Complex Precipitation Sequences of AI-Cu-Li-（Mg） Alloys Characterized in Relation to Thermal Ageing Processes

The A1-Cu-Li-（Mg） alloy is a high-performance lightweight material strengthened by complex coexisting precipitates that form in the alloy upon thermal ageing. Using high-resolution （scanning） transmission electron microscopy in association with first-principles energy calculations, we systematically...

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Published in金属学报：英文版 no. 1; pp. 94 - 103
Main Author Zhen Gao Jiang-Hua Chen Shi-Yun Duan Xiu-Bo Yang Cui-Lan Wu
Format Journal Article
LanguageEnglish
Published 2016
Subjects
分析
金属学
金属物理学
金相学
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Summary:The A1-Cu-Li-（Mg） alloy is a high-performance lightweight material strengthened by complex coexisting precipitates that form in the alloy upon thermal ageing. Using high-resolution （scanning） transmission electron microscopy in association with first-principles energy calculations, we systematically studied the complex coexisting precipitates in the alloys and correlated their precipitation sequences with thermal ageing processes applied. The principal results are the following： （1） eight types of precipitates can be observed in the alloy; （2） of these precipitates, the Tl-phase is most stable. The S-phase precipitates with segregated Li atoms at their interfacial edges are unexpectedly more stable than the a-phase; （3） the Tl-phase has a characteristic precursor that plays the key role in its nucleation and growth.
Bibliography:AI-Cu-Li alloy; Electron microscopy; Ageing; Precipitation; Strength
The A1-Cu-Li-（Mg） alloy is a high-performance lightweight material strengthened by complex coexisting precipitates that form in the alloy upon thermal ageing. Using high-resolution （scanning） transmission electron microscopy in association with first-principles energy calculations, we systematically studied the complex coexisting precipitates in the alloys and correlated their precipitation sequences with thermal ageing processes applied. The principal results are the following： （1） eight types of precipitates can be observed in the alloy; （2） of these precipitates, the Tl-phase is most stable. The S-phase precipitates with segregated Li atoms at their interfacial edges are unexpectedly more stable than the a-phase; （3） the Tl-phase has a characteristic precursor that plays the key role in its nucleation and growth.
21-1361/TG
ISSN:1006-7191
2194-1289