Microstructure of Powder and Conventionally Processed 7075 Aluminum Alloy.

Aluminum alloy powder of the 7075 composition was consolidated by warm upset and extrusion. Commercial cast and wrought material was also extruded to serve as a control. Results of varying the length of time at solution treatment temperature indicate that the powder material is far less resistant to recrystallization than the conventional material. Optical and transmission electron microscopy revealed that after identical post-extrusion solution treatments the substructure formed during extrusion throughout the commercial material was stable while the powder material retained substructure only near the edges of the rectangular extrusion and had undergone complete recrystallization toward the center. Author