The Experts below are selected from a list of 59310 Experts worldwide ranked by ideXlab platform
Philip J. Rae - One of the best experts on this subject based on the ideXlab platform.
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The properties of poly(tetrafluoroethylene) (PTFE) in tension
Polymer, 2005Co-Authors: Philip J. Rae, E. N. BrownAbstract:Samples of DuPont 7A and 7C Teflon (PTFE, poly(tetrafluoroethylene)) were tested in tension at strain-rates between 2×10-4and 0.1 s-1and temperatures between -50 and 150 °C. Additionally, using a Hopkinson bar, a temperature series was undertaken in tension between -50 and 23 °C at a strain rate of 800 s-1. To investigate the small-strain response, strain gauges were used to measure axial and transverse strain allowing the Poisson Ratio to be calculated. The effect of crystallinity was investigated using 7C material thermally processed to produce more amorphous material. As expected, the tensile mechanical properties of PTFE are significantly affected by strain-rate and temperature, but only to a limited extent by crystallinity. The Poisson Ratio at small strains was found to differ in tension (≈0.36) and compression (≈0.46). Failure behavior and microstructure were correlated to temperature induced phase transitions. © 2005 Elsevier Ltd. All rights reserved.
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The properties of poly(tetrafluoroethylene) (PTFE) in compression
Polymer, 2004Co-Authors: Philip J. Rae, Dana M. DattelbaumAbstract:Samples of DuPont 7A and 7C Teflon (PTFE, poly(tetrafluoroethylene)) were tested in compression at strain-rates between 10-4and 1 s-1and temperatures between -198 and 200°C. Additionally, using a Split-Hopkinson pressure bar, a temperature compression series was undertaken between -100 and 150°C at a strain rate of 3200 s-1. To investigate the small-strain response, strain gauges were used to measure axial and transverse strain allowing the Poisson Ratio to be quantified. As expected, the mechanical properties were found to be strongly affected by strain-rate and temperature. Moduli were found by several methods and the trend, with respect to temperature, lends weight to the suggestion that the glass-transition temperature of PTFE is ≈-100°C. The physical properties of the sintered PTFE were measured and the crystallinities measured by several techniques. © 2004 Elsevier Ltd. All rights reserved.
Dana M. Dattelbaum - One of the best experts on this subject based on the ideXlab platform.
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The properties of poly(tetrafluoroethylene) (PTFE) in compression
Polymer, 2004Co-Authors: Philip J. Rae, Dana M. DattelbaumAbstract:Samples of DuPont 7A and 7C Teflon (PTFE, poly(tetrafluoroethylene)) were tested in compression at strain-rates between 10-4and 1 s-1and temperatures between -198 and 200°C. Additionally, using a Split-Hopkinson pressure bar, a temperature compression series was undertaken between -100 and 150°C at a strain rate of 3200 s-1. To investigate the small-strain response, strain gauges were used to measure axial and transverse strain allowing the Poisson Ratio to be quantified. As expected, the mechanical properties were found to be strongly affected by strain-rate and temperature. Moduli were found by several methods and the trend, with respect to temperature, lends weight to the suggestion that the glass-transition temperature of PTFE is ≈-100°C. The physical properties of the sintered PTFE were measured and the crystallinities measured by several techniques. © 2004 Elsevier Ltd. All rights reserved.
Eloi Pineda - One of the best experts on this subject based on the ideXlab platform.
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Elastic properties behaviour of metallic glasses
Reviews on Advanced Materials Science, 2008Co-Authors: Eloi Pineda, Wei Hua Wang, Daniel CrespoAbstract:Estimating a fictive temperature of the glasses by means of their values of Tg, the glass elastic properties are interpreted in terms of the elastic behaviour of the equilibrium liquid above the glass transition. A correlation between the Poisson Ratio of the glass and the anharmonic properties of the supercooled liquid is proposed. ? 2008 Advanced Study Center Co. Ltd.
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Theoretical approach to Poisson Ratio behavior during structural changes in metallic glasses
Physical Review B - Condensed Matter and Materials Physics, 2006Co-Authors: Eloi PinedaAbstract:Recently, various studies dealing with the relationship between the elastic constants and various of the macroscopic properties of metallic glasses have been published. Particularly, the correlations between Poisson’s Ratio of the glass and both the super cooled liquid viscosity behavior and the brittle-ductile transition have aroused much interest. We use a model developed by Knuyt et al. (1990 and 1991) based on a Gaussian distribution for the nearest-neighbor distance in an ideal unicomponent metallic glass in order to describe qualitatively the dependence of Poisson Ratio on changes of the atomic structure. The results are used to explain the experimental results obtained in structural relaxation and hydrostatic pressure tests of metallic glasses.
E. N. Brown - One of the best experts on this subject based on the ideXlab platform.
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The properties of poly(tetrafluoroethylene) (PTFE) in tension
Polymer, 2005Co-Authors: Philip J. Rae, E. N. BrownAbstract:Samples of DuPont 7A and 7C Teflon (PTFE, poly(tetrafluoroethylene)) were tested in tension at strain-rates between 2×10-4and 0.1 s-1and temperatures between -50 and 150 °C. Additionally, using a Hopkinson bar, a temperature series was undertaken in tension between -50 and 23 °C at a strain rate of 800 s-1. To investigate the small-strain response, strain gauges were used to measure axial and transverse strain allowing the Poisson Ratio to be calculated. The effect of crystallinity was investigated using 7C material thermally processed to produce more amorphous material. As expected, the tensile mechanical properties of PTFE are significantly affected by strain-rate and temperature, but only to a limited extent by crystallinity. The Poisson Ratio at small strains was found to differ in tension (≈0.36) and compression (≈0.46). Failure behavior and microstructure were correlated to temperature induced phase transitions. © 2005 Elsevier Ltd. All rights reserved.
N. Chen - One of the best experts on this subject based on the ideXlab platform.
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Superductile bulk metallic glass
Applied Physics Letters, 2006Co-Authors: K. F. Yao, Y. Q. Yang, F. Ruan, N. ChenAbstract:We report on experimental evidence of pronounced global plasticity measured in monolithic Pt57.5Cu14.7Ni5.3P22.5 bulk metallic glass under both bending and unconfined compression loading conditions. A plastic strain of 20% is measured, never before seen in metallic glasses. Also, permanent deformation and a strain exceeding 3% before failure is observed during bending of 4 mm thick samples. To date, no monolithic metallic material has exhibited such a combination of high strength, extensive ductility, and high elastic limit. The large plasticity is reflected in a high Poisson Ratio of 0.42, which causes the tip of a shear band to extend rather than initiate a crack. This results in the formation of multiple shear bands and is the origin of the observed large global ductility and very high fracture toughness, approximately 80 MPa m(-1/2).
