The Experts below are selected from a list of 300 Experts worldwide ranked by ideXlab platform

Yonghua Rong - One of the best experts on this subject based on the ideXlab platform.

  • Microstructural characterization of nanocrystalline nickel produced by surface mechanical attrition treatment
    Journal of Materials Science, 2009
    Co-Authors: Ping Liu, Yonghua Rong
    Abstract:

    By means of surface mechanical attrition treatment (SMAT), nanocrystalline surface layers are produced in pure Ni plates. The average crystallite size, root mean square (r.m.s.) microstrain, dislocation density, and Stored Elastic Energy are determined by X-ray diffraction (XRD) line profile analysis. The average crystallite size obtained by XRD is compared with the grain size observed from transmission electron microscopy (TEM) image. The high-resolution TEM (HRTEM) micrograph confirms the presence of high density of dislocations obtained by XRD, and reveals that most of dislocations distribute at the subgrain boundaries with few inside the subgrains.

  • Measurement of microstructural parameters of nanocrystalline Fe–30 wt.%Ni alloy produced by surface mechanical attrition treatment
    Journal of Alloys and Compounds, 2008
    Co-Authors: Xiaodong Wang, Yonghua Rong
    Abstract:

    Abstract Fe–30 wt.%Ni alloy was severely plastic deformed through surface mechanical attrition treatment (SMAT) for different times and the nanocrystalline surface layers were produced on surface. The microstructural parameters such as the average crystallite size, root mean square microstrain, dislocation density and Stored Elastic Energy were measured by using X-ray diffraction line profile analysis (XLPA) and transmission electron microscopy (TEM). The high values of dislocation density and Stored Elastic Energy were obtained in the SMAT samples. The average crystallite size measured by XLPA is compared with that observed on TEM. The high-resolution TEM (HRTEM) micrograph confirms the presence of high density of dislocations obtained by XLPA, accompanying the presence of heavy distortion of lattice, which is different from that in the tensile-deformed sample.

K. Wierzbanowski - One of the best experts on this subject based on the ideXlab platform.

  • Residual stress field in steel samples during plastic deformation and recovery processes
    Philosophical Magazine, 2011
    Co-Authors: Roman Wawszczak, Wilfrid Seiler, Andrzej Baczmanski, Chedly Braham, K. Wierzbanowski, Mirosław Wróbel, Alain Lodini
    Abstract:

    An X-ray diffraction method was applied to measure residual stresses and Stored Elastic Energy in deformed and annealed polycrystalline ferritic and austenitic steel samples. The orientation distribution of plastic incompatibility second-order stresses created during elastoplastic deformation was determined and presented in Euler space. Using deformation models, these stresses were correlated with different types of intergranular interactions occurring in the studied materials. An important decrease of the first- and the second-order residual stresses was observed during recovery and recrystallisation processes. Diffraction peak widths, related to dislocation density, were studied and correlated with stress variation during annealing process. Differences in stress relaxation between ferritic and austenitic samples were explained by different values of the stacking fault Energy, which influences dislocation climb and cross-slip.

  • Residual stress field in steel samples during plastic deformation and recovery processes
    Philosophical Magazine, 2011
    Co-Authors: Roman Wawszczak, Wilfrid Seiler, Andrzej Baczmanski, Chedly Braham, K. Wierzbanowski, Mirosław Wróbel, Alain Lodini
    Abstract:

    X-ray diffraction method was applied to measure residual stresses and Stored Elastic Energy in deformed and annealed polycrystalline ferritic and austenitic steel samples. Orientation distribution of incompatibility stresses created during elastoplastic deformation was determined and presented in Euler space. Using deformation models, the second order stresses were correlated with different types of intergranular interactions occurring in the studied materials. An important decrease of the first and the second order residual stresses was observed during recovery and recrystallization processes. Diffraction peaks related to dislocations density were studied and correlated with stress variation during annealing process. Differences in stress relaxation between ferritic and austenitic samples were explained by different values of the stacking fault Energy, which influences climb of dislocations.

  • Evolution of Residual Stresses and Stored Elastic Energy in Ferritic Steel during Recovery Process
    Materials Science Forum, 2010
    Co-Authors: Roman Wawszczak, Wilfrid Seiler, Andrzej Baczmanski, Chedly Braham, Mirosław Wróbel, K. Wierzbanowski
    Abstract:

    Diffraction method was applied to determine the residual stresses in deformed and annealed polycrystalline samples of ferritic steel. The specific Stored Elastic Energy corresponding to the grain stresses was calculated and presented in Euler space. An important decrease of the first and second order residual stresses and consequently Stored Elastic Energy was observed during recovery and recrystallization. The evolution of stresses was correlated with the variation of diffraction peak width (related to dislocations density) and crystallographical texture.

  • Plastic incompatibility stresses and Stored Elastic Energy in plastically deformed copper
    Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2009
    Co-Authors: Andrzej Baczmanski, Neila Hfaiedh, Manuel Francois, K. Wierzbanowski
    Abstract:

    Abstract The X-ray diffraction method and theoretical model of elastoplastic deformation were used to examine the residual stresses in polycrystalline copper. To this end, the {2 2 0} strain pole figures were determined for samples subjected to different magnitudes of tensile deformation. Using diffraction data and the self-consistent model, the tensor of plastic incompatibility stress was found for each orientation of a polycrystalline grain. Crystallographic textures, macroscopic and second-order residual stresses were considered in the analysis. As a result, the distributions of Elastic Stored Energy and von Mises equivalent stress were presented in Euler space and correlated with the preferred orientations of grains. Moreover, using the model prediction, the variation of the critical resolved shear stress with grain orientation was determined.

  • quantitative estimation of incompatibility stresses and Elastic Energy Stored in ferritic steel
    Journal of Applied Crystallography, 2008
    Co-Authors: Andrzej Baczmanski, K. Wierzbanowski, Paul Lipinski, Albert Tidu, B Pathiraj
    Abstract:

    Plastic incompatibility second-order stresses were determined for different orientations of a polycrystalline grain, using X-ray diffraction data and results of the self-consistent elasto-plastic model. The stresses in cold rolled ferritic steel were determined both in as-received and under tensile loaded conditions. It has been shown that the Reuss model and the self-consistent model applied to near surface volume provide the best approaches to determine diffraction Elastic constants. For the first time, the Elastic Energy in an anisotropic material (arising from plastic incompatibilities between grains having various lattice orientations) has been determined. The second-order incompatibility stresses and Stored Elastic Energy are presented in Euler space.

Andrzej Baczmanski - One of the best experts on this subject based on the ideXlab platform.

  • Residual stress field in steel samples during plastic deformation and recovery processes
    Philosophical Magazine, 2011
    Co-Authors: Roman Wawszczak, Wilfrid Seiler, Andrzej Baczmanski, Chedly Braham, K. Wierzbanowski, Mirosław Wróbel, Alain Lodini
    Abstract:

    An X-ray diffraction method was applied to measure residual stresses and Stored Elastic Energy in deformed and annealed polycrystalline ferritic and austenitic steel samples. The orientation distribution of plastic incompatibility second-order stresses created during elastoplastic deformation was determined and presented in Euler space. Using deformation models, these stresses were correlated with different types of intergranular interactions occurring in the studied materials. An important decrease of the first- and the second-order residual stresses was observed during recovery and recrystallisation processes. Diffraction peak widths, related to dislocation density, were studied and correlated with stress variation during annealing process. Differences in stress relaxation between ferritic and austenitic samples were explained by different values of the stacking fault Energy, which influences dislocation climb and cross-slip.

  • Residual stress field in steel samples during plastic deformation and recovery processes
    Philosophical Magazine, 2011
    Co-Authors: Roman Wawszczak, Wilfrid Seiler, Andrzej Baczmanski, Chedly Braham, K. Wierzbanowski, Mirosław Wróbel, Alain Lodini
    Abstract:

    X-ray diffraction method was applied to measure residual stresses and Stored Elastic Energy in deformed and annealed polycrystalline ferritic and austenitic steel samples. Orientation distribution of incompatibility stresses created during elastoplastic deformation was determined and presented in Euler space. Using deformation models, the second order stresses were correlated with different types of intergranular interactions occurring in the studied materials. An important decrease of the first and the second order residual stresses was observed during recovery and recrystallization processes. Diffraction peaks related to dislocations density were studied and correlated with stress variation during annealing process. Differences in stress relaxation between ferritic and austenitic samples were explained by different values of the stacking fault Energy, which influences climb of dislocations.

  • Evolution of Residual Stresses and Stored Elastic Energy in Ferritic Steel during Recovery Process
    Materials Science Forum, 2010
    Co-Authors: Roman Wawszczak, Wilfrid Seiler, Andrzej Baczmanski, Chedly Braham, Mirosław Wróbel, K. Wierzbanowski
    Abstract:

    Diffraction method was applied to determine the residual stresses in deformed and annealed polycrystalline samples of ferritic steel. The specific Stored Elastic Energy corresponding to the grain stresses was calculated and presented in Euler space. An important decrease of the first and second order residual stresses and consequently Stored Elastic Energy was observed during recovery and recrystallization. The evolution of stresses was correlated with the variation of diffraction peak width (related to dislocations density) and crystallographical texture.

  • Plastic incompatibility stresses and Stored Elastic Energy in plastically deformed copper
    Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2009
    Co-Authors: Andrzej Baczmanski, Neila Hfaiedh, Manuel Francois, K. Wierzbanowski
    Abstract:

    Abstract The X-ray diffraction method and theoretical model of elastoplastic deformation were used to examine the residual stresses in polycrystalline copper. To this end, the {2 2 0} strain pole figures were determined for samples subjected to different magnitudes of tensile deformation. Using diffraction data and the self-consistent model, the tensor of plastic incompatibility stress was found for each orientation of a polycrystalline grain. Crystallographic textures, macroscopic and second-order residual stresses were considered in the analysis. As a result, the distributions of Elastic Stored Energy and von Mises equivalent stress were presented in Euler space and correlated with the preferred orientations of grains. Moreover, using the model prediction, the variation of the critical resolved shear stress with grain orientation was determined.

  • quantitative estimation of incompatibility stresses and Elastic Energy Stored in ferritic steel
    Journal of Applied Crystallography, 2008
    Co-Authors: Andrzej Baczmanski, K. Wierzbanowski, Paul Lipinski, Albert Tidu, B Pathiraj
    Abstract:

    Plastic incompatibility second-order stresses were determined for different orientations of a polycrystalline grain, using X-ray diffraction data and results of the self-consistent elasto-plastic model. The stresses in cold rolled ferritic steel were determined both in as-received and under tensile loaded conditions. It has been shown that the Reuss model and the self-consistent model applied to near surface volume provide the best approaches to determine diffraction Elastic constants. For the first time, the Elastic Energy in an anisotropic material (arising from plastic incompatibilities between grains having various lattice orientations) has been determined. The second-order incompatibility stresses and Stored Elastic Energy are presented in Euler space.

G Patriarche - One of the best experts on this subject based on the ideXlab platform.

Ping Liu - One of the best experts on this subject based on the ideXlab platform.

  • Microstructural characterization of nanocrystalline nickel produced by surface mechanical attrition treatment
    Journal of Materials Science, 2009
    Co-Authors: Ping Liu, Yonghua Rong
    Abstract:

    By means of surface mechanical attrition treatment (SMAT), nanocrystalline surface layers are produced in pure Ni plates. The average crystallite size, root mean square (r.m.s.) microstrain, dislocation density, and Stored Elastic Energy are determined by X-ray diffraction (XRD) line profile analysis. The average crystallite size obtained by XRD is compared with the grain size observed from transmission electron microscopy (TEM) image. The high-resolution TEM (HRTEM) micrograph confirms the presence of high density of dislocations obtained by XRD, and reveals that most of dislocations distribute at the subgrain boundaries with few inside the subgrains.