Brittle/Ductile Transition Phenomena Observed in Computer Simulations of Machining Defect-Free Monocrystalline Silicon

The physical model of fixed-abrasive diamond wire-sawing monocrystalline silicon was founded to analyze the elastic deformation of the wire, supposing that every grit was connected to the surface of the wire by a spring. Ignoring lateral vibration of the wire, the geometrical model of wire-sawing was founded; the average cut depth of single grit was calculated theoretically. Based the indentation fracture mechanics and investigations on brittle-ductile transition of machining monocrystalline silicon, the removal mechanism and surface formation was studied theoretically. It shows that in the case of wire-sawing velocity of 10m/s or higher, infeed velocity of 0.20mm/s and diamond grain size of 64μm or smaller, the chip formation and material removal is in a brittle regime mainly, but the silicon wafer surface formation is sawed in a ductile regime. The size of the abrasives, the wire-saw velocity and infeed velocity can influence the sawing process obviously.

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Brittle-Ductile Transition in Nano Bending of Monocrystalline Silicon Carbide Analyzed by Molecular Dynamics Simulation

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.257-258.15 ◽

2004 ◽

Vol 257-258 ◽

pp. 15-20 ◽

Cited By ~ 3

Author(s):

Hiroaki Tanaka ◽

M. Sano ◽

Shiro Shimada

Keyword(s):

Molecular Dynamics ◽

Silicon Carbide ◽

Molecular Dynamics Simulation ◽

Monocrystalline Silicon ◽

Dynamics Simulation ◽

Brittle Ductile Transition

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A study on the surface quality and brittle–ductile transition during the elliptical vibration-assisted nanocutting process on monocrystalline silicon via molecular dynamic simulations

RSC Advances ◽

10.1039/c6ra25426h ◽

2017 ◽

Vol 7 (7) ◽

pp. 4179-4189 ◽

Cited By ~ 19

Author(s):

Bo Zhu ◽

Dan Zhao ◽

Hongwei Zhao ◽

Jian Guan ◽

Pengliang Hou ◽

...

Keyword(s):

Molecular Dynamic ◽

Surface Quality ◽

Md Simulation ◽

Diamond Tool ◽

Monocrystalline Silicon ◽

Molecular Dynamic Simulations ◽

Dynamic Simulations ◽

Elliptical Vibration ◽

Brittle Ductile Transition

Molecular dynamic (MD) simulation was applied to investigate surface quality and brittle–ductile transition of monocrystalline silicon with a diamond tool during elliptical vibration-assisted nanocutting (EVANC) and traditional nanocutting process.

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Brittle-ductile transition in monocrystalline silicon analysed by molecular dynamics simulation

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1243/095440604774202213 ◽

2004 ◽

Vol 218 (6) ◽

pp. 583-590 ◽

Cited By ~ 23

Author(s):

H Tanaka ◽

S Shimada ◽

N Ikawa

Keyword(s):

Molecular Dynamics ◽

Plastic Deformation ◽

Phase Transformation ◽

Stress Field ◽

Crack Initiation ◽

Material Removal ◽

Monocrystalline Silicon ◽

Dynamics Simulation ◽

Depth Of Cut ◽

Brittle Ductile Transition

For a better understanding of essential mechanisms of material removal at extremely small depth of cut and of the brittle-ductile transition in the material removal process of monocrystalline silicon, nonometric deformation behaviour in three-point bending of defect-free monocrystalline silicon is analysed by molecular dynamics (MD) computer simulation. MD simulations show that plastic deformation takes place through a phase transformation from diamond to amorphous structures. The critical octahedral shearing stress for phase transformation is estimated to be 12–14 GPa. In the deformed region, a crack nucleus on atomic scale can be generated owing to thermally activated vibration of atoms. After the crack nucleus, the crack extension takes place under a certain stress field. The crack initition takes place when a tensile stress reaches a certain critical value of about 30 GPa at the crack nucleus. The critical values for plastic deformation and crack initiation depend on crystal orientation and hydrostatic pressure. It is shown that there can also be critical criteria of the stress field to determine whether plastic deformation or crack initiation would predomiantly take place. When the plastic deformation proceeds to a crack initiation, ductile mode machining can be realized.

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Brittle-Ductile Transition in Fiber-Reinforced Composites

International Journal of Modern Physics C ◽

10.1142/s0129183198000789 ◽

1998 ◽

Vol 09 (06) ◽

pp. 851-856 ◽

Cited By ~ 5

Author(s):

Ismael L. Menezes-Sobrinho ◽

José-Guilherme Moreira ◽

Américo T. Bernardes

Keyword(s):

Stochastic Model ◽

Computer Simulations ◽

Industrial Applications ◽

Fiber Reinforced Composites ◽

Reinforced Composites ◽

Fiber Reinforced ◽

Microscopic Mechanism ◽

Self Organized ◽

Brittle Ductile Transition ◽

Self Organized Criticality

Fiber-reinforced composites are a class of material with increasing industrial applications. Computer simulations have been used in order to understand the microscopic mechanism which can explain their mechanical behavior and several models have been introduced in the last decade. In this paper we introduce a criterion to define the brittle-ductile transition region in unidirectional fiber-reinforced composites. In order to simulate a fiber bundle, a recently introduced stochastic model is used. The results obtained with our criterion are compared with those obtained by using a self-organized criticality (SOC) approach.

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A High Resolution Study of G.P. Zones in Aluminum - 4.2 at % Silver

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100055904 ◽

1982 ◽

Vol 40 ◽

pp. 722-723 ◽

Cited By ~ 1

Author(s):

R. Gronsky

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

High Resolution ◽

Computer Simulations ◽

Structural Characteristics ◽

X Ray Diffraction ◽

X Ray ◽

Transmission Electron ◽

Resolution Study

The phenomenon of clustering in Al-Ag alloys has been extensively studied since the early work of Guinierl, wherein the pre-precipitation state was characterized as an assembly of spherical, ordered, silver-rich G.P. zones. Subsequent x-ray and TEM investigations yielded results in general agreement with this model. However, serious discrepancies were later revealed by the detailed x-ray diffraction - based computer simulations of Gragg and Cohen, i.e., the silver-rich clusters were instead octahedral in shape and fully disordered, atleast below 170°C. The object of the present investigation is to examine directly the structural characteristics of G.P. zones in Al-Ag by high resolution transmission electron microscopy.

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Multislice calculations for quasi-periodic and non-periodic objects

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100173820 ◽

1990 ◽

Vol 48 (4) ◽

pp. 138-139

Author(s):

R. Herrera ◽

A. Gómez

Keyword(s):

Electron Diffraction ◽

Computer Simulations ◽

Periodic Table ◽

Amorphous Materials ◽

Space Group ◽

Essential Step ◽

Shape Effects ◽

Atomic Scattering ◽

Diffraction Patterns ◽

Periodic Continuation

Computer simulations of electron diffraction patterns and images are an essential step in the process of structure and/or defect elucidation. So far most programs are designed to deal specifically with crystals, requiring frequently the space group as imput parameter. In such programs the deviations from perfect periodicity are dealt with by means of “periodic continuation”.However, for many applications involving amorphous materials, quasiperiodic materials or simply crystals with defects (including finite shape effects) it is convenient to have an algorithm capable of handling non-periodicity. Our program “HeGo” is an implementation of the well known multislice equations in which no periodicity assumption is made whatsoever. The salient features of our implementation are: 1) We made Gaussian fits to the atomic scattering factors for electrons covering the whole periodic table and the ranges [0-2]Å−1 and [2-6]Å−1.

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Computer simulations for the TEM bend contour technique

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100163137 ◽

1996 ◽

Vol 54 ◽

pp. 134-135

Author(s):

Vladimir Yu. Kolosov ◽

Anders R. Thölén

Keyword(s):

Computer Simulations ◽

Real Space ◽

Advantages And Disadvantages ◽

Short Overview ◽

Diffraction Contrast ◽

Beam Method ◽

Convergent Beam ◽

Contour Technique

In this paper we give a short overview of two TEM applications utilizing the extinction bend contour technique (BC) giving the advantages and disadvantages; especially we consider two areas in which the BC technique remains unique. Special attention is given to an approach including computer simulations of TEM micrographs.BC patterns are often observed in TEM studies but are rarely exploited in a serious way. However, this type of diffraction contrast was one of the first to be used for analysis of imperfections in crystalline foils, but since then only some groups have utilized the BC technique. The most extensive studies were performed by Steeds, Eades and colleagues. They were the first to demonstrate the unique possibilities of the BC method and named it real space crystallography, which developed later into the somewhat similar but more powerful convergent beam method. Maybe, due to the difficulties in analysis, BCs have seldom been used in TEM, and then mainly to visualize different imperfections and transformations.

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