Unique hybrid precipitate structures forming in an Al-Cu-Mg-Si alloy

JOURNAL OF ALLOYS AND COMPOUNDS

卷:826

Article

Gazizov, Marat¹  Marioara, Calin Daniel²  Friis, Jesper^2,3  Wenner, Sigurd^2,3  Holmestad, Randi³  Kaibyshev, Rustam¹ 

[1] Belgorod State Univ, Belgorod 308015, Russia

[2] SINTEF Ind, Mat & Nanotechnol, N-7465 Trondheim, Norway

[3] Norwegian Univ Sci & Technol NTNU, Dept Phys, N-7491 Trondheim, Norway

关键词: Metals and alloys;    Atomic scale structure;    Transmission electron microscopy;    TEM;    Computer simulations;   

DOI  :  10.1016/j.jallcom.2020.153977

来源: Elsevier

【 摘 要 】

Crystal structures of hybrid precipitates have been analysed by atomic-resolution scanning transmission electron microscopy in an aged Al-Cu-Mg-Si alloy. A new unique hybrid precipitate (UHP) has been found as rod-shaped discrete particles along < 100 >(Al) in bulk aluminium matrix. The UHP consists of a core with local 4-fold symmetry surrounded by GPB zone unit pillars often combined with monoatomic Cu layers in fcc-Al matrix. A certain atomic configuration fragment of the UHP structure is often seen to inter-grow with other hybrid precipitate complexes consisting of diverse phases belonging to the Al-Cu-Mg-Si and Al-Cu alloy systems. Density functional theory (DFT) calculations performed on a discrete UHP showed that the most energetically favorable core configuration resembles a beta ''-eye from the Al -Mg-Si system rotated 45 degrees C in respect to its usual orientation with the fcc-Al matrix. (C) 2020 Elsevier B.V. All rights reserved.

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