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

IMR OpenIR

	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.
	2018-03-05
发表期刊	ACTA PHYSICA SINICA
ISSN	1000-3290
卷号	67 期号:5 页码:-
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.
部门归属	[he yan ; zhou gang ; wang hao ; xu dong-sheng ; yang rui] chinese acad sci, inst met res, shenyang 110016, liaoning, peoples r china ; [he yan] univ chinese acad sci, beijing 100864, peoples r china ; [he yan] shenyang normal univ, coll phys sci & technol, shenyang 110034, liaoning, peoples r china ; [zhou gang] dalian univ technol, sch mat sci & engn, dalian 116024, peoples r china ; [liu yan-xia] liaoning univ, sch phys, shenyang 110036, liaoning, peoples r china
关键词	Stacking-fault Tetrahedra Dislocation Dipoles Dwell Fatigue Al Transformation Annihilation Aluminum Alloys Growth
学科领域	Physics, Multidisciplinary
资助者	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]
收录类别	SCI
语种	英语
WOS记录号	WOS:000428113900003
引用统计
文献类型	期刊论文
条目标识符	http://ir.imr.ac.cn/handle/321006/79437
专题	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):-.