Effects of Pore Nucleation, Growth and Solidification Mode on Pore Structure and Distribution of Lotus Type Porous Copper

摘要

Abstract Effects of pore nucleation, growth and solidification mode of matrix on pore structure and distribution of lotus-type porous Cu fabricated by Gasar process were investigated. The results showed that it was difficult to obtain an ordered pore structure when the matrix contained equiaxed grain. An ordered pore structure, with increased pore length and circularity, could be obtained when the matrix consisted of columnar grains. The pore distribution moved from the grain boundaries to the interior of grain with increasing gas pressure. It was further noticed that the average pore diameter decreased and the pore density increased due to decreased activation energy and increased rate of nucleus formation. Due to slight depressions at grain boundaries of the solid/liquid interface, the pore nucleation was favored at grain boundaries and thus the average pore diameter in grain boundaries was larger than that in grains.