高压物理学报

Conversion of Graphite-to-Diamond Assisted by a Fluid Catalyst under High Pressure and High Temperature

WU Qi, SUN Li-Ling, JING Qin, CAO Xin-Cheng, WANG Wen-Kui

2002, 16(1): 1-6 . doi: 10.11858/gywlxb.2002.01.001

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Abstract:
The catalyst role of supercritical fluid CO2 in the conversion of graphite-to-diamond at high pressure and high temperature has been confirmed experimentally. The complete transformation from graphite to diamond is achieved at 1 800～2 000 ℃ within 2～0.5 h under the pressure of 7.7 GPa. The change in temperature leads to morphology modification of the diamonds formed in the experiments: Diamonds with an irregular shape crystallize at 1 800～2 000 ℃ and the octahedral morphology crystallize at 1 500～1 700 ℃.

Application of PVDF for Thermal Shock Wave Measurement in Materials Radiated by Electron Beam

PENG Chang-Xian, LIN Peng, TAN Hong-Mei, TANG Yu-Zhi, LIU Xiao-Ling

2002, 16(1): 7-16 . doi: 10.11858/gywlxb.2002.01.002

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Abstract:
In this paper, the propagating characteristics of thermal shock waves induced by electron beam are investigated experimentally using PVDF piezoelectric gauges. Experimental results indicate: (1) As energy flux is between 90 and 210 J/cm2, peak stress of thermal shock waves in weave material and it's parted material is below 0.1 GPa, which is less than one tenth of that in LY12Al; (2) Action time in weave material is obviously widened, and it's average value is 2.6 s, which is more than 7 times of that in LY12Al. The experimental results show: (1) The wave material has excellent characteristics of dissipating and widening thermal shock waves; (2) PVDF piezoelectric gauges can be used to measure the thermal shock waves in weave material, which has long action time.

Comprehensive Evaluations of Mechanical Parameters for 93W Alloy

HUA Jing-Song, JING Fu-Qian, TAN Hua, SHEN Zhong-Yi, ZHANG Han-Zhao

2002, 16(1): 17-21 . doi: 10.11858/gywlxb.2002.01.003

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Abstract:
This article reports the new ultrasonic data of 93W (a tungsten alloy with 4.3% Ni, 2.45% Fe and 0.35% Co by weight as binder) obtained using different apparatus. We further made some analyses and comparisons with some previous data, including ultrasonic data and Hugoniot parameters, which were measured in our laboratory in the past. As a result, the recommended mechanical parameters approximately suitable for 93W are as follows: G0=132 GPa, Gp=1.79, GT=-0.016 GPa/℃, K0=270 GPa, and Kp=4.11.

Dynamic Response of Polycrystalline Alumina under Shock Loading

LI Ping, LI Da-Hong, NING Jian-Guo, JING Fu-Qian

2002, 16(1): 22-28 . doi: 10.11858/gywlxb.2002.01.004

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Abstract:
The dynamic responses of polycrystalline alumina under plate impact were studied in the pressure range of 0～11.0 GPa experimentally using VISAR and in-material maganin gauges. The Hugoniot-elastic limit (HEL), compressive yield strength (Yc), Hugoniot sound speed and Hugoniot curve were obtained. Both free surface velocity profiles and Hugoniot curves indicate the dispersion of the permanent deformation wave for this material in the pressure range.

Numerical Simulation of Initiation of PBX-9404 Impacted By Round-Nosed Steel Projectiles

ZHENG Ping-Gang, ZHAO Feng, ZHANG Zhen-Yu

2002, 16(1): 29-33 . doi: 10.11858/gywlxb.2002.01.005

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Abstract:
Shock initiation behaviors of PBX-9404 impacted by round-nosed steel projectiles were studied numerically by means of adding two kinds of reaction-rate into two-dimensional finite element code DYNA2D.

The Dynamic Model of Vitreous Carbon under Shock Loading

WU Cheng, Gupta Y M

2002, 16(1): 34-41 . doi: 10.11858/gywlxb.2002.01.006

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Abstract:
The shock impact experiments of vitreous carbon under uniaxial strain were conducted on a keyed light-gas gun. With two X-cut shorted quartz gauges assembled on impactor and target the two stress histories were recorded and used to analyze the dynamic response of vitreous carbon up to 3.7 GPa. Based on the theory of characteristic line and Riemann integrate method, the more reasonable and precise stress histories in shocked state have been corrected, the constitute model of vitreous carbon under shock loading is obtained and used in the COPS simulation code. The simulated stress profiles are agree with the experimental ones quite well.

Electrical Property and Equations of State in Carbon Nanotubes at High Pressure

BAO Zhong-Xing, CHENG Hui-Ming, BAI Shuo, LI Feng, HOU Peng-Xiang, LIU Cui-Xia

2002, 16(1): 42-45 . doi: 10.11858/gywlxb.2002.01.007

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Abstract:
The resistance-pressure relationship for multi-wall carbon nanotubes at room temperature and up to 23 GPa was studied in a diamond anvil cell using resistance measurement. The experimental results show that the resistance decreases sharply with pressure in 1.5～4.6 GPa, and exhibits a maximum value at about 5.7 GPa, which concerns the changes of the structure, shape and inter layer distance of carbon nanotubes. In the present work, the p-V relationships for multi-wall carbon nanotubes at room temperature at pressures up to 4.5 GPa were first studied using the piston-cylinder type measurement device for the p-V relationship. Its equations of state at first and seventh time compression were given.

Numerical Simulation of Shock Temperature of Mixtures during Shock Loading

LIN Hua-Ling, HUANG Feng-Lei, YU Wan-Rui

2002, 16(1): 46-56 . doi: 10.11858/gywlxb.2002.01.008

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Abstract:
Several numerical methods to estimate temperature of mixtures during shock loading are introduced. Numerical results of shock compression behaviors of mixtures simulated using a 3D hydrodynamic finite element code are in good agreement with these from Hugoniot equations. On analyzing the effect of heat conduction, the shock temperature of the mixture and the shock Hugoniot curve are obtained.

One-Dimensional Simulations of Single Temperature Radiative Magnetic Field Dynamics for Liner Implosion Experiments

WANG Gang-Hua, HU Xi-Jing

2002, 16(1): 57-60 . doi: 10.11858/gywlxb.2002.01.009

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Abstract:
A 1D single temperature radiative MHD (Magnetic Hydro-dynamics) model and the related results of single wire implosions have been described in this article. The contribution of black body radiation to the energy flux was considered. The drive current was sine wave with the peaks at 10 kA, 30 kA, 50 kA and 400 kA, respectively.

Theoretical Hugoniot Curves of Liquid Deuterium

CHEN Qi-Feng, CAI Ling-Cang, CHEN Dong-Quan, JING Fu-Qian

2002, 16(1): 61-64 . doi: 10.11858/gywlxb.2002.01.010

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Abstract:
Based on liquid variation perturbation theory with quantum mechanics correction, the effective exp-6 potential is adopted to determine single- and double-shock Hugoniot curve of liquid deuterium in the pressure range up to 80 GPa. Estimated shock pressure is in agreement with experiment data. However predicted shock temperature is higher than experimental data.

Temperature Field Model for Explosive Welded Multilayer Amorphous Foils

YAN Hong-Hao, LI Xiao-Jie, XI Jin-Yi, DONG Shou-Hua

2002, 16(1): 65-69 . doi: 10.11858/gywlxb.2002.01.011

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Abstract:
Based on the analysis of heat generation and conduction process during explosive welding of multilayer amorphous foils, square wave model for the temperature field across interfaces between foils was suggested. The model was used to explain why amorphous state is not changed across interfaces after explosive welding, and the results accord is in good agreement with the fact.

Theoretical Calculated Shock-Compression Properties for Liquid Helium

MENG Chuan-Min, JIAO Rong-Zhen, SHI Shang-Chun, DONG Shi, SUN Yue, YANG Xiang-Dong, JING Fu-Qian

2002, 16(1): 70-74 . doi: 10.11858/gywlxb.2002.01.012

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Abstract:
For liquid helium, the modified WCA liquid perturbation theory was used to calculate Hugoniot curve using EXP-6 reference potential. The theory is generalized to include quantum effects by adding the first term of Wigner-Kirkwood expansion. The theoretical calculated pH and TH are in good agreement with experimental data up to 56 GPa where liquid helium is compressed to densities up to five times greater than the normal and heated to temperature up to 21 000 K. Parameters of EXP-6 potential are chosen as =12.7, r*=0.296 73 nm, /k=10.8 K respectively.

Shear Fracture of HR-2 Steel Tube under Shock Loading

TANG Tie-Gang, HU Hai-Bo, WANG De-Sheng, HU Ba-Yi, LI Qing-Zhong, ZHANG Cong-Yu

2002, 16(1): 75-79 . doi: 10.11858/gywlxb.2002.01.013

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Abstract:
The shear fracture phenomena of HR-2 steel tube under shock loading were studied. The results of X-flash photography show that shear fracture occurred in the HR-2 steel tube during shock loading. The changes of microstructure at different radius were observed in the recovered samples. Also, adiabatic shear bands on the tip of microcracks and microvoids within the adiabatic shear bands appear.

2002 Vol. 16, No. 1

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