The Experts below are selected from a list of 9171 Experts worldwide ranked by ideXlab platform
Alain Iost - One of the best experts on this subject based on the ideXlab platform.
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quantitative approach to determine the mechanical properties by Nanoindentation Test application on sandblasted materials
Tribology International, 2015Co-Authors: Y Xia, Maxence Bigerelle, Alain Iost, S Bouvier, Pierre-emmanuel MazeranAbstract:A novel method is developed to improve the accuracy in determining the mechanical properties from Nanoindentation curves. The key point of this method is the simultaneous statistical treatment of several loading curves to correct the zero point error and identify the material properties considering size effects. The method is applied to four sandblasted aluminum-based specimens with different surface roughness. A linear relationship is obtained between the standard deviation of the initial contact error and the roughness which highlights the effect of the surface roughness on the reproducibility of the indentation curves. Moreover, the smaller standard deviation of the hardness given by the method confirms the importance of considering the initial contact error for an accurate determination of the material properties.
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Effect of surface roughness in the determination of the mechanical properties of material using Nanoindentation Test
Scanning, 2014Co-Authors: Y Xia, Maxence Bigerelle, J. Marteau, P.-e. Mazeran, S. Bouvier, Alain IostAbstract:A quantitative model is proposed for the estimation of macro-hardness using Nanoindentation Tests. It decreases the effect of errors related to the non-reproducibility of the Nanoindentation Test on calculations of macro-hardness by taking into account the indentation size effect and the surface roughness. The most innovative feature of this model is the simultaneous statistical treatment of all the Nanoindentation loading curves. The curve treatment mainly corrects errors in the zero depth determination by correlating their positions through the use of a relative reference. First, the experimental loading curves are described using the Bernhardt law. The fitted curves are then shifted, in order to simultaneously reduce the gaps between them that result from the scatter in the experimental curves. A set of shift depths, Δhc, is therefore identified. The proposed approach is applied to a large set of TiAl6V4 titanium-based samples with different roughness levels, polished by eleven silicon carbide sandpapers from grit paper 80 to 4,000. The result reveals that the scatter degree of the indentation curves is higher when the surface is rougher. The standard deviation of the shift Δhc is linearly connected to the standard deviation of the surface roughness, if the roughness is high-pass filtered in the scale of the indenter (15 µm). Using the proposed method, the estimated macro-hardness for eleven studied TiAl6V4 samples is in the range of 3.5–4.1 GPa, with the smallest deviation around 0.01 GPa, which is more accurate than the one given by the Nanoindentation MTS™ system, which uses an average value (around 4.3 ± 0.5 GPa). Moreover, the calculated Young's modulus of the material is around 136 ± 20 GPa, which is similar to the modulus in literature.
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Effect of surface roughness in the determination of the mechanical properties of material using Nanoindentation Test
Scanning, 2013Co-Authors: Y Xia, Pierre-emmanuel Mazeran, Maxence Bigerelle, J. Marteau, S. Bouvier, Alain IostAbstract:Summary A quantitative model is proposed for the estimation of macro-hardness using Nanoindentation Tests. It decreases the effect of errors related to the non-reproducibility of the Nanoindentation Test on calculations of macro-hardness by taking into account the indentation size effect and the surface roughness. The most innovative feature of this model is the simultaneous statistical treatment of all the Nanoindentation loading curves. The curve treatment mainly corrects errors in the zero depth determination by correlating their positions through the use of a relative reference. First, the experimental loading curves are described using the Bernhardt law. The fitted curves are then shifted, in order to simultaneously reduce the gaps between them that result from the scatter in the experimental curves. A set of shift depths, Δhc, is therefore identified. The proposed approach is applied to a large set of TiAl6V4 titanium-based samples with different roughness levels, polished by eleven silicon carbide sandpapers from grit paper 80 to 4,000. The result reveals that the scatter degree of the indentation curves is higher when the surface is rougher. The standard deviation of the shift Δhc is linearly connected to the standard deviation of the surface roughness, if the roughness is high-pass filtered in the scale of the indenter (15 µm). Using the proposed method, the estimated macro-hardness for eleven studied TiAl6V4 samples is in the range of 3.5–4.1 GPa, with the smallest deviation around 0.01 GPa, which is more accurate than the one given by the Nanoindentation MTS™ system, which uses an average value (around 4.3 ± 0.5 GPa). Moreover, the calculated Young's modulus of the material is around 136 ± 20 GPa, which is similar to the modulus in literature. SCANNING 36:134–149, 2014. © 2013 Wiley Periodicals, Inc.
Y Xia - One of the best experts on this subject based on the ideXlab platform.
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quantitative approach to determine the mechanical properties by Nanoindentation Test application on sandblasted materials
Tribology International, 2015Co-Authors: Y Xia, Maxence Bigerelle, Alain Iost, S Bouvier, Pierre-emmanuel MazeranAbstract:A novel method is developed to improve the accuracy in determining the mechanical properties from Nanoindentation curves. The key point of this method is the simultaneous statistical treatment of several loading curves to correct the zero point error and identify the material properties considering size effects. The method is applied to four sandblasted aluminum-based specimens with different surface roughness. A linear relationship is obtained between the standard deviation of the initial contact error and the roughness which highlights the effect of the surface roughness on the reproducibility of the indentation curves. Moreover, the smaller standard deviation of the hardness given by the method confirms the importance of considering the initial contact error for an accurate determination of the material properties.
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Effect of surface roughness in the determination of the mechanical properties of material using Nanoindentation Test
Scanning, 2014Co-Authors: Y Xia, Maxence Bigerelle, J. Marteau, P.-e. Mazeran, S. Bouvier, Alain IostAbstract:A quantitative model is proposed for the estimation of macro-hardness using Nanoindentation Tests. It decreases the effect of errors related to the non-reproducibility of the Nanoindentation Test on calculations of macro-hardness by taking into account the indentation size effect and the surface roughness. The most innovative feature of this model is the simultaneous statistical treatment of all the Nanoindentation loading curves. The curve treatment mainly corrects errors in the zero depth determination by correlating their positions through the use of a relative reference. First, the experimental loading curves are described using the Bernhardt law. The fitted curves are then shifted, in order to simultaneously reduce the gaps between them that result from the scatter in the experimental curves. A set of shift depths, Δhc, is therefore identified. The proposed approach is applied to a large set of TiAl6V4 titanium-based samples with different roughness levels, polished by eleven silicon carbide sandpapers from grit paper 80 to 4,000. The result reveals that the scatter degree of the indentation curves is higher when the surface is rougher. The standard deviation of the shift Δhc is linearly connected to the standard deviation of the surface roughness, if the roughness is high-pass filtered in the scale of the indenter (15 µm). Using the proposed method, the estimated macro-hardness for eleven studied TiAl6V4 samples is in the range of 3.5–4.1 GPa, with the smallest deviation around 0.01 GPa, which is more accurate than the one given by the Nanoindentation MTS™ system, which uses an average value (around 4.3 ± 0.5 GPa). Moreover, the calculated Young's modulus of the material is around 136 ± 20 GPa, which is similar to the modulus in literature.
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Effect of surface roughness in the determination of the mechanical properties of material using Nanoindentation Test
Scanning, 2013Co-Authors: Y Xia, Pierre-emmanuel Mazeran, Maxence Bigerelle, J. Marteau, S. Bouvier, Alain IostAbstract:Summary A quantitative model is proposed for the estimation of macro-hardness using Nanoindentation Tests. It decreases the effect of errors related to the non-reproducibility of the Nanoindentation Test on calculations of macro-hardness by taking into account the indentation size effect and the surface roughness. The most innovative feature of this model is the simultaneous statistical treatment of all the Nanoindentation loading curves. The curve treatment mainly corrects errors in the zero depth determination by correlating their positions through the use of a relative reference. First, the experimental loading curves are described using the Bernhardt law. The fitted curves are then shifted, in order to simultaneously reduce the gaps between them that result from the scatter in the experimental curves. A set of shift depths, Δhc, is therefore identified. The proposed approach is applied to a large set of TiAl6V4 titanium-based samples with different roughness levels, polished by eleven silicon carbide sandpapers from grit paper 80 to 4,000. The result reveals that the scatter degree of the indentation curves is higher when the surface is rougher. The standard deviation of the shift Δhc is linearly connected to the standard deviation of the surface roughness, if the roughness is high-pass filtered in the scale of the indenter (15 µm). Using the proposed method, the estimated macro-hardness for eleven studied TiAl6V4 samples is in the range of 3.5–4.1 GPa, with the smallest deviation around 0.01 GPa, which is more accurate than the one given by the Nanoindentation MTS™ system, which uses an average value (around 4.3 ± 0.5 GPa). Moreover, the calculated Young's modulus of the material is around 136 ± 20 GPa, which is similar to the modulus in literature. SCANNING 36:134–149, 2014. © 2013 Wiley Periodicals, Inc.
Yueguang Wei - One of the best experts on this subject based on the ideXlab platform.
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nonuniformity effect of surface nanocrystalline materials in Nanoindentation Test
International Journal for Multiscale Computational Engineering, 2006Co-Authors: Yueguang Wei, X L Chen, S Q ShuAbstract:In the present research, microstructures of the surface-nanocrystalline Al alloy material are observed and measured based on the transmission electron microscopy (TEM) technique, and the corresponding mechanical behaviors are investigated experimentally and theoretically. In the experimental research, the Nanoindentation Test method is used, and the load and microhardness curves are measured, which strongly depend on the grain size and grain size nonuniformity. Two kinds of the Nanoindentation Test methods are adopted: the randomly selected loading point method and the continuous stiffness method. In the theoretical modeling, based on the microstructure characteristics of the surface-nanocrystalline Al alloy material, a dislocation pile-up model considering the grain size effect and based on the Mott theory is presented and used. The hardness-indent depth curves are predicted and modeled.
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size geometry and nonuniformity effects of surface nanocrystalline aluminum in Nanoindentation Test
International Journal of Plasticity, 2005Co-Authors: Yueguang Wei, Siqi Shu, Chen ZhuAbstract:In the present research, the mechanical behavior of the surface-nanocrystalline aluminum (SNCA) is investigated through Nanoindentation experiment and theoretical modeling. Firstly, through microscopical observation and measurement for the SNCA material, a microstructure cell model is developed. Secondly, based on the microstructure cell model and the strain gradient plasticity theory, and based on introducing a parameter accounting for the grain size nonuniformity effect, the discrete features of the hardness-depth relations of the SNCA material are described. The "U-type" feature of the hardness-depth experimental curves is modeled and simulated. Thirdly, in the SNCA material the mechanical property of the grain boundary, i.e., the strength of plastic zone penetrating the grain boundary is characterized by introducing a criterion parameter, the critical effective plastic strain. The "waterfall-type" feature of the hardness-depth curves is modeled and simulated. It is worth pointing out that, in the present study, the length scale parameter in the strain gradient plasticity theory is taken as a universal material parameter instead of a simulation parameter, and it is determined through applying the strain gradient plasticity theory to the modeling of the corresponding single crystal aluminum.
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Size effect measurement and characterization in Nanoindentation Test
Journal of Materials Research, 2004Co-Authors: Yueguang Wei, Xuezheng Wang, Manhong ZhaoAbstract:Nanoindentation Test at scale of hundreds of nanometers has shown that measured hardness increases strongly with decreasing indent depth, which is frequently referred to as the size effect. Usually, the size effect is displayed in the hardness-depth curves. In this study, the size effect is characterized in both the load–displacement curves and the hardness–depth curves. The experimental measurements were performed for single-crystal copper specimen and for surface-nanocrystallized Al-alloy specimen. Moreover, the size effect was characterized using the dislocation density theory. To investigate effects of some environmental factors, such as the effect of surface roughness and the effect of indenter tip curvature, the specimen surface profile and the indentation imprint profile for single-crystal copper specimen were scanned and measured using the atomic force microscopy technique. Furthermore, the size effect was characterized and analyzed when the effect of the specimen surface roughness was considered.
Maxence Bigerelle - One of the best experts on this subject based on the ideXlab platform.
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quantitative approach to determine the mechanical properties by Nanoindentation Test application on sandblasted materials
Tribology International, 2015Co-Authors: Y Xia, Maxence Bigerelle, Alain Iost, S Bouvier, Pierre-emmanuel MazeranAbstract:A novel method is developed to improve the accuracy in determining the mechanical properties from Nanoindentation curves. The key point of this method is the simultaneous statistical treatment of several loading curves to correct the zero point error and identify the material properties considering size effects. The method is applied to four sandblasted aluminum-based specimens with different surface roughness. A linear relationship is obtained between the standard deviation of the initial contact error and the roughness which highlights the effect of the surface roughness on the reproducibility of the indentation curves. Moreover, the smaller standard deviation of the hardness given by the method confirms the importance of considering the initial contact error for an accurate determination of the material properties.
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Effect of surface roughness in the determination of the mechanical properties of material using Nanoindentation Test
Scanning, 2014Co-Authors: Y Xia, Maxence Bigerelle, J. Marteau, P.-e. Mazeran, S. Bouvier, Alain IostAbstract:A quantitative model is proposed for the estimation of macro-hardness using Nanoindentation Tests. It decreases the effect of errors related to the non-reproducibility of the Nanoindentation Test on calculations of macro-hardness by taking into account the indentation size effect and the surface roughness. The most innovative feature of this model is the simultaneous statistical treatment of all the Nanoindentation loading curves. The curve treatment mainly corrects errors in the zero depth determination by correlating their positions through the use of a relative reference. First, the experimental loading curves are described using the Bernhardt law. The fitted curves are then shifted, in order to simultaneously reduce the gaps between them that result from the scatter in the experimental curves. A set of shift depths, Δhc, is therefore identified. The proposed approach is applied to a large set of TiAl6V4 titanium-based samples with different roughness levels, polished by eleven silicon carbide sandpapers from grit paper 80 to 4,000. The result reveals that the scatter degree of the indentation curves is higher when the surface is rougher. The standard deviation of the shift Δhc is linearly connected to the standard deviation of the surface roughness, if the roughness is high-pass filtered in the scale of the indenter (15 µm). Using the proposed method, the estimated macro-hardness for eleven studied TiAl6V4 samples is in the range of 3.5–4.1 GPa, with the smallest deviation around 0.01 GPa, which is more accurate than the one given by the Nanoindentation MTS™ system, which uses an average value (around 4.3 ± 0.5 GPa). Moreover, the calculated Young's modulus of the material is around 136 ± 20 GPa, which is similar to the modulus in literature.
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Effect of surface roughness in the determination of the mechanical properties of material using Nanoindentation Test
Scanning, 2013Co-Authors: Y Xia, Pierre-emmanuel Mazeran, Maxence Bigerelle, J. Marteau, S. Bouvier, Alain IostAbstract:Summary A quantitative model is proposed for the estimation of macro-hardness using Nanoindentation Tests. It decreases the effect of errors related to the non-reproducibility of the Nanoindentation Test on calculations of macro-hardness by taking into account the indentation size effect and the surface roughness. The most innovative feature of this model is the simultaneous statistical treatment of all the Nanoindentation loading curves. The curve treatment mainly corrects errors in the zero depth determination by correlating their positions through the use of a relative reference. First, the experimental loading curves are described using the Bernhardt law. The fitted curves are then shifted, in order to simultaneously reduce the gaps between them that result from the scatter in the experimental curves. A set of shift depths, Δhc, is therefore identified. The proposed approach is applied to a large set of TiAl6V4 titanium-based samples with different roughness levels, polished by eleven silicon carbide sandpapers from grit paper 80 to 4,000. The result reveals that the scatter degree of the indentation curves is higher when the surface is rougher. The standard deviation of the shift Δhc is linearly connected to the standard deviation of the surface roughness, if the roughness is high-pass filtered in the scale of the indenter (15 µm). Using the proposed method, the estimated macro-hardness for eleven studied TiAl6V4 samples is in the range of 3.5–4.1 GPa, with the smallest deviation around 0.01 GPa, which is more accurate than the one given by the Nanoindentation MTS™ system, which uses an average value (around 4.3 ± 0.5 GPa). Moreover, the calculated Young's modulus of the material is around 136 ± 20 GPa, which is similar to the modulus in literature. SCANNING 36:134–149, 2014. © 2013 Wiley Periodicals, Inc.
A. C. Fischer-cripps - One of the best experts on this subject based on the ideXlab platform.
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Critical review of analysis and interpretation of Nanoindentation Test data
Surface & Coatings Technology, 2005Co-Authors: A. C. Fischer-crippsAbstract:This paper reviews commonly used methods of analysing and interpreting Nanoindentation Test data, with a particular emphasis on the Testing of thin films. The popularity of Nanoindentation Testing is evidenced by the large number of papers that report such measurements in recent years. Unfortunately, there appear to be several issues that are emerging as common sources of error in using this technique. The present paper is aimed at highlighting these errors for the benefit of those practitioners who wish to use the technique but are not fully conversant with the field.
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Use of combined elastic modulus in the analysis of depth-sensing indentation data
Journal of Materials Research, 2001Co-Authors: A. C. Fischer-crippsAbstract:It is shown that the substitution of reduced modulus for specimen modulus in the analysis equations for Nanoindentation Test data is valid. The methods of analysis use the slope of the unloading force–depth response which is assumed to be elastic. Because of this utilization of the slope or unloading stiffness, it makes no difference whether or not the deflection of the indenter is accommodated explicitly or transferred to that occurring within the specimen by artificially reducing the specimen modulus from its true value to lower value, the reduced modulus.
