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Aluminum foam has been produced by sintering and dissolution processes using NaCl powders as a space holder. In this research, glycerin is used as a novel lubricant along with acetone. The effects of the processing parameters including compacting pressure, sintering temperatures (620, 640 and 650 °C), size, and volume fraction of the space holder, on the physical and mechanical properties of the produced foams have been investigated. Due to segregation of the Al and NaCl powders at high compaction pressures, spalling of Al foams was observed. Meanwhile, adding small amounts of acetone and glycerin to the mixture ensures homogeneity and prevents segregation of dissimilar powders at varying pressure. Moreover, the addition of glycerin provides an improved homogenous stress distribution within the produced foams during mechanical testing, which in turn halts crack propagation. Meanwhile, an alternative technique to remove NaCl particles during the dissolution stage has been proposed. The results showed that high quality foams were successfully produced under a compaction pressure range of 250–265 MPa and sintering temperature of 650 °C. more...

In the present study, fabrication of the aluminum (Al) foam through sintering and dissolution process and effect of space holder (NaCl) mean size on compressive behavior of metallic foam has been investigated. Due to improper cold bonding between Al particles in low compaction pressure spalling of the foam was observed. Appropriate compacting pressure and sintering temperature of the compacts resulted in production of high quality Al foams. SEM was used to characterize the morphology of produced Al foam and mechanical behavior of produced foams was evaluated using compression test machine. The results show that open-cell Al foam free from cracks was obtained and an increase in NaCl mean size resulted in increases of the compressive strength, Young modulus and plateau stress of the stress-strain curves. more...