variation in pore structure on the mechanical properties of the aluminum foams was simulated and corresponding parameters were obtained. Then, the aluminum foams with the corresponding pore parameters were prepared by the infiltration process. And the quasi-static compressive experiments were conducted on the materials in order to check the FEA simulative results. The experimental and the FEA simulative results both indicate that the strength and stiffness of the open-cell aluminum foams are increased obviously by the pore structure consisting of the big cell...