Preparation Of ZA Alloy Foam And Its Composite Material And Study On Its Mechanical Damping Properties

The study of metal foam mainly focuses on aluminum based foam and nickel based foam, but as damping materials zinc based foam has a better performance than the former. In this paper, ZA alloy has been selected as the base material and ZA alloy foam has been prepared by vacuum infiltration casting process. The effects of the technological factors on the infiltration length have been systematically studied. Then the rosin and the paraffin wax have been infiltrated into the ZA alloy foam respectively by infiltration method, so the new composite materials with the high damping properties have been formed and its mechanical damping properties have also been studied. The results show that:(1) The infiltration length is influenced by the size of particles, the preheated temperature, infiltrating temperature of ZA alloy-melt and infiltrating pressure. The size of particles is more effective than others factors. The optimal process parameters of Zn-27%Al, Zn-22%Al and Zn-5%Al are determined.(2) The packing density of salt particles is a direct factor to porosity. The reference value of packing density under which we can obtain the maximum porosity of Zn-27%Al foam is given.(3) The compressive strength of ZA alloy foam increases with the increase of the relative density and increases with the increase of aluminum content. The compressive strength of the composite increases as the paraffin wax and the rosin inside the composite carry load.(4) The damping mechanism of ZA alloy foam and its composite is damping disfigurement. The internal friction of ZA alloy foam and its composite increases with the decrease of aperture and increases with the increase of viscosity of infiltrating materials.(5) ZA alloy foam with rare earth Ce or La additives have been fabricated by the vacuum infiltration casting,the addition of Ce and La into the Zn-22%Al alloy foam can refine microstructure and improve the damping capacity as well. The best modification effect and highest damping capacity can be obtained at 0.3wt%RE.