On the formation of anti-phase boundaries and interphase boundaries in Al3Zr precipitates of Al-Cu-Zr alloy studied at atomic scale

The nature and orientation of anti-phase boundaries (APBs) and interphase boundaries in Al3Zr precipitates of the Al-Cu-Zr alloy were investigated by aberration-corrected scanning transmission electron microscopy (STEM). Two groups of APBs ({100} and {110}) are identified. The {100} APBs are in the majority, while the {110} APBs are for the first time observed in the Al3Zr precipitate. Both kinds of APBs are associated with a displacement vector of a/2 < 110 > in corresponding planes. Besides, two different L1(2)/D0(23) interfaces (in phase and anti-phase relationships) are formed in the Al3Zr precipitate, which is mainly caused by the activation of multiple APBs in different planes. It is clarified that the APBs play an important role in the L1(2)-D0(23) transformation. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

The nature and orientation of anti-phase boundaries (APBs) and interphase boundaries in Al3Zr precipitates of the Al-Cu-Zr alloy were investigated using aberration-corrected STEM. Two groups of APBs ({100} and {110}) were identified, with {100} APBs being more common and {110} APBs observed for the first time. Two different L1(2)/D0(23) interfaces were formed in the Al3Zr precipitates, mainly due to the activation of multiple APBs in different planes, highlighting the important role of APBs in the L1(2)-D0(23) transformation.