Publication
Title
“Branched” structural transformation of the L1₂-Al₃Zr phase manipulated by Cu substitution/segregation in the Al-Cu-Zr alloy system
Author
Abstract
The effect of Cu on the evolution of the Al3Zr phase in an Al-Cu-Zr cast alloy during solution treatment at 500 °C has been thoroughly studied by combining atomic resolution high-angle annular dark-field scanning transmission electron microscopy, energy-dispersive X-ray spectroscopy and first-principles calculations. The heat treatment initially produces a pure L12-Al3Zr microstructure, allowing for about 13 % Cu to be incorporated in the dispersoid. Cu incorporation increases the energy barrier for anti-phase boundary (APB) activation, thus stabilizing the L12 structure. Additional heating leads to a Cu-induced “branched” path for the L12 structural transformation, with the latter process accelerated once the first APB has been created. Cu atoms may either (i) be repelled by the APBs, promoting the transformation to a Cu-poor D023 phase, or (ii) they may segregate at one Al-Zr layer adjacent to the APB, promoting a transformation to a new thermodynamically favored phase, Al4CuZr, formed when these segregation layers are periodically arranged. Theoretical studies suggest that the branching of the L12 transformation path is linked to the speed at which an APB is created, with Cu attraction triggered by a comparatively slow process. This unexpected transformation behavior of the L12-Al3Zr phase opens a new path to understanding, and potentially regulating the Al3Zr dispersoid evolution for high temperature applications.
Language
English
Source (journal)
Journal of materials science & technology
Publication
2024
ISSN
1005-0302
DOI
10.1016/J.JMST.2023.11.015
Volume/pages
185 (2024) , p. 186-206
ISI
001154261100001
Full text (Publisher's DOI)
Full text (open access)
The author-created version that incorporates referee comments and is the accepted for publication version Available from 02.07.2024
Full text (publisher's version - intranet only)
UAntwerpen
Faculty/Department
Research group
Publication type
Subject
Affiliation
Publications with a UAntwerp address
External links
Web of Science
Record
Identifier
Creation 17.01.2024
Last edited 11.04.2024
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