Compaction of amorphous aluminum alloy powder by direct extrusion and equal channel angular extrusion

Al89Gd7Ni3Fe1 alloy powder produced by gas atomization was consolidated using equal channel angular extrusion (ECAE) and direct extrusion. The powder particle size was below 30 μm and the as-received powder was ∼70-80% amorphous. ECAE compaction of loose powder was conducted at 200 °C. The microstructure of the compacted material was studied after different levels of ECAE deformation, which allowed analysis of the mechanism of particle interactions, deformation and bonding during different stages of consolidation. Direct extrusion compaction was conducted at 210, 250, 400, and 450 °C. After compaction at 210 °C, the material was about 70% amorphous and it had 98-99% of the theoretical density. A fully dense alloy with a nanocrystalline structure (grain size ∼700 nm) was produced after extrusion at 450 °C. Extrusion at 250 and 400 °C led to poor consolidation of the powder due to formation of brittle intermetallic phases with volume fraction of about 40%.