Characterization of Al Skeletal Structures Fabricated by Ultrasonic Powder Consolidation

Skeletal aluminum structures were fabricated by ultrasonic powder consolidation (UPC) of NaCl15masspct Al and NaCl20masspct Al composites at 723K and 773K (450 degrees C and 500 degrees C) for 4seconds and subsequent leaching of the spacer NaCl from the composites by dissolution in water. Ultrasonically consolidated skeletal specimens withstood ultrasonic washing in water, whereas control specimens fabricated under identical conditions, but without ultrasonic vibration, were severely disintegrated. Scanning electron microscopy and mass analysis indicated full removal of NaCl from the UPC specimens. Scanning transmission electron microscopy confirmed full densification and metallurgical bonding in the cell walls of UPC specimens consolidated at 773K (500 degrees C). The mechanisms of rapid densification and bonding in the Al cell walls were elucidated based on microstructural changes during UPC.