Unexpected nucleation mechanism of T1 precipitates by Eshelby inclusion with unstable stacking faults
Shuo Wang , Junsheng Wang , Chengpeng Xue , Xinghai Yang , Guangyuan Tian , Hui Su , Yisheng Miao , Quan Li , Xingxing Li
Materials Genome Engineering Advances ›› 2024, Vol. 2 ›› Issue (2) : 33
Unexpected nucleation mechanism of T1 precipitates by Eshelby inclusion with unstable stacking faults
Aluminum-lithium (Al-Li) alloy is one of the most promising lightweight structural materials in the aeronautic and aerospace industries. The key to achieving their excellent mechanical properties lies in tailoring T1 strengthening precipitates; however, the nucleation of such nanoparticles remains unknown. Combining atomic resolution HAADF-STEM with first-principles calculations based on the density functional theory (DFT), here, we report a counterintuitive nucleation mechanism of the T1 that evolves from an Eshelby inclusion with unstable stacking faults. This precursor is accelerated by Ag-Mg clusters to reduce the barrier, forming the structural framework. In addition, these Ag-Mg clusters trap the free Cu and Li to prepare the chemical compositions for T1. Our findings provide a new perspective on the phase transformations of complex precipitates through solute clusters in terms of geometric structure and chemical bonding functions.
Al alloy / DFT / nucleation / phase tranformation / precipitation
2024 The Authors. Materials Genome Engineering Advances published by Wiley-VCH GmbH on behalf of University of Science and Technology Beijing.
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