高压物理学报

High-Pressure Phase Transition and Constant-Temperature Compression of Caiclum Titanate Ore

XIONG Da-He, B. C. Ming, M. H. Manghnani

1988, 2(1): 1-9 . doi: 10.11858/gywlxb.1988.01.001

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Abstract:
By using a diamond anvil cell with ruby fluorescence pressure calibration system and aYAG laser, polyerystalline GaTiO3 (perovskite) was investigated under static pressure up to 38 GPa and temperature up to 1 000 ℃. In situ X-ray diffration data reveals that at room temperature, orthorhombic GaTiO3(Ⅰ) transforms into hexagonal GaTiO3(Ⅱ) at 10 GPa with a volume change of 1.6%; at 1 000 ℃ and non-hydrostatic environment, orthorhombic GaTiO3(Ⅰ) transforms into tetragonal GaTiO3(Ⅲ) at 8.5 GPa and then into hexagonal GaTiO3(Ⅱ') at 15 GPa with volume changes of 0% and 1.6% respectively. All these three high pressure polymorphs occured in the study are nonquenchable. The isothermal compression of orthorhombic GaTiO3 was performed under standard hydrostatic environment with pressures not greater than 10.4 GPa. By assuming K0'=5.6, which was obtained on SrTiO3 perovskite ultrasonically, the value of bulk modulus K0 was calculated to be (2107)GPa by using Birch-Murnaghan equation.

Some Investigations on the High Pressure Synthesis of Niobium Trisulfide and XPS Analysis

SHEN Zhu-Tong, DAI Shou-Yu, CHEN Li-Quan, CHI Yong-Qian

1988, 2(1): 10-16 . doi: 10.11858/gywlxb.1988.01.002

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Abstract:
In this paper, we will report the new result of some investigations on the high pressure synthesis of NbS3 and its phase transition including some characteristics of its crystal structure, electron state and the peierls transition occured in its with special crystal structure.

Shock Compression Measurement for 2169 Steel at 2 TPa

JIN Xiao-Gang, LIU Quan-Zhong, YANG Mu-Song, QIN Dao-Kai, XIAO Xue-Zheng

1988, 2(1): 17-21 . doi: 10.11858/gywlxb.1988.01.003

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Abstract:
A shock wave generated by an underground explosion was used to perform the shock compression measurement for the 2169 steel sample. The measurement is based on impedance-matching method and the iron material is used for standard. An array of 47 electrical pins was used to determine the shock velocities in the standard in the 2169 steel sample, and the shape of the shock front. The measured shock compression parameters are as follows: us (shock velocity)=22.12 km/s, up (particle velocity)=13.39 km/s, p (shock pressure)=2.31 TPa and (shock compression ratio)=2.53. The measured results are in agreement with the extrapolation value of the previous experiment performed using explosive system at lower pressures.

An Isothermal Equation of State of Solid (Ⅳ)

XU Ji-An

1988, 2(1): 22-33 . doi: 10.11858/gywlxb.1988.01.004

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Abstract:
A general property of the invariance under pressure translation of the isothermal equation of state of solid from Ref.1 is given, then, a model of an ideal solid and an absolute pressure are discussed. Wealso give two kinds of formats which can be used in the mathematical approach in the equation of state of real materials.

The Elastic Behaviour of the Amorphouse Carbon under High Pressure

WANG Ji-Fang, WANG Ru-Ju, HE Shou-An

1988, 2(1): 34-41 . doi: 10.11858/gywlxb.1988.01.005

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Abstract:
By using the pules echo ultrasonic technique with 10 MHz, the ultrasonic velocities of the amorphous carbon and their pressure dependence have been measured in the pressure up to 1 GPa. We have calculated its second-, third- and combinations of forth-order elastic constants, and have researched its Gruneisen constant, Debye temperature, specific heat and state change under high pressure.

A Practical EOS of Elastic-Plastic Fluid (Ⅰ)

CHEN Xiang-Tao, LI Mao-Sheng, CHEN Dong-Quan

1988, 2(1): 42-50 . doi: 10.11858/gywlxb.1988.01.006

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Abstract:
This paper presents a convenient and practical EOS of elastic-plastic fluid, based on the Mie-Gruneisen equation, using Hugoniot pressure and energy as the reference with density 0. In addition, the relation of Gruneisen coefficient (p)for 0 is also presented. The practicality and reliability of these formulas have been verified in actual works.

Equation of State and High Pressure Phase Transition of CdTe

HU Jing-Zhu, TANG Ru-Ming

1988, 2(1): 51-57 . doi: 10.11858/gywlxb.1988.01.007

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Abstract:
The equation of state and high pressure phase transition of CdTe were studied by DAC X-ray diffraction technique at room temperature up to 39.2 GPa. The phase transition sequence is: from zinc blede phase to NaCl phase at (3.30.1)GPa with 15.8%volume change, from NaCl phase at to -Sn phase at (10.30.2)GPa without volume change and from -Snphase to orthorhombic phase at (12.20.2)GPa without volume change too. The data of compression of CdTe were fitted to bridgeman state equation of Murnaghan state equation. The bulk modulus and its pressure derivative of each phase was compared with other experimental and theoretical results.

A Study on the Formation and the Stability of Al6Mn Quasicrystal under High Static Pressure

ZHANG Qiang, SU Wen-Hui

1988, 2(1): 58-66 . doi: 10.11858/gywlxb.1988.01.008

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Abstract:
In this paper, a new method of quenching at fuse state (1 300 ℃) under high static pressure (4.5 GPa) hase been set up to prepare the quasicrystal icosahedral phase of the Al6Mn alloy, the crystallization temperature of which is close to the one of rapid cooling ribbon sample, and the cooling rate during the quenching is of about 102 ℃/s. A new intermediate metastable phase (a T-phase-like) occures during the crystallization process of Ⅰ-phase under high static pressure (2.5 GPa) for the rapid cooling ribbon of Al6Mn. The high static pressure increases its crystallization temperature and enhances the stability of the intermediate metastable phase.

A Study on High-Pressure Syntheses and Properties of La1-xSrxCoO3 Series

ZHANG Jin-Long, ZHOU Jian-Shi, SU Wen-Hui

1988, 2(1): 67-72 . doi: 10.11858/gywlxb.1988.01.009

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Abstract:
By using the high-pressure method for the first time, the series of compounds La1-xSrxCoO3 (x=0.0, 0.2, 0.3, 0.4, 0.6, 0.8 and 1.0) have been synthesized at the condition of 2.6 GPa/1 050 ℃/40 min. After the study of their structure transformation, distortions and oxygen vacancies and the discussion of Valence changes, the conclusion that high pressure decreases the oxygen vacancy and results in some Co ions in low valence state hase been obtained. The effects of the factors mentioned aboved on the properties of electric conductivity and catalysis have also been discussed.

Molecular Dynamic Investigation of Shock Waves in the Solid

YU Wan-Rui, LIU Ge-San

1988, 2(1): 73-78 . doi: 10.11858/gywlxb.1988.01.010

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Abstract:
Molecular dynamic techniques were used to study the changes of the temperature, pressure, particle velocity on fcc crystals acted by shock wave. The results were ompared with macroscopic law. Fincham's calculation form was adopted in this paper. Morse potential was taken as the interaction potential between two atoms and its parameters were obtained approximately by the nearest neighbor interaction.

An One-Dimensional Characteristic Method for Evaluating the Enhancement and Decay of Shock Waves Driven by Laser Pulses

MA Min-Xun, GU Yuan, WANG Yong-Gang

1988, 2(1): 79-84 . doi: 10.11858/gywlxb.1988.01.011

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Abstract:
A simple method for estimating the enhancement and decay of laser driven shock waves is prepared in this paper. Using this method, we estimated the enhancement and decay of shock waves in aluminum foils irradiated by laser pulses with trapezoidal and Gaussian shaped. The results were compared with other references.

Influence of Diamond Particle-Size on Wearability of High Pressure Synthetic Polycrystal Diamond

Lü Zhi, DAI Yu-Zhi

1988, 2(1): 85-88 . doi: 10.11858/gywlxb.1988.01.012

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Abstract:
By studying the influence of diamond particle-size on the wearing resistance of polycrystal diamond (PCD) experimently. It was found that the variation of diamond particle-size has strong influence on the wearing resistance of PCD. On the basis of the observation and analysis of the microstructures in PCD, it was concluded that the increase of the wearability of the PCD synthesized from fine particle-size diamond results from its increase of dense-in-itself.

Experimental Investigation on Densification of Sintered Diamond Polycrystals with Inclusions

WANG De-Xin, LIU Pei-Luan, JIAO Qing-Yu, XUE Yong-Jin, YANG Guo-Qing

1988, 2(1): 89-91 . doi: 10.11858/gywlxb.1988.01.013

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Abstract:
Experimental results showed that the diamond polycrystals synthesized with titaniumsilicon-boron binder are denser than that with nickelsilicon-boron binder, and that the diamond polycrystals using fine diamond grains are denser than that using coarse diamond grains. Furthermore, diamond polycrystals synthesized with titaniumsilicon-boron using fine diamond grains have a higher wearing capacity.

An Empirical Expression of Elastic Sound Speed of Materials at High Pressures

WANG Gui-Chao

1988, 2(1): 92-95 . doi: 10.11858/gywlxb.1988.01.014

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Abstract:
After treating analyticaly the measured elastic sound speed c of seven materials, including aluminum, iron, copper and so on, at high pressures, it is shown that the change of the elastic sound speed with pressures may be described as ln c=A0+A1ln p+A2ln2p , here, A0, A1, A2, are meterial constants, p is the pressure. The relative error between the fitting data and the measured data is less than 5%.

1988 Vol. 2, No. 1

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