Phonon instability of a multi-principal element alloy

doi:10.1103/PhysRevB.107.184116

CORC > 力学研究所 > 中国科学院力学研究所 > 非线性力学国家重点实验室

	Phonon instability of a multi-principal element alloy
	Wang XS(王晓实); Wang YJ(王云江)
刊名	PHYSICAL REVIEW B
	2023-05-30
卷号	107 期号:18 页码:184116
ISSN号	2469-9950
DOI	10.1103/PhysRevB.107.184116
英文摘要	It is a common wisdom that the emergence of plasticity in crystalline solids is accompanied by the collapse of the softest vibrational mode. However, the recent advance in the multi-principal element alloys (MPEAs) complicates this scenario with essential local chemical inhomogeneity rendered by formation of the chemical short-range order (CSRO) via strong enthalpic interaction between specific atom pairs. Here we develop a set of computational metrics to characterize the features of phonons and the instability pathway in a prototypical ternary CoCrNi MPEA by atomistic simulations. There exists strong anharmonicity in MPEA quantified by a large Gruneisen parameter, which is modulated by the degree of CSRO. Both localized and extended vibrational modes exist at either low-or high-frequency vibrations, whereas extremely high-frequency modes prefer local vibration. Introduction of CSRO increases the phonon density of states at high frequency and reduces the degree of anharmonicity. Therefore, CSRO enhances elastic stability. Upon loading, phonon instability occurs via annihilation of the softest mode, akin to the scenario seen in conventional crystals. However, softening of several low-frequency modes occurs simultaneously in MPEA, and it is the cooperative softening of them that leads to the onset of plasticity. Amid phonon instability, essential variations in the Grueisen parameter and participation ratio are observed, signifying the correlation between vibrational and configurational space in such compositional complex alloys. The results of unusual phonon features could give insight into how the structure, elasticity, and plasticity interact in generic multi-component high-entropy alloys.
分类号	二类
WOS研究方向	Materials Science ; Physics
语种	英语
WOS记录号	WOS:001006505000001
资助机构	National Nat- ural Science Foundation of China [12072344] ; Youth Innovation Promotion Association of the Chinese Academy of Sciences
其他责任者	Wang, YJ (corresponding author), Chinese Acad Sci, Inst Mech, State Key Lab Nonlinear Mech, Beijing 100190, Peoples R China.
内容类型	期刊论文
源URL	[http://dspace.imech.ac.cn/handle/311007/92613]
专题	力学研究所_非线性力学国家重点实验室
作者单位	{Wang, Yun-Jiang} Chinese Acad Sci, Inst Mech, State Key Lab Nonlinear Mech, Beijing 100190, Peoples R China, Univ Chinese Acad Sci, Sch Engn Sci, Beijing 100049, Peoples R China
推荐引用方式 GB/T 7714	Wang XS,Wang YJ. Phonon instability of a multi-principal element alloy[J]. PHYSICAL REVIEW B,2023,107(18):184116.
APA	王晓实,&王云江.(2023).Phonon instability of a multi-principal element alloy.PHYSICAL REVIEW B,107(18),184116.
MLA	王晓实,et al."Phonon instability of a multi-principal element alloy".PHYSICAL REVIEW B 107.18(2023):184116.