Nanoscale phase separation in a fcc-based CoCrCuFeNiAl0.5 high-entropy alloy

被引：218

作者：

Xu, X. D. ^{[1
]}

Liu, P. ^{[1
]}

Guo, S. ^{[2
]}

Hirata, A. ^{[1
]}

Fujita, T. ^{[1
]}

Nieh, T. G. ^{[3
]}

Liu, C. T. ^{[2
]}

Chen, M. W. ^{[1
,4
]}

机构：

[1] Tohoku Univ, WPI Adv Inst Mat Res, Sendai, Miyagi 9808577, Japan

[2] City Univ Hong Kong, Ctr Adv Struct Mat, Kowloon, Hong Kong, Peoples R China

[3] Univ Tennessee, Dept Mat Sci & Engn, Knoxville, TN 37996 USA

[4] Shanghai Jiao Tong Univ, Sch Mat Sci & Engn, State Key Lab Met Matrix Composites, Shanghai 200030, Peoples R China

来源：

ACTA MATERIALIA | 2015年 / 84卷

基金：

美国国家科学基金会; 中国国家自然科学基金;

关键词：

Phase separation; High-entropy alloy; Cs-corrected TEM; Atom probe tomography; Lattice distortion; MICROSTRUCTURE CHARACTERIZATION; SINGLE-PHASE; STABILITY; PLASTICITY; ELEMENTS;

D O I：

10.1016/j.actamat.2014.10.033

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

Nano-scale phase separation is reported in a nominal single-phase, high-entropy alloy (HEA), which was characterized using scanning transmission electron microscopy (STEM) combined with atom probe tomography (APT). Despite the fact that X-ray diffraction exhibits a single face-centered-cubic (fcc) phase feature of the as-cast alloy prepared by melt spinning, selected area electron diffraction reveals weak L1(2) ordering in the as-spun alloy. High-resolution STEM shows the presence of two coherent nanophases with distinct L1(2) and fcc structures, coupling with compositional segregations. The ordering of the L1(2) domains is enhanced after annealing at 500 degrees C. Electron energy loss spectroscopy and APT analyses reveal that the L1(2) nano-phase is enriched with Fe, Co, Cr and Ni, while the fcc domains are a Cu-rich phase. The nano-scale phase separation can effectively minimize the lattice distortions caused by the atomic size difference in the constituent elements, which may offer structural insights into the unusual mechanical behavior and phase stability of fcc HEA. (C) 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

引用

页码：145 / 152

页数：8

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