Theoretical study on crystal structures, elastic stiffness, and intrinsic thermal conductivities of beta-, gamma-, and delta-Y2Si2O7

IMR OpenIR

	Theoretical study on crystal structures, elastic stiffness, and intrinsic thermal conductivities of beta-, gamma-, and delta-Y2Si2O7
	Y. X.; Wang Luo, J. M.; Li, J. N.; Hu, Z. J.; Wang, J. Y.
	2015
发表期刊	Journal of Materials Research
ISSN	0884-2914
卷号	30 期号:4 页码:493-502
摘要	Yttrium disilicates (Y2Si2O7), well known for its complex polymorphism, are promising candidates for high-temperature structural materials and environmental barrier coatings due to their good properties in harsh environments. In this study, the crystal structure, elastic stiffness, and temperature dependence of the lattice thermal conductivity of beta-, gamma-, and delta-Y2Si2O7 are studied using first-principles calculations. Divergences of elastic stiffness are attributed to the different crystal structures and bonding strength of the polymorphs. Specially, the Si-O-Si bridge of delta phase bends with an angle of 158.1 degrees, and this configuration enhances the bonding heterogeneity but weakens the bonding strength and stability. According to the prediction of lattice thermal conductivity using the Debye-Slack model, beta-, gamma-, and delta-Y2Si2O7 are characterized with very low thermal conductivity. In addition, the deviation of lattice thermal conductivities of Y2Si2O7 polymorphs is dominated by two vital factors, anharmonicity of phonon scattering and complexity of crystal structure. The present method could be used to investigate the specific factors dominating lattice thermal conductivity and may promisingly be generalized to search novel candidates with extremely low lattice thermal conductivity.
部门归属	[luo, yixiu ; wang, jiemin ; wang, jingyang] chinese acad sci, shenyang natl lab mat sci, inst met res, high performance ceram div, shenyang 110016, peoples r china. [li, junning ; hu, zijun] aerosp res inst mat & proc technol, sci & technol adv funct composite lab, beijing 100076, peoples r china. ; wang, jy (reprint author), chinese acad sci, shenyang natl lab mat sci, inst met res, high performance ceram div, shenyang 110016, peoples r china. ; jywang@imr.ac.cn
关键词	X-ray-diffraction Mechanical-properties Yttrium Silicates Barrier Coatings Gamma-y2si2o7 Disilicate Powder Composites Stability Behavior
URL	查看原文
文献类型	期刊论文
条目标识符	http://ir.imr.ac.cn/handle/321006/73881
专题	中国科学院金属研究所
推荐引用方式 GB/T 7714	Y. X.,Wang Luo, J. M.,Li, J. N.,et al. Theoretical study on crystal structures, elastic stiffness, and intrinsic thermal conductivities of beta-, gamma-, and delta-Y2Si2O7[J]. Journal of Materials Research,2015,30(4):493-502.
APA	Y. X.,Wang Luo, J. M.,Li, J. N.,Hu, Z. J.,&Wang, J. Y..(2015).Theoretical study on crystal structures, elastic stiffness, and intrinsic thermal conductivities of beta-, gamma-, and delta-Y2Si2O7.Journal of Materials Research,30(4),493-502.
MLA	Y. X.,et al."Theoretical study on crystal structures, elastic stiffness, and intrinsic thermal conductivities of beta-, gamma-, and delta-Y2Si2O7".Journal of Materials Research 30.4(2015):493-502.