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木虫 (著名写手)

Amorphous Solids

应助: 12 (小学生)
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虫号: 681623
注册: 2008-12-25
性别: GG
专业: 固体力学

[交流] 【资源】国际塑性上一篇最近金属玻璃的屈服和塑性的文章

Yielding and intrinsic plasticity of Ti–Zr–Ni–Cu–Be bulk metallic glass

J. Fornella, A. Concustella, S. Suriñacha, W.H. Lib, N. Cuadradoc, A. Gebertd, M.D. Baróa and J. Sorte, ,

aDepartament de Física, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain

bSchool of Materials Science and Engineering, Anhui University of Technology, 243002 Maanshan Anhui, China

cÀrea Tecnologia de Materials, Centre Tecnològic de Manresa, 08242 Manresa, Spain

dIFW Dresden, Institute for Metallic Materials, P.O. Box 27 00 16, D-01171, Dresden, Germany

eInstitució Catalana de Recerca i Estudis Avançats, Departament de Física, Universitat Autònoma de Barcelona, Faculty of Sciences, Building Cc, 08193 Bellaterra, Spain

Received 31 May 2008; revised 4 November 2008. Available online 24 November 2008.

Abstract
Bulk metallic glass with composition Ti40Zr25Ni8Cu9Be18 exhibits considerably high compressive yield stress, significant plasticity (with a concomitant vein-like fracture morphology) and relatively low density. Yielding and intrinsic plasticity of this alloy are discussed in terms of its thermal and elastic properties. An influence of normal stresses acting on the shear plane is evidenced by: (i) the fracture angle (<45°) and (ii) finite-element simulations of nanoindentation curves, which require the use of a specific yield criterion, sensitive to local normal stresses acting on the shear plane, to properly match the experimental data. The ratio between hardness and compressive yield strength (constraint factor) is analyzed in terms of several models and is best adjusted using a modified expanding cavity model incorporating a pressure-sensitivity index defined by the Drucker–Prager yield criterion. Furthermore, comparative results from compression tests and nanoindentation reveal that deformation also causes strain softening, a phenomenon which is accompanied with the occurrence of serrated plastic flow and results in a so-called indentation size effect (ISE). A new approach to model the ISE of this metallic glass using the free volume concept is presented.

Keywords: A. Yield condition; B. Elastic–plastic material; B. Metallic glass material; C. Mechanical testing; C. Nanoindentation

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转自：http://www.sciencenet.cn/bbs/showpost.aspx?id=49073

[ Last edited by hslining on 2009-9-12 at 09:12 ]

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