Segregation and diffusion behaviours of helium at grain boundaries in silicon carbide ceramics: first-principles calculations and experimental investigations

doi:10.1016/j.jeurceramsoc.2022.04.014

	Segregation and diffusion behaviours of helium at grain boundaries in silicon carbide ceramics: first-principles calculations and experimental investigations
	Sun, Jingjing 1,6; You, Yu-Wei 5; Wu, Xuebang 4; Song, Hong-Yue 1,6; Li, B. S.3; Liu, C. S.4; Krsjak, Vladimir 2
刊名	JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
	2022-08-01
卷号	42
关键词	SiC ceramics Grain boundaries Helium segregation First-principles calculations Diffusion
ISSN号	0955-2219
DOI	10.1016/j.jeurceramsoc.2022.04.014
通讯作者	Sun, Jingjing(sj1993@mail.ustc.edu.cn) ; Li, B. S.(libingshengmvp@163.com)
英文摘要	Under a severe neutron irradiation environment, helium behaviour has become a significant concern due to helium-induced degradation of mechanical properties in SiC structural materials. Experimental observations showed that helium prefers to aggregate at grain boundaries (GBs) in SiC ceramics. However, the interaction mechanisms between helium and GBs have remained unclear. By performing first-principles calculations, we studied helium segregation at six symmetric tilt GBs and helium diffusion along and across the GBs. The solution energies of helium at the GBs are much lower than that of helium in grains, indicating preferential helium segregation at the GBs. The negative segregation energies of helium decrease linearly with the excess volume of GBs and the relative charge densities of the interstitial sites, which reveals that helium easily segregates at the GBs having open structures and low charge density interstitial sites. The interstitial helium atoms at GBs are difficult to form clusters due to weak interactions. The diffusion energy barriers of helium along the GBs sigma 9(221) [110] and sigma 27(552)[110] in the direction of tilt axis [110] are much lower than that of helium in the grains. The two GBs can significantly enhance the helium diffusivity, serving as fast diffusion channels for helium. The calculation results are analysed and compared with our experimental data.
资助项目	National Key Research and Devel-opment Program of China[2017YFE0302400] ; National Natural Science Foundation of China[12075194] ; National Natural Science Foundation of China[12005320] ; Science and Technology on Surface Physics and Chemistry Laboratory[02020517]
WOS关键词	ELASTIC BAND METHOD ; AB-INITIO ; BUBBLE FORMATION ; HYDROGEN ; ATOMS ; TEMPERATURE ; COMPOSITES ; CLUSTERS ; GAS
WOS研究方向	Materials Science
语种	英语
出版者	ELSEVIER SCI LTD
WOS记录号	WOS:000797696300003
资助机构	National Key Research and Devel-opment Program of China ; National Natural Science Foundation of China ; Science and Technology on Surface Physics and Chemistry Laboratory
内容类型	期刊论文
源URL	[http://ir.hfcas.ac.cn:8080/handle/334002/131029]
专题	中国科学院合肥物质科学研究院
通讯作者	Sun, Jingjing; Li, B. S.
作者单位	1.Zhongyuan Univ Technol, Zhengzhou Key Lab Lowdimens Quantum Mat & Devices, Zhengzhou 460007, Peoples R China 2.Slovak Univ Technol Bratislava, Inst Nucl & Phys Engn, Fac Elect Engn & Informat Technol, Ilkovicova 3, Bratislava 81219, Slovakia 3.Southwest Univ Sci & Technol, State Key Lab Environm Friendly Energy Mat, Mianyang 621010, Peoples R China 4.Chinese Acad Sci, Inst Solid State Phys, Key Lab Mat Phys, POB 1129, Hefei 230031, Peoples R China 5.Anhui Jianzhu Univ, Sch Math & Phys, Hefei 230601, Peoples R China 6.Zhongyuan Univ Technol, Coll Sci, Zhengzhou 450007, Peoples R China
推荐引用方式 GB/T 7714	Sun, Jingjing,You, Yu-Wei,Wu, Xuebang,et al. Segregation and diffusion behaviours of helium at grain boundaries in silicon carbide ceramics: first-principles calculations and experimental investigations[J]. JOURNAL OF THE EUROPEAN CERAMIC SOCIETY,2022,42.
APA	Sun, Jingjing.,You, Yu-Wei.,Wu, Xuebang.,Song, Hong-Yue.,Li, B. S..,...&Krsjak, Vladimir.(2022).Segregation and diffusion behaviours of helium at grain boundaries in silicon carbide ceramics: first-principles calculations and experimental investigations.JOURNAL OF THE EUROPEAN CERAMIC SOCIETY,42.
MLA	Sun, Jingjing,et al."Segregation and diffusion behaviours of helium at grain boundaries in silicon carbide ceramics: first-principles calculations and experimental investigations".JOURNAL OF THE EUROPEAN CERAMIC SOCIETY 42(2022).