Research On Strengthening Process And Mechanism Of High Porosity Open-pore Aluminum Foam

Foamed aluminum is a new type of engineering material with both structural and functional properties, the preparation method of high porosity open-pore aluminum foam is mainly based on the investment casting method of polyurethane foam as matrix. This method has the following problems: 1) The strut of the aluminum foam samples prepared by this method was thin and the strength was lower. 2)The preparation of aluminum foam sample with larger pore density was difficult. 3)The preparation of large size of foamed aluminum sample was difficult using this method. 4) Aluminum open-pore foam structure theory is not perfect. To solve above problems, this paper try to make it easy to fill the mold by thickening the strut of reticulated polymer foam to increase the strength of open-pore aluminum foam, and complete the open-pore foam structure theory.Firstly, the structure of open-pore foams was investigated in theoretical research. The actual structure parameters of reticulated polymer foam was counted. Diamond model and tetradecahedral model were chosen according to results of the analysis. Similarities and differences of these two models were compared using geometric methods and the orientation matrix was constructed during this process. Based on the topological relations of reticulated polymer foam, the formula of the relative density and diameter of strut of open-pore foams was obtained combining the aforementioned results of the analysis and the mathematical derivation, which the contribution effects of strut thickening to relative density increasing was analyzed basing on; Secondly, the experimental research on strut thickening of preparation of open-pore aluminum foam was conducted. By controlling the thickness of strut of polyurethane precursor foam, thickness adjustment of strut of open-pore aluminum foam sample was achieved. Polyurethane foam samples and open-pore aluminum foam samples with different relative densities were successfully prepared. And then,structural analysis of polymer foam and open-pore aluminum foam were conducted;Finally, the simulation study of polyurethane foam samples and open-pore aluminum foam samples was conducted. Both the relationship between pore’s diameter and the srtut’s length and the relationship between diameter length ratio of the strut and relative density were calculated using UG software. The effect of open-pore aluminum foam compression performance of diameter length ratio and length of the strut were separately analyzed using Deform-3D software.Theoretical studies shown that it is appropriate to select diamond model as the model of open-pore foam structure and the contribution effects of strut thickening to relative density increasing is related to the diameter of strut itself; Experimental studies shown that Φ68mm*10mm open-pore aluminum foam of pore density of ρP=10ppi and a rang of porositis of 78%≤p≤91% could be prepared using the method of thickening strut, however, there is some defects such as broken strut and incompleteness in which; Simulation studies shown that both increasing the diameter length ratio and reducing the length of the strut could improve the compressive strength of open-pore aluminum foam.