物理学报2018，Vol.67Issue(5)：23-30,8.DOI:10.7498/aps.67.20171670
原子模拟钛中微孔洞的结构及其失效行为
Atomistic simulation of microvoid formation and its influence on crack nucleation in hexagonal titanium
摘要
Abstract
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.关键词
原子模拟/力学性能/空位团簇/裂纹Key words
atomistic simulation/mechanical behavior/vacancy cluster/crack引用本文复制引用
何燕,周刚,刘艳侠,王皞,徐东生,杨锐..原子模拟钛中微孔洞的结构及其失效行为[J].物理学报,2018,67(5):23-30,8.基金项目
国家重点基础研究发展计划(批准号:2016YFB0701304)、国家自然科学基金(批准号:51671195, 11674233, 61603265)和沈阳师范大学科技项目(批准号:L201521) 资助的课题.Project supported by the State Key Development Program for Basic Research of China (Grant No. 2016YFB0701304), the National Natural Science Foundation of China (Grant Nos. 51671195, 11674233, 61603265), and the Technology Foundation of Shenyang Normal University, China (Grant No. L201521). （批准号:2016YFB0701304）
