Study Of The Fabricating Process And The Properties Of Open-cell Aluminum Foam With High Porosity

Aluminum foam is a new kind of structural and functional material with light-weight, high specific strength and stiffness, good sound absorption and energy absorption, heat dissipation and electromagnetic shielding properties, so it has broad application prospects in aerospace, auto and civil industries. In this paper, the process for fabricating high-porosity open-cell aluminum foam with different parent materials, different pore sizes and different relative density by infiltrating casting using soluble gypsum mould was studied, and the quasi-static compressive experiments and electric conductivity on the open-cell aluminum foam were studied.The fabricating process of gypsum mould was studied. The testing results showed that the eligible gypsum mould could be made with gypsum powder,MgSO4,bauxite and water, different aperture sizes of polymeric reticular sponge which was used as mother plate in this process. The compressive strength and water-soluble of the gypsum mould can be increased by adding MgSO4. When the content of MgSO4 is 20%, the highest compressive strength of the gypsum mould can be reached. The bauxite could increase the compressive strength, resistance the heating shrinkage and cracking tendency of the gypsum mould.The process of fabricating high porosity open-cell aluminum foam with infiltrating casting was studied. The experimental results result showed that the main parameters in this process were the mold's preheat temperature, the temperature of liquid aluminum alloy and infiltrating pressure. The porosity of the open-cell aluminum foams prepared in this paper was between 85% and 96%.The quasi-static compression test of the aluminum foam was carried out to study the parameters changes of the aluminum foam how to affect the compressive mechanical properties and energy absorption characteristics. The testing results showed that three deforming regions such as elasticity region, plastic collapsing region and densification region are observed in the compressive stress-strain curves of the open-cell ZL101 and ZL102 aluminum foams, and the plastic plateau region of the curves were characterized by distinct fluctuations in fluid stress. The yield strength, Young's modulus and fluid stress of the aluminum foams increased with the low-density open-cell aluminum foams'relative density increased. The aperture sizes of the open-cell aluminum foam could also affect the yield strength and Young's modulus. The mechanical properties of the aluminum foam were proportional to the parent materials. The ideal energy-absorbing efficiency of the aluminum foam was related with the stress-strain curve's shape, when the stress-strain curve was smoother, the ideal energy-absorbing efficiency was higher.Finally, the electrical conductivity of the open-cell aluminum foam was tested by the"four points"method. The results showed that: the electrical conductivity of the low-density open-cell aluminum foam increased with the increasing of their relative density, the changes law between the relative electrical conductivity and the relative density could be described by the exponential function, and the exponential number increased as the pore size decreased. The electrical conductivity of the aluminum foam was connected with the parent materials'.