A dislocation-based yield strength model for nano-indentation size effect

Tao, Pengcheng; Ye, Fei; Gong, Jianming; Barrett, Richard A.; Leen, Seán B.

doi:10.1177/1464420721992796

Cited by 5 publications

(4 citation statements)

References 29 publications

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“…The surface hardness is, indeed, effective in determining a reduction of COF. Such a hardness increase is due to the plastic deformation caused by the microindentations which produce dislocations in the material's microstructure [31,32]. By increasing the hardness of the surface, the adhesion and plastic deformation between the surfaces was reduced, thus leading, in turn, to a better wear resistance of the surface.…”

Section: Discussion and Comparisonsmentioning

confidence: 99%

Tribological behavior of micro-indented 100Cr6 steel surfaces in dry contact conditions

guglielmi,

Davoodi,

Palumbo

et al. 2024

Preprint

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The aim of the present work is to investigate the tribological behaviour in dry conditions of a 100Cr6 steel, whose surface was textured using microindentation techniques. Specifically, dimples were created on the surface of a sphere using an automatic Microhardness tester equipped with a Vickers indenter, setting a load of 0.5N. Friction tests were performed at different speeds considering surfaces with two different Void Ratios (VRs). Both textured and untextured spherical surfaces were tested using a ball-on-disc tribometer. In addition, the effect of dimple size was evaluated by producing Vickers indented surfaces at a load of 5N per each indentation, while keeping the VR values unchanged and testing the frictional properties of such surfaces at a fixed speed of 4.18 mm/s. Textured surfaces were also characterized, before and after the tribological tests, in terms of surface microgeometry and nanohardness, using a light microscope, a scanning electron microscope, an atomic force microscope, a contact profilometer and a nano-indenter. Notably, compared to the untextured samples, the microindented samples exhibited a much lower Coefficient of Friction (COF), with a friction reduction compared to the untextured case ranging from 45–65%, depending on the VR values. We noted that the adoption of large dimples allows the reduction of the COF, already at smaller VR value but, in such a case, the presence of bulges at the edge of the dimple worsens the wear resistance of the counter-surface. The local measurement of strength by nanoindentations allowed to clarify that the friction reduction is determined by the work hardening effect produced by the microindentation texturing. The proposed approach can be applied using specific tools to effectively and selectively affect the friction behaviour of components, during its use or its production (for example in stamping operations).

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Section: Discussion and Comparisonsmentioning

confidence: 99%

Tribological behavior of micro-indented 100Cr6 steel surfaces in dry contact conditions

guglielmi,

Davoodi,

Palumbo

et al. 2024

Preprint

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“…The eventual micro-crack which can be created under the machining of the notch can also influence the orientation of the crack path. Referring to the research work of Tao et al 36 where a dislocation-based model was employed for dual phase material, an extension of the present developed model by involving microstrain and dislocation density in the constitutive equations, can be proposed to rectify the difference between experimental and numerical findings.…”

Section: Microstructural Analysismentioning

confidence: 98%

Variational approach and experimental investigation of the phase-field model predicting brittle fracture

Fraj

Hentati

Messaoudi

et al. 2023

Proceedings of the Institution of Mechanical Engineers, Part L:

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Cracks are described as sharp and diffusive surfaces in failure mechanical models. In this paper, a finite element model is developed by using a diffusive description of crack discontinuities. The main objective of this study is to prove the accuracy of the phase-field model in which the alternate minimization iteration and the spectral decomposition formulation are considered. We conduct a set of benchmark numerical tests on notched specimens using the phase-field model, which allows the prediction of the quasi-brittle failure. The fracture surface is approximated by a diffusive field, which interpolates between undamaged and fully damaged states. A mechanical loading was applied on quenched C90 steel and different obtained crack patterns are discussed. Microstructural analyses are performed to prove the accuracy of the proposed numerical approach. Through the determination of microstructural properties of untreated and quenched C90 steel, it is concluded that the presence of the micro-cracks may have a great influence on the crack path evolution.

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“…In order to study the influence of temperature on the damage and expansion process of nanoindentation single crystal silicon carbide, the initial temperature of the system was set to 0 K, 300 K, 600 K, 900 K; the low-temperature, room temperature, medium-high temperature and high-temperature environments were mapped, respectively. In order to maintain the temperature stability of the thermosphere atoms, adjust the velocity of the thermosphere atoms every 100 steps and, in order to eliminate the “size effect” [ 16 ] and “surface effect” in the nanoscale [ 17 ], set the X and Z directions of the simulation box as periodic boundaries and the Y direction as free boundaries to ensure that the calculation results are accurate. The calculation parameters simulated in this paper are shown in Table 1 .…”

Section: Model Buildingmentioning

confidence: 99%

Molecular Dynamics Simulation Analysis of Damage and Expansion Process of Nanoindentation Single-Crystal 3C-SiC Carbide Specimens at Different Temperature

Ning

Zhong

et al. 2023

Nanomaterials

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The molecular dynamics method was used to analyze the influence of simulated temperature on the damage expansion process of the 3C-SiC sample under nano-indentation loading in order to study the influence of temperature on the internal damage and expansion mechanism of the 3C-SiC single crystal sample further during the nano-indentation loading process. A simulation test platform for diamond indenter indentation was established. The process of stress and strain distribution, dislocation evolution, dislocation expansion and potential energy change were analyzed, combined with the radial distribution function and load displacement curve. The influence of temperature on the 3C-SiC material was discussed. The variation trend of the potential energy-step curve is basically the same at the temperatures of 0 K, 300 K, 600 K and 900 K. The difference in strain distribution was characterized by the influence of temperature on stress intensity, expansion direction and type. The microcosmic manifestation is the significant difference in the dislocation slip at low temperature. In the process of dislocation evolution and expansion, dislocation climbs at room temperature and increases at high temperature, which is closely related to energy release. This study has certain guiding significance for investigating the internal damage difference and temperature effect of the 3C-SiC sample.

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A dislocation-based yield strength model for nano-indentation size effect

Cited by 5 publications

References 29 publications

Tribological behavior of micro-indented 100Cr6 steel surfaces in dry contact conditions

Tribological behavior of micro-indented 100Cr6 steel surfaces in dry contact conditions

Variational approach and experimental investigation of the phase-field model predicting brittle fracture

Molecular Dynamics Simulation Analysis of Damage and Expansion Process of Nanoindentation Single-Crystal 3C-SiC Carbide Specimens at Different Temperature

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