Study On The Foamed Aluminum Produced By Rare-earth Hydride Foaming Agent

Foamed aluminum is a new kind of metal material with special structural and functional composite porous. It could be used in various fields, such as transportation, architecture, machine, metallurgy, chemical industry, electro-communication and aerospace. Based on melt foaming method, this paper studied using REH instead of TiH2 as foaming agent and scrap aluminum instead of homozygosis aluminum or aluminum alloy to fabricate aluminum foam. It is believed this study provide a promising pathway for production of foamed aluminum.The primary constituent of REH is LaH2.43 by the component analysis. Then the decomposition temperature of REH was defined by the thermal gravimetric analysis (TG and DSC). The dynamic equation of rare-earth hydride, reaction order and activation energy was obtained based on the theory of Arrhenius Equation and Freeman-Carroll.During the experiment, viscosity-increasing agent was not used because raw material was scrap aluminum. Optimal technic parameters of foaming process was determined:the quantity of foaming agent was 2.0-2.5 percent (mass), the foaming temperature was 750±10℃. Aluminum foam with uniform pore was also fabricated with the mixture of REH and TiH2. When the quantity of foaming agent was 2.0 percent (mass), REH account for 75-85 percent and the foaming temperature was 710℃-720℃. Furthermore, the distribution of La element in foamed aluminum was tested. Gravity segregation of La in foamed aluminum was explained.Compress performance was tested. Results showed that the compression mode of foamed aluminum was completed through bending, puckering and fracturing processes. The compressive stress-strain(σ-ε)curve had a long ductility stress flat roof. Analysis of the compress curve showed good energy-absorbing rate. The peak value of energy-absorbing rate was greater than 80 percent. When strain equaled 0.5, the energy-absorbing rate can over 60 percent.