The enhanced theta-prime (θ′) precipitation in an Al-Cu alloy with trace Au additions

被引：77
作者：
Chen, Yiqiang [1 ]
Zhang, Zezhong [1 ]
Chen, Zhen [2 ]
Tsalanidis, Amalia [1 ]
Weyland, Matthew [1 ,3 ]
Findlay, Scott [2 ]
Allen, Leslie J. [4 ]
Li, Jiehua [5 ]
Medhekar, Nikhil V. [1 ]
Bourgeois, Laure [1 ,3 ]
机构：
[1] Monash Univ, Dept Mat Sci & Engn, Clayton, Vic 3800, Australia
[2] Monash Univ, Sch Phys & Astron, Clayton, Vic 3800, Australia
[3] Monash Univ, Monash Ctr Electron Microscopy, Clayton, Vic 3800, Australia
[4] Univ Melbourne, Sch Phys, Melbourne, Vic 3010, Australia
[5] Univ Montana, Chair Casting Res, A-8700 Leoben, Austria
来源：
ACTA MATERIALIA | 2017年 / 125卷
基金：
澳大利亚研究理事会;
关键词：
Aluminium alloy; Nucleation; Solute formation enthalpy; Precipitate growth; Scanning transmission electron microscopy; TRANSMISSION ELECTRON-MICROSCOPY; 1ST-PRINCIPLES CALCULATIONS; INTERFACIAL SEGREGATION; PHASE; ALUMINUM; DISPLACEMENT; SYSTEM; STRAIN; FIELD; SUPERALLOY;
D O I：
10.1016/j.actamat.2016.12.012
中图分类号：
T [工业技术];
学科分类号：
08 ;
摘要：
Linking the atomic level kinetic precipitation pathways induced by elemental additions to the resulting microstructure is fundamentally desirable for the design of new classes of light alloys. Aberration corrected scanning transmission electron microscopy (AC-STEM) and first principles calculations were used to investigate the influence of trace Au (200 ppm) additions on precipitation in an Al-Cu-Au alloy. These Au additions resulted in a significant enhancement of the low-temperature age hardening, which was demonstrated to be associated with accelerated precipitate nucleation and growth. Atomic resolution annular dark field (ADF) imaging showed the clearly reduced critical length and thickness of theta' precipitates with Au additions, therefore accelerating the nucleation of theta'. Agglomerated Au clusters were observed in theta' precipitates, which were demonstrated to correspond to a localised energetically favourable state. These observations have been explained through first-principles calculations and relevant thermodynamic modelling. This work provides a potential way to refine the alloy microstructure for improving the mechanical behaviour of light alloys. (C) 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
引用
收藏
页码：340 / 350
页数：11
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