Varying tensile fracture mechanisms of Cu and Cu-Zn alloys with reduced grain size: From necking to shearing instability

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	Varying tensile fracture mechanisms of Cu and Cu-Zn alloys with reduced grain size: From necking to shearing instability
	P. Zhang; S. Qu; M. X. Yang; G. Yang; S. D. Wu; S. X. Li; Z. F. Zhang
	2014
发表期刊	Materials Science and Engineering a-Structural Materials Properties Microstructure and Processing
ISSN	0921-5093
卷号	594 页码:309-320
摘要	In ultrafine-grained (UFG) or nanocrystalline (NC) materials, achieving high strength often induces loss of ductility due to the formation of shear fracture without obvious necking feature. To investigate mechanical properties and fracture mechanism with reduced grain size, the macroscopic tensile fracture behaviors of UFG or NC Cu and Cu-Zn alloys were systematically investigated. It is found that the tensile strength and uniform elongation of UFG or NC Cu and Cu-Zn alloys display simultaneously increasing trend. The limitation of ductility can be attributed to the occurrence of shear bands in these materials; their main characteristic, the shear fracture angle, decreases with decreasing grain size as well as the degree of necking. The macroscopic fracture mechanisms are explained using an Ellipse criterion in terms of modification of the stress state in the fracture zone. It is suggested that the reduction of necking degree results from the geometrical hardening effect due to the change of the stress state. As the degree of necking decreases with decreasing grain size, the tensile shear fracture angle decreases too in the UFG/NC materials. Thus improving the geometrical hardening ability may effectively inhibit the formation of shear fracture, as the nucleation of shear bands becomes difficult. (C) 2013 Elsevier B.V. All rights reserved.
部门归属	[zhang, p. ; qu, s. ; wu, s. d. ; li, s. x. ; zhang, z. f.] chinese acad sci, inst met res, shenyang natl lab mat sci, shenyang 110016, peoples r china. [yang, m. x. ; yang, g.] cent iron & steel res inst, beijing 100081, peoples r china. ; zhang, zf (reprint author), chinese acad sci, inst met res, shenyang natl lab mat sci, shenyang 110016, peoples r china. ; zhfzhang@imr.ac.cn
关键词	Cu-zn Alloy Equal-channel Angular Pressing (Ecap) Strength Fracture Mechanism Necking Shear Fracture Stacking-fault Energy High-pressure Torsion Severe Plastic-deformation Al Alloys Microstructural Evolution Nanocrystalline Materials Single-crystal Ductility Strength Orientation
URL	查看原文
语种	英语
文献类型	期刊论文
条目标识符	http://ir.imr.ac.cn/handle/321006/72601
专题	中国科学院金属研究所
推荐引用方式 GB/T 7714	P. Zhang,S. Qu,M. X. Yang,et al. Varying tensile fracture mechanisms of Cu and Cu-Zn alloys with reduced grain size: From necking to shearing instability[J]. Materials Science and Engineering a-Structural Materials Properties Microstructure and Processing,2014,594:309-320.
APA	P. Zhang.,S. Qu.,M. X. Yang.,G. Yang.,S. D. Wu.,...&Z. F. Zhang.(2014).Varying tensile fracture mechanisms of Cu and Cu-Zn alloys with reduced grain size: From necking to shearing instability.Materials Science and Engineering a-Structural Materials Properties Microstructure and Processing,594,309-320.
MLA	P. Zhang,et al."Varying tensile fracture mechanisms of Cu and Cu-Zn alloys with reduced grain size: From necking to shearing instability".Materials Science and Engineering a-Structural Materials Properties Microstructure and Processing 594(2014):309-320.