Effects of AL addition on microstructure and mechanical properties of AlxCoCrFeNi High-entropy alloy

被引:312
作者
Yang, Tengfei [1 ]
Xia, Songqin [2 ]
Liu, Shi [2 ]
Wang, Chenxu [1 ]
Liu, Shaoshuai [1 ]
Zhang, Yong [2 ]
Xue, Jianming [1 ]
Yan, Sha [1 ]
Wang, Yugang [1 ]
机构
[1] Peking Univ, Ctr Appl Phys & Technol, State Key Lab Nucl Phys & Technol, Beijing 100871, Peoples R China
[2] Univ Sci & Technol Beijing, State Key Lab Adv Met & Mat, Beijing 100083, Peoples R China
来源
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING | 2015年 / 648卷
基金
中国博士后科学基金; 中国国家自然科学基金;
关键词
High-entropy alloy; Transmission electron microscopy; Mechanical properties; Microstructure; ELASTIC-MODULUS; HARDNESS;
D O I
10.1016/j.msea.2015.09.034
中图分类号
TB3 [工程材料学];
学科分类号
0805 ; 080502 ;
摘要
The effects of Al on microstructure and mechanical properties of AlxCoCrFeNi (x=0.1, 0.75 and 1.5) high-entropy alloys were systematically studied by using various characterization methods. It was found that the crystalline structure of AlxCoCrFeNi high-entropy alloy varies markedly with Al content, which changes from the initial single face-centered cubic (fcc) to fcc plus ordered body-centered cubic (bcc) structure (B2) and then to a duplex bcc structure (A2+B2) as the Al content is increased. The chemical composition analysis reveals that Al primarily partitions to B2 phase, suggesting Al is a stabilizer of B2 structure. With increasing Al content, more Ni and Al partition to the B2 phase due to the very negative mixing enthalpy of Ni and Al, and another phase enriched in Cr and Fe transforms from fcc to disordered bcc. Nano indentation measurements show that the hardness of AlxCoCrFeNi high-entropy alloy increases with Al content, accompanied by the decrease of ductility. The stability of single-phase solid solution in AlxCoCrFeNi HEAs is deduced from various criteria. Combined with the experiment results of other similar HEA systems, such as AlxCoCrFeNiCu, the effects of Al addition on the microstructure of AlxCoCrFeNi HEAs are discussed based on the Gibbs free energy of all competing phases and the fundamental properties of constituent elements. The aim of current study is to provide experimental evidence to establish a correlation between the microstructure and mechanical properties to search for high-entropy alloys with higher performances. (C) 2015 Elsevier B.V. All rights reserved.
引用
收藏
页码:15 / 22
页数:8
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