Optimization of Pore Walls Microstructure in Open Cell Aluminum Foams Utilizing Self-Propagating Reaction

抄録

The Al(H₂PO₄)₃ doped with thermite as the space holder is prepared for aluminum foams during powder metallurgy process. The pore walls of aluminum foams are covered with the in-situ synthesized residual phosphates produced from Al(H₂PO₄)₃ after the self-propagating reaction in space holder. Influences of the thermite content dispersed in space holder on both phase transformation and the coating layers microstructure of pore walls are investigated. The results suggest that the added thermite could optimize the microstructure of pore walls coating layers even if the space holder sintered at the lower furnace temperature, due to the released larger energy from thermite reaction would increase the local reaction temperature for Al(H₂PO₄)₃. The melted loose coating layers of the pore walls may shrink and lead to the higher porosity of aluminum foams can be obtained.

Fig. 5 (a) The formed local micropore structure in specimen 3#, and the coating layers microstructure of the pore wall in (b), (c), (d) corresponding to the 1#, 2#, 4#, respectively.