Dynamic precipitation, segregation and strengthening of an Al-Zn-Mg-Cu alloy (AA7075) processed by high-pressure torsion
Abstract
Combining transmission Kikuchi diffraction, high resolution transmission electron microscopy and atom probe tomography, we investigated an Al-Zn-Mg-Cu alloy (AA7075) processed by high-pressure torsion (HPT) at room temperature and 200 °C, with an objective to reveal the deformation-induced precipitation and segregation of elements at grain boundaries, and to study their appearance at different processing regimes. Although HPT processing at the two temperatures both induced the formation of ŋ phase, ŋ precipitates formed at the two temperatures have different chemical compositions. The increase of the HPT processing temperature increased significantly segregation of Mg and Cu at grain boundaries. The HPT-induced segregation and decomposition of the alloy have a significant effect on its mechanical strength. Our results open a way for achieving advanced mechanical properties in nanostructured metals and alloys by designing their precipitation and segregation through the control of SPD processing regimes.
- Publication:
-
Acta Materialia
- Pub Date:
- January 2019
- DOI:
- 10.1016/j.actamat.2018.09.060
- Bibcode:
- 2019AcMat.162...19Z
- Keywords:
-
- Dynamic precipitation;
- Segregation;
- Strengthening;
- Al-Zn-Mg-Cu alloy;
- High-pressure torsion