Atomistic simulation of microvoid formation and its influence on crack nucleation in hexagonal titanium

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	Atomistic simulation of microvoid formation and its influence on crack nucleation in hexagonal titanium
	He, Y; Zhou, G; Liu, YX; Wang, H; Xu, DS; Yang, R; Wang, H (reprint author), Chinese Acad Sci, Inst Met Res, Shenyang 110016, Liaoning, Peoples R China.
刊名	ACTA PHYSICA SINICA
	2018-03-05
卷号	67 期号:5 页码:-
关键词	Stacking-fault Tetrahedra Dislocation Dipoles Dwell Fatigue Al Transformation Annihilation Aluminum Alloys Growth
ISSN号	1000-3290
英文摘要	During the plastic deformation of hexagonal metals, it is easy to generate the point defect clusters with complex shapes and configurations due to their anisotropic properties. The interactions among these clusters and between these clusters and moving dislocations significantly influence the physical and mechanical properties of hexagonal materials. However, none of these issues in particular concerning the evolutions of vacancy clusters, the formation of microvoids, and the crack nucleation and propagation, is comprehensively understood on an atomic scale. In the present work, we first employ the activation-relaxation technique, in combination with ab initio and interatomic potential calculations, to systematically investigate vacancy cluster configurations in titanium and the transformation between these clusters. The results indicate the stable and metastable configurations of vacancy clusters at various sizes and activation energies of their dissociation, combination and migration. It is found that the formation and migration energies decrease with the size of vacancy cluster increasing. Small vacancy clusters stabilize at configurations with special symmetry, while large clusters transform into microvoids or microcracks. High-throughput molecular dynamics simulations are subsequently employed to investigate the influences of these clusters on plastic deformation under tensile loading. The clusters are found to facilitate the crack nucleation by providing lower critical stress, which decreases with the size of the vacancy clusters increasing. Under tensile loading, cracks are first nucleated at small clusters and then grow up, while large clusters form microvoids and cracks directly grow up.; During the plastic deformation of hexagonal metals, it is easy to generate the point defect clusters with complex shapes and configurations due to their anisotropic properties. The interactions among these clusters and between these clusters and moving dislocations significantly influence the physical and mechanical properties of hexagonal materials. However, none of these issues in particular concerning the evolutions of vacancy clusters, the formation of microvoids, and the crack nucleation and propagation, is comprehensively understood on an atomic scale. In the present work, we first employ the activation-relaxation technique, in combination with ab initio and interatomic potential calculations, to systematically investigate vacancy cluster configurations in titanium and the transformation between these clusters. The results indicate the stable and metastable configurations of vacancy clusters at various sizes and activation energies of their dissociation, combination and migration. It is found that the formation and migration energies decrease with the size of vacancy cluster increasing. Small vacancy clusters stabilize at configurations with special symmetry, while large clusters transform into microvoids or microcracks. High-throughput molecular dynamics simulations are subsequently employed to investigate the influences of these clusters on plastic deformation under tensile loading. The clusters are found to facilitate the crack nucleation by providing lower critical stress, which decreases with the size of the vacancy clusters increasing. Under tensile loading, cracks are first nucleated at small clusters and then grow up, while large clusters form microvoids and cracks directly grow up.
学科主题	Physics, Multidisciplinary
语种	英语
资助机构	State Key Development Program for Basic Research of China [2016YFB0701304]; National Natural Science Foundation of China [51671195, 11674233, 61603265]; Technology Foundation of Shenyang Normal University, China [L201521]
公开日期	2018-06-05
内容类型	期刊论文
源URL	[http://ir.imr.ac.cn/handle/321006/79437]
专题	金属研究所_中国科学院金属研究所
通讯作者	Wang, H (reprint author), Chinese Acad Sci, Inst Met Res, Shenyang 110016, Liaoning, Peoples R China.
推荐引用方式 GB/T 7714	He, Y,Zhou, G,Liu, YX,et al. Atomistic simulation of microvoid formation and its influence on crack nucleation in hexagonal titanium[J]. ACTA PHYSICA SINICA,2018,67(5):-.
APA	He, Y.,Zhou, G.,Liu, YX.,Wang, H.,Xu, DS.,...&Wang, H .(2018).Atomistic simulation of microvoid formation and its influence on crack nucleation in hexagonal titanium.ACTA PHYSICA SINICA,67(5),-.
MLA	He, Y,et al."Atomistic simulation of microvoid formation and its influence on crack nucleation in hexagonal titanium".ACTA PHYSICA SINICA 67.5(2018):-.