Deformation and rupture of crystals with covalent interatomic bonds

Trefilov, V. I.; Milman, Yu.V.; Grigoriev, O. N.

doi:10.1016/0146-3535(88)90019-6

Cited by 29 publications

(23 citation statements)

References 19 publications

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“…1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 Data for W are from this work. Other data are from: Si [2], GaAs [22], Ge [3], Al 2 O 3 [4], Mo [10,23], SiC [25], TiAl [7], diamond [26], Fe-3%Si [27], Fe [28], V [28]. The dashed line represents the best linear fit to the data, which gives E BDT / kT BDT = 25.…”

Section: Acknowledgmentsmentioning

confidence: 99%

Strain-rate dependence of the brittle-to-ductile transition temperature in tungsten

Giannattasio¹,

Roberts²

2007

Philosophical Magazine

163

110

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rate dependence of the brittle-to-ductile transition temperature in tungsten. Philosophical Magazine, Taylor & Francis, 2008, 87 (17) AbstractWe have investigated the strain rate dependence of the brittle-to-ductile transition (BDT) temperature in pre-cracked tungsten single-crystals and polycrystals. There is an unambiguousArrhenius relationship over four decades of strain rate, giving an activation energy for the process controlling the BDT of 1.05 eV. This is equal to the activation energy for double-kink formation on screw dislocations, suggesting that their motion controls the brittle-ductile transition.

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Section: Acknowledgmentsmentioning

confidence: 99%

Strain-rate dependence of the brittle-to-ductile transition temperature in tungsten

Giannattasio¹,

Roberts²

2007

Philosophical Magazine

163

110

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“…The authors concluded that within the temperature region below 200°C, the hardness values were determined by the fracture stress of SiC and thus remained constant and only above this threshold the measured hardness was related to the yielding of SiC. Other studies measuring the hardness with temperature of a-SiC found a higher threshold temperature of around 400°C [40][41][42].…”

Section: Variation In Grain Sizementioning

confidence: 98%

Comparison study of silicon carbide coatings produced at different deposition conditions with use of high temperature nanoindentation

et al. 2016

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The elastic modulus and hardness of different silicon carbide (SiC) coatings in tristructural-isotropic (TRISO) fuel particles were measured by in situ high temperature nanoindentation up to 500°C. Three samples fabricated by different research institutions were compared. Due to varied fabrication parameters the samples exhibited different grain sizes and one contained some visible porosity. However, irrespective of the microstructural features in each case the hardness was found to be very similar in the three coatings around 35 GPa at room temperature. Compared with the significantly coarser grained bulk CVD SiC, the drop in hardness with temperature was less pronounced for TRISO particles, suggesting that the presence of grain boundaries impeded plastic deformation. The elastic modulus differed for the three TRISO coatings with room temperature values ranging from 340 to 400 GPa. With increasing measurement temperature the elastic modulus showed a continuous decrease.

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“…Features of the diamond deformation during indentation by diamond indenter are considered in [10]. However, we can evaluate the quantity Y S /E S on the basis of the Meyer hardness of diamond at room temperature HM = 150 GPa [20] assuming that, as for high-hardness ceramics, for diamond, Y S ≈ HM. For diamond and for the value E = 1200 GPa, we obtain θ S Y S ≈ 0.23, i.e., the compressibility of the deformation core is particularly substantial for diamond and high-hardness ceramic materials.…”

Section: Theoretical Background Scheme and Equations Of The Improvedmentioning

confidence: 99%

Application of the Improved Inclusion Core Model of the Indentation Process for the Determination of Mechanical Properties of Materials

et al. 2017

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Abstract:The improved Johnson inclusion core model of indentation by conical and pyramidal indenters in which indenter is elastically deformed and a specimen is elastoplastically deformed under von Mises yield condition, was used for determination of mechanical properties of materials with different types of interatomic bond and different crystalline structures. This model enables us to determine approximately the Tabor parameter C = HM/Y S (where HM is the Meyer hardness and Y S is the yield stress of the specimen), size of the elastoplastic zone in the specimen, effective apex angle of the indenter under load, and effective angle of the indent after unloading. It was shown that the Tabor parameter and the size of elastoplastic deformation zone increase monotonically with the increase of the plasticity characteristic δ H , which is determined in indentation experiments using the early elaborated by the several authors of this article method. The corresponding analytical dependencies were obtained and their physical nature is discussed. For the materials studied in this work, the Tabor parameter ranges from 1 to 4. At the same time, for structural metallic alloys its value is between 2.8 and 3.1 in agreement with the results obtained by Tabor. A very simple technique developed in this article allows one to determine from the standard indentation test not only the hardness of a material but also its yield stress and plasticity. This makes the indentation test results significantly more informative.

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Deformation and rupture of crystals with covalent interatomic bonds

Cited by 29 publications

References 19 publications

Strain-rate dependence of the brittle-to-ductile transition temperature in tungsten

Strain-rate dependence of the brittle-to-ductile transition temperature in tungsten

Comparison study of silicon carbide coatings produced at different deposition conditions with use of high temperature nanoindentation

Application of the Improved Inclusion Core Model of the Indentation Process for the Determination of Mechanical Properties of Materials

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