Investication Of The Physical And Mechanical Properties Of Open-cell Aluminum Foams

Aluminum foams have unique properties that make them useful in a number of potential applications. In this paper open-cell alminum alloy foams with basically controllable pore structure and uniform distributed pore were prepared by means of infiltrating process. Properties of tensile,electrical conductivity and electromagnetic shielding effectiveness were investigated.Firstly,the tensile experiments of the pure Al foams and the Al-Si alloy foams were carried.The results show that both the pure Al foams and Al-Si alloy foams contain elastic deformation,plastic deformation and crack deformation during tensile. The Young's modulus and tensile strength rised with the increase of relative density,and the influence of the pore size can be ignored.The metallic struts tear to break off one by one during tensile experiments.Secondly,the electrical conductivity of of the pure Al foams and the Al-Si alloy foams have been studied.The results show that the electrical conductivity of the aluminum alloy foams mount up with the increase of the relative density as a power function.The influense of the cell wall material's electrical conductivity will be weaker with lower relative density.We also studied the open-cell aluminum foams' electromagnetic shielding effectiveness. The results show that the shielding effectiveness of aluminum foam is from 25 dB to 75dB while the frequency is between 50 and 1050MHz,and it rise with the increase of the relative density.When the frequency is between 50 and 850 MHz, the bigger of the aluminum foam cell size the better of shielding effectiveness it will have, and the cell size effectiveness can be ignored if the frequency is higher than 850MHz.The electromagnetic shielding effectiveness of aluminum foam arise with the increase of the thickness of the sample when the frequency is between 50 and 700MHz, and if the frequency is higher than 700MHz the thickness effectiveness can been ignored.