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A. Fawzy - One of the best experts on this subject based on the ideXlab platform.
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effect of Grain Diameter strain rate and deformation temperature on the work hardening characteristics of al 0 86 wt mn 0 28 wt fe
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2008Co-Authors: A. FawzyAbstract:Abstract Stress–strain characteristics of Al–0.86 wt%Mn–0.28 wt%Fe specimens with different Grain Diameters were studied in the temperature range from 300 to 393 K. Tensile tests were performed at different strain rates ranged from e ˙ = 2.2 × 10−4 to 1.0 × 10−2 s−1. The work hardening parameters; yield stress σy, fracture stress σf, strain hardening exponent n, and the total elongation ɛT were found to be markedly affected by the strain rate e ˙ , deformation temperature T and Grain Diameter D of the tested sample. From the Grain Diameter dependence of these hardening parameters, two distinct stages were observed. In the first stage, increasing D results in increased σy, σf, n and ɛT to maxima at ∼53 μm. In the second stage, these parameters drastically decreased with further increase of D. The decrease of σy with D in the second stage reaches its minimum (σy,min) at values depend on the strain rate e ˙ . Both σy and σy,min were found to increase with increasing e ˙ while ɛT decreased. The obtained results were interpreted on the basis of solid solution decomposition caused by annealing treatment. The Grain Diameter dependence of the work hardening parameters may characterize a dislocation movement by cross slip mechanism. The microstructure of the tested samples was examined by optical microscopy and X-ray diffraction measurements.
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Effect of Grain Diameter, strain rate and deformation temperature on the work hardening characteristics of Al–0.86 wt%Mn–0.28 wt%Fe
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2007Co-Authors: A. FawzyAbstract:Abstract Stress–strain characteristics of Al–0.86 wt%Mn–0.28 wt%Fe specimens with different Grain Diameters were studied in the temperature range from 300 to 393 K. Tensile tests were performed at different strain rates ranged from e ˙ = 2.2 × 10−4 to 1.0 × 10−2 s−1. The work hardening parameters; yield stress σy, fracture stress σf, strain hardening exponent n, and the total elongation ɛT were found to be markedly affected by the strain rate e ˙ , deformation temperature T and Grain Diameter D of the tested sample. From the Grain Diameter dependence of these hardening parameters, two distinct stages were observed. In the first stage, increasing D results in increased σy, σf, n and ɛT to maxima at ∼53 μm. In the second stage, these parameters drastically decreased with further increase of D. The decrease of σy with D in the second stage reaches its minimum (σy,min) at values depend on the strain rate e ˙ . Both σy and σy,min were found to increase with increasing e ˙ while ɛT decreased. The obtained results were interpreted on the basis of solid solution decomposition caused by annealing treatment. The Grain Diameter dependence of the work hardening parameters may characterize a dislocation movement by cross slip mechanism. The microstructure of the tested samples was examined by optical microscopy and X-ray diffraction measurements.
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Effect of Grain Diameter on the work-hardening characteristics of Zn–1 wt.% Cu alloy during phase transformation
Materials Characterization, 2007Co-Authors: A. Fawzy, M. SobhyAbstract:Abstract Stress–strain characteristics of slowly cooled Zn–1 wt.% Cu alloy specimens with different Grain Diameters have been studied in the temperature range from 453 to 573 K. The work-hardening parameters; coefficient of work-hardening, χp, yield stress, σy, and fracture stress, σf of the investigated specimens were found to decrease in a non-monotonic behaviour with increasing the deformation temperature. Two decreasing stages were observed before and after the transformation temperature 513 K. The rate of change of these parameters as well as the strain hardening exponent n (= d lnσ/d lne) were investigated as function of deformation temperature. They showed two different behaviours before and after the transformation temperature. The effect of Grain Diameter on the above work-hardening parameters were also taken into consideration. The work-hardening parameters were found to increase with increasing Grain Diameter while the strain hardening exponent n is decreased. The obtained results were interpreted on the basis of the coarsening of e-phase at the early stages of the first temperature range while the second stage referred to the thermal agitation of dislocation motion. The two observed temperature regions below and above 513 K may characterize a point of dislocation intersection mechanisms activated with ∼0.2 eV for the two regions. The microstructure of the samples under investigation was examined by optical microscopy (OM).
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effect of Grain Diameter on the tensile characteristics of thermally deformed ag 4 4 wt cu alloy
Physica B-condensed Matter, 2006Co-Authors: A. Fawzy, R.h. NadaAbstract:Abstract Tensile characteristics of Ag-4.4 wt% Cu specimens of different Grain Diameters were investigated at 300, 343, 383, 423 and 463 K. It was found that the strain hardening exponent n, resilience Uy and strain rate e ˙ were increased with increasing Grain Diameter while a decrease in the yield stress σ y , fracture stress σ f and toughness Uf were observed. This was explained in view of the dislocation interaction with the defects and different inclusions in the matrix and the formation of twins. The formation of twins was found accompanied by an abrupt increase in the strain per unit stress ( e / σ ) at a critical stress σ c . The value of σ c was found to decrease with the increase of Grain Diameter d. Concentration of the deformation twins was also found to decrease with increasing the Grain Diameter d. The associated atomic rearrangement during the formation of deformation twins was found thermally activated by activation energy of ∼0.2 eV. The microstructure of Ag-4.4 wt% Cu alloy specimens was performed by optical microscopy.
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Effect of Grain Diameter on the tensile characteristics of thermally deformed Ag-4.4 wt% Cu alloy
Physica B: Condensed Matter, 2006Co-Authors: A. Fawzy, R.h. NadaAbstract:Abstract Tensile characteristics of Ag-4.4 wt% Cu specimens of different Grain Diameters were investigated at 300, 343, 383, 423 and 463 K. It was found that the strain hardening exponent n, resilience Uy and strain rate e ˙ were increased with increasing Grain Diameter while a decrease in the yield stress σ y , fracture stress σ f and toughness Uf were observed. This was explained in view of the dislocation interaction with the defects and different inclusions in the matrix and the formation of twins. The formation of twins was found accompanied by an abrupt increase in the strain per unit stress ( e / σ ) at a critical stress σ c . The value of σ c was found to decrease with the increase of Grain Diameter d. Concentration of the deformation twins was also found to decrease with increasing the Grain Diameter d. The associated atomic rearrangement during the formation of deformation twins was found thermally activated by activation energy of ∼0.2 eV. The microstructure of Ag-4.4 wt% Cu alloy specimens was performed by optical microscopy.
Xiaojing Zheng - One of the best experts on this subject based on the ideXlab platform.
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Influence of sand Grain Diameter and wind velocity on lift-off velocities of sand particles
The European physical journal. E Soft matter, 2013Co-Authors: Xiaojing Zheng, Shao-zhen Duan, Yi-rui LiangAbstract:In this paper, the velocities of sand particles near the sand bed in the saltation cloud were measured in a wind tunnel through an improved experimental scheme of the Particle Image Velocimetry (PIV) system. The influences of the Diameter of sand particles in the saltation cloud and wind velocity on the probability distribution function (PDF) of lift-off velocities of sand particles were investigated. Results demonstrate that for the sand particles saltating above the sand bed with the mean Grain Diameter (d m = 0.3 mm), smaller and larger ones have the same velocity distribution, and wind velocity has no obvious influence on the distribution shape of the lift-off velocities, i.e., the PDFs of the horizontal and vertical lift-off velocities both follow a lognormal distribution, but the Diameter of sand particles in the saltation cloud and wind velocity have an influence on the parameters of the PDF of horizontal and vertical lift-off velocities. Eventually, we present formulas to describe the PDF of lift-off velocities of sand particles with regard to the influence of wind velocity and the Diameter of sand particles in the saltation cloud above the sand bed with d m = 0.3 mm.
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The influence of wind velocity and sand Grain Diameter on the falling velocities of sand particles
Powder Technology, 2013Co-Authors: Xiaojing Zheng, Shao-zhen Duan, Yi-rui LiangAbstract:Abstract In this paper, sand velocities near the sand bed in aeolian sand transport were measured in a wind tunnel through an improved experimental scheme of the Particle Image Velocimetry (PIV) system and a data processing method. The influences of wind velocity and sand Grain Diameter on the probability distribution of the falling velocities of sand particles were investigated. Results demonstrate that wind velocity and sand Grain Diameter have no obvious influence on the distribution pattern of the falling velocities of sand particles, i.e., the probability distributions of the horizontal and vertical falling velocities of sand particles follow a Gaussian distribution and a negative exponential distribution respectively, but wind velocity has an influence on the center, width and amplitude of the probability distribution of the horizontal falling velocities of sand particles, as well as the decay constant and amplitude of the probability distribution of the vertical falling velocities of sand particles. Eventually, we presented formulas to describe the probability distribution of the falling velocities of sand particles with regard to the influence of wind velocity.
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Impact of Grain sizes on phonon thermal conductivity of bulk thermoelectric materials
Applied Physics Letters, 2005Co-Authors: Xiaojing Zheng, Linli Zhu, Youhe Zhou, Qingjie ZhangAbstract:We report a phonon transport model for a bulk thermoelectric material to investigate the effect of the Grain Diameter and the Grain-boundary thickness on its thermal conductivity. The analysis results display that the bulk thermal conductivity is significantly reduced by decreasing the Grain sizes when the Grain Diameter is less than 500nm, which provides us one feasible way to enhance the figure of merit ZT of the material, and the thermal conductivity is mainly attributed to the contribution of Grains, while the Grain-boundary thermal conductivity has to be considered when the Grain Diameter is less than 100nm.
Yi-rui Liang - One of the best experts on this subject based on the ideXlab platform.
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Influence of sand Grain Diameter and wind velocity on lift-off velocities of sand particles
The European physical journal. E Soft matter, 2013Co-Authors: Xiaojing Zheng, Shao-zhen Duan, Yi-rui LiangAbstract:In this paper, the velocities of sand particles near the sand bed in the saltation cloud were measured in a wind tunnel through an improved experimental scheme of the Particle Image Velocimetry (PIV) system. The influences of the Diameter of sand particles in the saltation cloud and wind velocity on the probability distribution function (PDF) of lift-off velocities of sand particles were investigated. Results demonstrate that for the sand particles saltating above the sand bed with the mean Grain Diameter (d m = 0.3 mm), smaller and larger ones have the same velocity distribution, and wind velocity has no obvious influence on the distribution shape of the lift-off velocities, i.e., the PDFs of the horizontal and vertical lift-off velocities both follow a lognormal distribution, but the Diameter of sand particles in the saltation cloud and wind velocity have an influence on the parameters of the PDF of horizontal and vertical lift-off velocities. Eventually, we present formulas to describe the PDF of lift-off velocities of sand particles with regard to the influence of wind velocity and the Diameter of sand particles in the saltation cloud above the sand bed with d m = 0.3 mm.
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The influence of wind velocity and sand Grain Diameter on the falling velocities of sand particles
Powder Technology, 2013Co-Authors: Xiaojing Zheng, Shao-zhen Duan, Yi-rui LiangAbstract:Abstract In this paper, sand velocities near the sand bed in aeolian sand transport were measured in a wind tunnel through an improved experimental scheme of the Particle Image Velocimetry (PIV) system and a data processing method. The influences of wind velocity and sand Grain Diameter on the probability distribution of the falling velocities of sand particles were investigated. Results demonstrate that wind velocity and sand Grain Diameter have no obvious influence on the distribution pattern of the falling velocities of sand particles, i.e., the probability distributions of the horizontal and vertical falling velocities of sand particles follow a Gaussian distribution and a negative exponential distribution respectively, but wind velocity has an influence on the center, width and amplitude of the probability distribution of the horizontal falling velocities of sand particles, as well as the decay constant and amplitude of the probability distribution of the vertical falling velocities of sand particles. Eventually, we presented formulas to describe the probability distribution of the falling velocities of sand particles with regard to the influence of wind velocity.
R.h. Nada - One of the best experts on this subject based on the ideXlab platform.
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effect of Grain Diameter on the tensile characteristics of thermally deformed ag 4 4 wt cu alloy
Physica B-condensed Matter, 2006Co-Authors: A. Fawzy, R.h. NadaAbstract:Abstract Tensile characteristics of Ag-4.4 wt% Cu specimens of different Grain Diameters were investigated at 300, 343, 383, 423 and 463 K. It was found that the strain hardening exponent n, resilience Uy and strain rate e ˙ were increased with increasing Grain Diameter while a decrease in the yield stress σ y , fracture stress σ f and toughness Uf were observed. This was explained in view of the dislocation interaction with the defects and different inclusions in the matrix and the formation of twins. The formation of twins was found accompanied by an abrupt increase in the strain per unit stress ( e / σ ) at a critical stress σ c . The value of σ c was found to decrease with the increase of Grain Diameter d. Concentration of the deformation twins was also found to decrease with increasing the Grain Diameter d. The associated atomic rearrangement during the formation of deformation twins was found thermally activated by activation energy of ∼0.2 eV. The microstructure of Ag-4.4 wt% Cu alloy specimens was performed by optical microscopy.
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Effect of Grain Diameter on the tensile characteristics of thermally deformed Ag-4.4 wt% Cu alloy
Physica B: Condensed Matter, 2006Co-Authors: A. Fawzy, R.h. NadaAbstract:Abstract Tensile characteristics of Ag-4.4 wt% Cu specimens of different Grain Diameters were investigated at 300, 343, 383, 423 and 463 K. It was found that the strain hardening exponent n, resilience Uy and strain rate e ˙ were increased with increasing Grain Diameter while a decrease in the yield stress σ y , fracture stress σ f and toughness Uf were observed. This was explained in view of the dislocation interaction with the defects and different inclusions in the matrix and the formation of twins. The formation of twins was found accompanied by an abrupt increase in the strain per unit stress ( e / σ ) at a critical stress σ c . The value of σ c was found to decrease with the increase of Grain Diameter d. Concentration of the deformation twins was also found to decrease with increasing the Grain Diameter d. The associated atomic rearrangement during the formation of deformation twins was found thermally activated by activation energy of ∼0.2 eV. The microstructure of Ag-4.4 wt% Cu alloy specimens was performed by optical microscopy.
M Doi - One of the best experts on this subject based on the ideXlab platform.
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Effect of Grain Diameter on iron loss properties of non-oriented silicon steel sheets
Journal of Magnetism and Magnetic Materials, 2000Co-Authors: H Denma, Yoshiyuki Ishihara, Toshiyuki Todaka, M DoiAbstract:Abstract The iron loss properties of the non-oriented silicon steel sheets as a function thickness, silicon contents, cutting angle and Grain Diameter were measured by single-sheet tester (SST). The specimens were excited by sinusoidal waveform (50 Hz), fundamental waveform (50 Hz) with a single high-order harmonic component and PWM waveform. The averaging loss of three directions is defined as ( L +2× C + T )/4 (called as A3D loss). The increase ratio of non-sinusoidal waveform exciting condition’s A3D loss against the sinusoidal waveform one was different despite the equal levels of the A3D loss under sinusoidal waveform exciting condition. This is because it depends on a difference of iron loss constitution.
