Unprecedented plastic flow channel in gamma-B-28 through ultrasoft bonds: A challenge to superhardness

doi:10.1103/PhysRevMaterials.2.123602

CORC > 金属研究所 > 中国科学院金属研究所

	Unprecedented plastic flow channel in gamma-B-28 through ultrasoft bonds: A challenge to superhardness
	Zhang, SH ; Zheng, X ; Jin, QQ ; Zheng, SJ ; Legut, D ; Yu, XH ; Gou, HY ; Fu, ZH ; Guo, YQ ; Yan, BM
刊名	PHYSICAL REVIEW MATERIALS
	2018-12-13
卷号	2 期号:12 页码:-
ISSN号	2475-9953
DOI	10.1103/PhysRevMaterials.2.123602
英文摘要	A longstanding controversy remains whether gamma-B-28 is intrinsically superhard or not, i.e., H-upsilon >= 40 GPa. Here we perform comprehensive investigations on the mechanical properties of gamma-B-28 to reveal the plasticity and failure mode of gamma-B-28 through the unique combination of microindentation experiment, the ideal strength approach, and the ab initio informed Peierls-Nabarro model. A low load-invariant hardness of similar to 30 GPa is found for both polycrystalline and monocrystalline gamma-B-28. By carefully checking the strength anisotropy and strain facilitated phonon instability, a surprising ideal strength of 23.1 GPa is revealed along the (001)[010] slip system for gamma-B-28, together with an inferior Peierls stress of 3.2 GPa, both of which are close to those of B6O and ZrB12 yet much lower than those of diamond and c-BN. These results suggest that gamma-B-28 could not be intrinsically superhard. Atomistic simulation and electronic structure analysis uncover an unprecedented plastic flow channel through the specific ultrasoft bonding, which causes a dramatic softening of gamma-B-28. These findings highlight an approach to quantifying the realistic hardness by means of two plasticity descriptors beyond the elastic limit, i.e., the ideal strength approach and the Peierls-Nabarro model.
学科主题	Materials Science, Multidisciplinary
语种	英语
WOS记录号	WOS:000452971600001
内容类型	期刊论文
源URL	[http://ir.imr.ac.cn/handle/321006/79778]
专题	金属研究所_中国科学院金属研究所
作者单位	1.[Zhang, S. H. 2.Fu, Z. H. 3.Guo, Y. Q. 4.Zhang, R. F.] Beihang Univ, Sch Mat Sci & Engn, Beijing 100191, Peoples R China 5.[Zhang, S. H. 6.Fu, Z. H. 7.Guo, Y. Q. 8.Zhang, R. F.] Beihang Univ, Int Res Inst Multidisciplinary Sci, Ctr Integrated Computat Mat Engn, Beijing 100191, Peoples R China 9.[Zheng, X. 10.Yu, X. H.
推荐引用方式 GB/T 7714	Zhang, SH,Zheng, X,Jin, QQ,et al. Unprecedented plastic flow channel in gamma-B-28 through ultrasoft bonds: A challenge to superhardness[J]. PHYSICAL REVIEW MATERIALS,2018,2(12):-.
APA	Zhang, SH.,Zheng, X.,Jin, QQ.,Zheng, SJ.,Legut, D.,...&Zhang, RF.(2018).Unprecedented plastic flow channel in gamma-B-28 through ultrasoft bonds: A challenge to superhardness.PHYSICAL REVIEW MATERIALS,2(12),-.
MLA	Zhang, SH,et al."Unprecedented plastic flow channel in gamma-B-28 through ultrasoft bonds: A challenge to superhardness".PHYSICAL REVIEW MATERIALS 2.12(2018):-.