About this Abstract |
Meeting |
2023 TMS Annual Meeting & Exhibition
|
Symposium
|
Scandium Extraction and Use in Aluminum Alloys
|
Presentation Title |
E-31: Effect of Sc on Surface Recrystallization of AA7050 Extrusions |
Author(s) |
Keaton Schmidt, Tom Wood, Timothy James Langan, Paul G. Sanders |
On-Site Speaker (Planned) |
Keaton Schmidt |
Abstract Scope |
Extrusion processes utilize high temperatures and strains that can result in undesirable surface microstructures. During post-extrusion heat treating, aluminum can exhibit surface recrystallization known as peripheral coarse grains (PCG) formation, which can reduce fatigue strength and corrosion resistance. Additions of Sc to AA7050 can produce nano-sized dispersoids with Sc cores and Zr shells that resist recrystallization. A baseline 7050 billet (Zr only) and two Sc additions (0.02 and 0.05 wt%) extruded to assess dispersoid effects on PCG formation at varying surface strains after standard heat treating. The 0.02 wt% Sc addition reduced PCG by 15% at low strains of 8 to 9.5 and 50% in regions where strain reached 10 to 12.5. The alloy with 0.05 wt% Sc prevented PCG formation at the lowest strains and reduced the volume of PCGs by up to 90% in high strain regions. While adding 0.1wt% Sc to an alloy costs about $2, this additional cost may be offset by improving the quality of extrusions and reducing processing costs with different extruding parameters. |
Proceedings Inclusion? |
Planned: Light Metals |