Abstract
The effects of solidification rates and solutionizing temperatures on V-phase (Al8Cu4Sc) nanoprecipitate formation and subsequent mechanical properties in a cast Al-4.5Cu-0.3Mg-0.4Ag-0.3Sc (wt%) alloy are evaluated. After solutionizing, Ω-Al2Cu precipitates are formed upon aging at 185 °C and then transformed into Al8Cu4Sc V-phase precipitates at 400 °C, showing high coarsening resistance. Avoiding Al8-xCu4+xSc W-phase precipitation during solidification is crucial, as this phase reduces the concentration of Cu and Sc available in the matrix for Al2Cu Ω-precipitation at 185 °C and the subsequent final formation of V-precipitates at 400 °C, affecting microhardness at ambient temperature and creep strength at 400 °C. Solutionizing temperatures between 580 and 600 °C dissolve the undesirable W-phase but form large stable θ-Al2Cu phases, which also scavenge Cu. Furthermore, the W-phase was observed both under relatively fast solidification in a graphite mold and very slow solidification in a furnace, and the microhardness was similar under the two casting conditions. Similarly, adding 0.15Si wt% does not impact the mechanical properties of the alloy. These findings suggest that Al-Cu alloys with V-phase precipitates have promising potential for high-temperature applications, although further study of the processing techniques is necessary to fully utilize their capabilities.
| Original language | English |
|---|---|
| Article number | 121567 |
| Journal | Acta Materialia |
| Volume | 301 |
| DOIs | |
| State | Published - Dec 1 2025 |
| Externally published | Yes |
Funding
This work made use of the MatCI facility which receives support from the MRSEC Program ( DMR-2308691 ) of the Materials Research Center at Northwestern University . This work made use of the EPIC facility ( RRID: SCR_026361 ) of Northwestern University’s NUANCE Center , which has received support from the SHyNE Resource ( NSF ECCS-2025633 ), the IIN , and Northwestern's MRSEC program ( NSF DMR-2308691 ). The authors thank Dr. Taylor Cain for his suggestions on solidification experiments, processing impacts, and review of manuscript. The authors would also like to thank Drs. Gang Liu, Hang Xue, and Chong Yang (State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University) for a useful discussion concerning processing conditions of Al-Cu-Mg-Ag-Sc alloys; they are also grateful to Mr. David Weiss (Vision Materials) and Dr. Taylor Cain (ARL) for useful discussions on aluminum alloy processing. IEC and CNE were funded by DEVCOM Army Research Laboratory (ARL) via award W911NF-21–2-0199 . The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the official policies, either expressed or implied, of the Army Research Laboratory of the U.S. Government. The U.S. Government is authorized to reproduce and distribute reprints for Government purposes notwithstanding any copyright notation herein. IEC and CNE were funded by DEVCOM Army Research Laboratory (ARL) via award W911NF-21–2-0199. The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the official policies, either expressed or implied, of the Army Research Laboratory of the U.S. Government. The U.S. Government is authorized to reproduce and distribute reprints for Government purposes notwithstanding any copyright notation herein. This work made use of the MatCI facility which receives support from the MRSEC Program (DMR-2308691) of the Materials Research Center at Northwestern University. This work made use of the EPIC facility (RRID: SCR_026361) of Northwestern University's NUANCE Center, which has received support from the SHyNE Resource (NSF ECCS-2025633), the IIN, and Northwestern's MRSEC program (NSF DMR-2308691). The authors thank Dr. Taylor Cain for his suggestions on solidification experiments, processing impacts, and review of manuscript. The authors would also like to thank Drs. Gang Liu, Hang Xue, and Chong Yang (State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University) for a useful discussion concerning processing conditions of Al-Cu-Mg-Ag-Sc alloys; they are also grateful to Mr. David Weiss (Vision Materials) and Dr. Taylor Cain (ARL) for useful discussions on aluminum alloy processing.
Keywords
- Aging
- Aluminum alloys
- Creep
- Mechanical properties
- Precipitation strengthening