Dependence of Measured Lateral Stress on Thickness of Protective “Padding” around Gauge

Hammond, R. I.; Church, P.; Grief, A.; Proud, W. G.; Field, J. E.

doi:10.1063/1.1780436

Cited by 6 publications

(5 citation statements)

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“…It could also be that the ε-phase is weaker. Interestingly in pure single-crystal α-iron, the spall strength was found to increase at the phase transition stress (Hammond et al . 2003), this observation agreeing with previous work (Murray 1996).…”

Section: Discussionmentioning

confidence: 99%

“…There was also concern that using such a large quantity of mylar might affect the stress level in the gauge. The effect of 'padding' the gauge in this has been quantified (Hammond et al . 2003) and hence can be taken account of.…”

Section: Discussionmentioning

confidence: 99%

“…Studies of the survivability of lateral gauges are ongoing, these involve incorporating extra 'padding' around the gauge. The effect of different degrees of this 'padding' has been quantified (Hammond et al . 2003).…”

Section: (A) Static Datamentioning

confidence: 99%

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Does the pressure‐induced a ‐ e phase transition occur for all low–alloy steels?

Hammond

Proud

2004

Proc. R. Soc. Lond. A

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When designing many products, especially vehicles, it is important to take into consideration impact properties. This paper presents fundamental dynamic data for two examples of bainitic steels. Hugoniots and shear-strength variation with longitudinal stress is reported. These were similar for both materials and in agreement with values for mild steel. The ferrite in the lower-temperature bainite was found to undergo a shock-induced phase transition at 13 GPa, whereas no phase transition was observed in the upper bainite. Further research is being conducted to account for this difference by studying the microstructure and the effect of impact on it. The lower-temperature bainite was found to behave in a brittle fashion, fragmenting extremely, whereas upper bainitic samples were usually recovered intact indicating ductile behaviour. The dynamic tensile or spall strength was also measured in these materials over a range of impact conditions. For the upper bainite, the spall strength dropped slightly with increasing longitudinal stress. However, for the lower-temperature bainite, there was a significant drop in spall strength above the longitudinal stress at which the phase transition occurs. Microstructural studies were also undertaken.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Does the pressure‐induced a ‐ e phase transition occur for all low–alloy steels?

Hammond

Proud

2004

Proc. R. Soc. Lond. A

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“…One 25 mm mylar sheet was placed on each side of the lateral gauge packages to improve gauge survivability. Any systematic error introduced by mylar is small compared with other experimental uncertainties [24]. Table 4 describes the different plate impact configurations that were used in this investigation.…”

Section: Plate Impact Experimental Detailsmentioning

confidence: 99%

“…Both gauges failed in experiment KLa6, showing that lateral gauges in TKB do not function reliably at axial stresses of 4.7 GPa. Lateral gauges have failed at high pressures in other materials [24].…”

Section: Article In Pressmentioning

confidence: 99%

The shock Hugoniot of Tuffisitic Kimberlite Breccia

Willmott¹,

Proud²

2007

International Journal of Rock Mechanics and Mining Sciences

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High-pressure tailored compression: Controlled thermodynamic paths

Nguyen

Orlikowski

Streitz

et al. 2006

Journal of Applied Physics

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We have recently carried out novel and exploratory dynamic experiments where the sample follows a prescribed thermodynamic path. In typical dynamic compression experiments, the samples are thermodynamically limited to the principal Hugoniot or quasi-isentrope. With recent developments in the functionally graded material impactor, we can prescribe and shape the applied pressure profile with similarly-shaped, non-monotonic impedance profile in the impactor. Previously inaccessible thermodynamic states beyond the quasi-isentropes and Hugoniot can now be reached in dynamic experiments with these impactors. In the light gas-gun experiments on copper reported here, we recorded the particle velocities of the Cu-LiF interfaces and employed hydrodynamic simulations to relate them to the thermodynamic phase diagram. Peak pressures for these experiments were on the order of megabars, and the time-scales ranged from nanoseconds to several microseconds. The strain rates of the quasi-isentropic experiments are approximately 10 4 s −1 to 10 6 s −1 in samples with thicknesses up to 5 mm. Though developed at a light-gas gun facility, such shaped pressure-profiles are also feasible in principle with laser ablation or magnetic driven compression techniques allowing for new directions to be taken in high pressure physics. 62.50.+p; 1 The ability to attain extreme pressure and temperature conditions has given investigators in fields as diverse as biology, condensed matter physics, and earth and planetary sciences the tools to explore material behavior at megabar pressures and at thousands of degrees [1][2][3][4][5][6][7][8][9][10][11][12][13]. With these tools, they have simulated the physical conditions in the Earth's core and planetary interiors [1,2], probed a wide range of high pressure and temperature material properties [5][6][7][8][9][10], synthesized novel materials [11,12], and solved long standing physics problems such as the metallization of hydrogen [13]. These extreme conditions were achieved through three main techniques: static, shock and quasi-isentropic compressions [13][14][15][16][17][18][19][20][21][22][23][24]. Since the pioneering work by P. W. Bridgman [25], advances in diamond anvil cell technology have pushed the peak pressure by static compression from 200 kbars to more than 4 megabars [21,22]. Similarly, shock compression and quasi-isentropic compression techniques [13][14][15][16][17][18][19][20] can load samples to megabar pressures in a fraction of a nanosecond to microseconds.Future advances will likely push the peak pressure higher and extend the pressure loading time. However, these techniques will continue to be limited to a portion of the high pressure phase diagram by their characteristic loading rate and a single thermodynamic path. In particular, static compression yields continuous states on an isotherm (or an isochore, when heating), with a slow loading rate of˙ < 10 1 s −1 . Shock compression rapidly loads a sample at strain rates of˙ > ∼ 10 9 s −1 to a single state on the Hugoniot -...

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Dependence of Measured Lateral Stress on Thickness of Protective “Padding” around Gauge

Cited by 6 publications

References 3 publications

Does the pressure‐induced a ‐ e phase transition occur for all low–alloy steels?

Does the pressure‐induced a ‐ e phase transition occur for all low–alloy steels?

The shock Hugoniot of Tuffisitic Kimberlite Breccia

High-pressure tailored compression: Controlled thermodynamic paths

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