Abstract
Foamed Aluminum (highly porous Aluminum) was fabricated by powder processing technology. Aluminum (pure Al or Al–7Si alloy) and titanium hydride (TiH2) powders were mixed to prepare a precursor. The Al(–7Si)/TiH2 precursor was consolidated by three different methods (cold compaction, hot compaction and hot extrusion). The hot compaction and hot extrusion temperatures were 673 and 773 K, respectively. The cold compaction pressures were 450 MPa and 800 MPa, and the hot compaction pressure was 160MPa. The Al(–7Si)/TiH2 precursor was heated in an infrared furnace to melt aluminum and to decompose TiH2, which resulted in the H2 gas generation in molten aluminum. In this work, effects of some processing parameters (heating temperature, heating duration, heating rate and aluminum powder composition) on the foaming behavior were investigated. Heating temperature should be in an adequate range. When the heating temperature was low, the precursor did not expand sufficiently. On the other hand, when the heating temperature was high, the precursor shrunk rapidly. The heating rate did not affect the foaming behavior significantly within the present experimental ranges (0.12~0.5K·s−1). When the Al–7Si/TiH2 precursor was heated, the maximum expansion was sustained for a certain period of time, whereas the Al/TiH2 precursor shrunk rapidly.
