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The uniaxial compressive fracture behavior of a Hf44.5Cu27Ni13.5Ti5Al10 bulk metallic glass (BMG) was investigated at different strain rates (10−4∼103 s−1) by an INSTRON-5569 testing machine and Split Hopkinson Pressure Bar. The results show that the Hf44.5Cu27Ni13.5Ti5Al10 bulk metallic glass isn't sensitive to strain rate under the quasi-static compression condition. The fracture strength is 2400 MPa. The fracture strength is 2840 MPa under the dynamic compression. The dimple structure and periodical corrugation formed at the fracture surface were observed. The fracture mechanism attributed to ductile fracture in the range of micro-scale. In addition, interaction of elastic waves and the dynamic crack front plays an important role during the formation of periodic corrugations. The higher fracture stress and adiabatic temperature are caused by the higher dynamic compressive strain rate. Phase separation was formed by segregation and diffusion at the interface during compression and affected the formation of shear cracks/bands.

The research on morphology of mineral crystals in China includes classical goniometry of 100 minerals such as hsianghualite, orthobrannerite, jamesonite and bertrandite and surface microtopography of 20 minerals such as wolframite and diamond, among which 5 new minerals and 34 uranium minerals were discovered and measured by Chinese mineralogists. These have enriched mineralogy and crystal morphology and strengthened the study of information of morphological genesis.

Objective: To investigate the effects of hibernation drugs on early wound sepsis in severely scalded rats. Methods: Sprague-Dawley rats inflicted 30% TBSA deep thickness were randomly divided into A (immediate resuscitation) and B (immediate resuscitation and lytic cocktail). After infusion of 108 CFU/ml Pseudomonas aeruginosa in the wound on third postburn day, survival was compared between two groups. Local tissue samples and plasma were collected and the plasma level of IL-2 mRNA, IL-4 mRNA, IL-10 mRNA, and IFN-γ mRNA were assayed by fluorescence PCR. Results: Compared with Group A, host survival significantly increased (0.663 ± 0.026, P

The structure or short-range order of clusters in undercooled metallic melts is influenced, to some extent, by the interfacial free energy between the cluster and the melt. Analyses of the effects of interfacial energy on the cluster structure based on the Gibbs equation show a possibility that atoms in the clusters tend to be packed more loosely with the increasing cluster size (or the undercooling). Nucleation may occur, following these analyses, when clusters reach a definite size and atoms in the clusters relax to some extent to form the crystal structure. Indirect support to this viewpoint is provided by the present results of cluster-induced nucleation experiments on undercooled Ge73.7Ni26.3 alloy melts.

Droplets of Zr41Ti14Cu12.5Ni10Be22.5 glass-forming alloy with different sizes are solidified in a drop tube containerless process. The glass transition temperature Tg of Zr41Ti14Cu12.5Ni10Be22.5 glassy spheres solidified with different cooling rates is investigated by using a differential scanning calorimeter. It was found that all the amorphous spheres show an increase of Tg with the heating rate. The glassy spheres have a unique value for the glass transition activation energy Eg = 435.50 kJ/mol, which is independent of cooling rate q. The insensitivity of Tg to q is interpreted by an extension of the free volume model for flow.

Ti-based bulk metallic glasses (Ti4oZr25Cu9Ni8Be18)100-xNbx with x = 0 to 5at.% are prepared by copper-mold casting. The glass formation ability is almost unchanged by addition of Nb. The compression plasticity is, however, apparently changed, from 3% at x = 0 to 13% at x = 3, about 330% increases at the strain rate of 1 × 10−4s−1. The increment of the plasticity can be attributed to the segregation of Nb in the area of shear bands during the compression processing. An effective way to increase the plasticity of Ti-based bulk metallic glasses is thus proposed.

Cylinder-shaped Cu80 Ni20 alloy melt is undercooled and solidified by the combination of the electromagnetic levitation technique and the flux treatment method. Nearly constant temperature gradient of 8-10K/cm is realized for the cylindrical melts with different undercooling levels at the bottom ends. The experimental results reveal that with the increase of the undercooling of the melts from 35 to 220K, the microstructures undergo transition from coarse dendrites to granular grains, unidirectional dendrites, and finally to equiaxed grains.

By employing the first-principles pseudopotential plane-wave method, the physical properties of zincblende ZnO are investigated in comparison with those of the common wurtzite structure. Zincblende ZnO is predicted to be a direct gap semiconductor. Compared to the wurtzite structure, the zincblende ZnO is characterized by smaller bandgap and pressure coefficient, larger electron effective mass, increasing static dielectric constants and more covalent bonding. Furthermore, the optical properties including dielectric function and energy loss function of zincblende ZnO were obtained and analysed with some features. These aspects reveal promising applications of zincblende ZnO in optoelectronic devices.

The specific heats of two nanocrystalline iron samples with different structures have been measured in the temperature range from 2 to 26 K. Experimental results show that the specific heat of nanocrystalline iron samples exhibits abnormal characteristic compared with that of standard bulk iron. The contributions of quantum size effect, surface mode and Einstein mode have been observed in the measurement. Through analyses, it is discovered that the relative density and particle size have a great influence on specific heat of nanocrystalline iron at low temperature.

The compression of Zr44.4Nb7Cu13.5Ni10.8Be24.3 bulk metallic glass (BMG) is investigated at room temperature up to 39 GPa using {in situ} high-pressure energy dispersive x-ray diffraction with a synchrotron radiation source. The equation of state of the BMG is obtained by the calculation of the radial distribution function. Pressure-induced structural relaxation is exhibited. It is found that below about 6 GPa, the existence of excess free volume contributes to the rapid structural relaxation, which gives rise to rapid volumetric change, and the structural relaxation results in structural stiffness under higher pressure.

The Pd77.5 Au6Si16.5 alloy was studied by drop-tube processing. Palladium solid-solution phase was found in smaller droplets (diameter D

The solidification and glass forming ability of Zr41Ti14Cu12.5Ni10Be22.5 bulk glassy forming alloy is investigated by Bridgman unidirectional solidification at different growth velocities under different gravity field orientations. Large differences in glass formation, undercooling and crystallization morphology on different solidification conditions have been found and discussed from the point of view of gravity induced convection. The results are useful for understanding the nucleation and growth in the melt and glass formation mechanism in the alloy.

The high-pressure behaviour of the superconductor MgB2with a hexagonal structure has been investigated by thein situsynchrotron radiation x-ray diffraction method under pressures up to 42.2 GPa in a diamond anvil cell. An abrupt decrease of about 7% in the unit cell volume of this material occurs in the pressure range of 26.3-30.2 GPa. A split of the Raman spectrum was also observed. The jump of the compression curve and Raman spectrum are ascribed to an isostructural transition in MgB2at a pressure of 30.2 GPa.

The Pd39Ni10Cu30P21 bulk metallic glass is isothermally relaxed under various pressures. The degree of the structural relaxation is evaluated in terms of the enthalpy recovery behaviours involved in the irreversible glass transition processes by using a temperature-modulated differential scanning calorimetry technique. A roughly Linear increase of the recovery enthalpy is observed within the experimental pressure range fi-om 2.67 to 4.45 GPa, which reflects the release of the frozen-in enthalpy in the as-quenched glass with increasing relaxation pressure. The pressure dependence of the timescale of the enthalpy recovery processes is also exhibited.

Elastic properties of platinum nitride (PtN) are studied by first-principles calculations with the fully relativistic full potential linearized augmented plane-wave (LAPW) method, the plane-wave ultrasoft pseudopotential (PW-PP) and the projector-augmented wave (PAW) methods. The results reveal that: (1) the scalar relativistic scheme is sufficient to treat the valence electronic structure, i.e. the spin-orbit effect has little effect on the bulk modulus value of platinum nitride; (2) the all-electron full potential method is no more accurate than the pseudopotential and PAW-based methods when calculating the lattice constant and bulk modulus properties of the platinum nitride; (3) platinum nitride in zinc-blende structure is unstable and its crystal structure is still an open problem.

High speed impact experiments of rectangular plate-shaped Zr41Ti14Cu12.5Ni10Be22.5 bulk metallic glass (BMG) were performed using a two-stage light gas gun. Under spherical shock waves with impact velocities ranging from 0.503 km/s to 4.917 km/s, obvious traces of laminated spallation at the back (free) surface and melting (liquid droplets) at the impact point were observed. The angles about 0?, 17?, 36?, and 90? to the shocking direction were shown in the internal samples because of the interaction between the compressive shock waves and the rarefaction waves. The compressive normal stress was found to induce the consequent temperature rise in the core of the shear band.

The phase transformation activation energy of the Cu61.13Zn33.94Al 4.93 alloys, which were treated at 4 GPa and 700 °C for 15 minutes, was calculated by means of differential scanning calorimetry curves obtained at various heating and cooling rates. Then, the effects of high-pressure heat treatments on the solid-state phase transformation and the microstructures of Cu61.13Zn33.94Al4.93 alloys were investigated. The results show that high-pressure heat treatments can refine the grains and can change the preferred orientation from (111) to (200) of α phase. Compared with the as-cast alloy, the sample with high-pressure heat treatment has finer grains, lower β' → β and β → β' transformation temperature and activation energy. Furthermore, we found that high cooling rate favours the formation of fine needle-like α phase in the range of 5–20 °C/min.

Effects of high pressure (6 GPa) on the solid state phase transformation kinetic parameters of aluminum bronze during the cooling process are investigated, based on the measurement and calculation of its solid state phase transformation temperature, duration and activation energy and the observation of its microstructures. The results show that high pressure treatment can reduce the solid phase transformation temperature and activation energy in the cooling process and can shorten the phase transformation duration, which is favorable when forming fine-grained aluminum bronze.

Zr41Ti14Cu12.5Ni10Be22.5 bulk metallic glasses (BMG) are annealed at a temperature of 603 K under ambient and high pressures in the range of 3−6 GPa. The effect of high pressure annealing on the nanocrystallization process of compressed specimens is investigated by x-ray diffraction, differential scanning calorimetry and transmission electron microscopy. Experimental results show that the grain size of the crystalline phase decreases with the increasing pressure. For the Zr41Ti14Cu12.5Ni10Be22.5 BMG annealing at 603 K in the pressure range of 0−6 GPa, the activation energy 159.68 kJ/mol and the activation volume ΔV* = 0.94 cm3/mol are determined. The mechanism for the effects of the high pressure on the nanocrystallization process of the BMG is discussed.

The effect of yttrium addition on glass formation of a ZrCuAlSi alloy is investigated. The maximum diameter 8mm of the glassy rods for (Zr46.3Cu43.3Al8.9Si1.5)100−xYx alloy with x = 2.5 is obtained by copper mould casting. Apparent enhancement of the glass formation ability is found with addition of yttrium, mainly due to the purification of the alloy melt and the suppression of formation of the primary phases by yttrium.

The glass transition and crystallization behavior of Zr46.75Ti8.25Cu7.5Ni10Be27.5 bulk amorphous alloy are investigated by X-ray diffraction and differential scanning calorimetry under high temperature and high pressure. The results show that the free volume and enthalpy and crystallization activation energy decrease with increasing pressure.

Grain fragmentation and property modification of nanocrystalline ZnO under high pressure were studied on CS-1B 6×8000 kN cubic high pressure apparatus. Grain size and microstructure of the samples have been characterized by X-ray diffraction and field emission scanning electron microscopy. The results show that the significant grain fragmentation phenomenon occurs inside the crystallites. Experimental results on hardness and the current-voltage characteristics indicate that micro-hardness of the samples after high pressure is 2.3 times that of the samples sintered at atmospheric pressure and the nonlinear current-voltage characteristics is obviously better than that of the latter.

Based on the generalized gradient approximation, we have investigated the phase transition of 3C-SiC from ZB to NaCl structure using first-principles method, and obtained the accurate symmetry Imm2 (previously regarded as lower symmetry Cmm2 and Pmm2) of the intermediate phase. The relative activation enthalpy 0.647eV is close to the result of Catti. The obtained transition pressure 69GPa is lower than the experimental value of 100GPa which may be attributed to the hysteresis of the phase transition. Meanwhile, the energy bands for ZB- and NaCl-SiC were also calculated and discussed, the results suggest that the phase transition of 3C-SiC is accompanied by an electronic transition from semiconducting to metallic character besides the structure reconstruction, which may be useful for the accurate determination of the transition pressure.

ZnO nano-bulk materials with high density and low brittleness is prepared on CS-1B 6×8000kN cubic high pressure apparatus. Grain sizes and microstructures of the samples have been characterized by X-ray diffraction and field emission scanning electron microscopy. The Raman spectra of polar semiconductor ZnO are studied by Raman spectrophotometer in the range of 50—500cm-1. No obvious size confinement effect is found in the polar semiconductor oxide.

Nano_scale ZnO green disks are prepared by continuous compaction process. Relation between green density, sintering time, densification temperature and compaction method is examined. Microstructure of the samples is characterized by an XL30S_FEG field esmission scanning electron microscopy. Hardness of the ZnO nano_bulk is measured as a function of sintering temperature. The results show that gree n density is increased by 56%, sintering time is decreased by 3h and densifica tion temperature is decreased by 200℃ after the continuous compaction process. Distributions of density and grain size within the sintered body are homogeneous through examination of the XL30S_FEG field esmission scanning electron microsco py. Hardness values imply that the relation between micro_hardness and sintering temperature is not monotonic, but first increasing then decreasing with increas ing sintering temperature in the ZnO nano_bulk. The grain size at the inflexion point is about 50—60nm.

Influence of pressure on solidification microstructure of FeSi2 alloy is investigated. Different from the eutectic structure of the sample solidified at normal pressure, the microstructure of the sample solidified at high pressure is composed of dendritic primary phase and anomalous eutectic. The significant change in microstructure results from the change of phase diagram and solute atom diffusion induced by high pressure. By introducing the pressure parameter, the constitution undercooling criterion is attained. Formation mechanism of dendritic primary phase under high pressure is analysed according to the constitution criterion.

Diffusion of Co in Zr＿46.75Ti＿8.25Cu＿7.5Ni＿10Be＿27.5 bulk metallic glass under high pressure is investigated in supercooled liquid regio n by ion implantation combined with secondary ion mass spectroscopy.Before impla ntation of Co atoms,the amorphous samples were annealed and relaxed in supercool ed liquid region.Diffusion coefficients of Co at 603K in the relaxed samples are found to increase with increasing pressure.And the activation volume for diffus ion is obtained to be -1.236Ω,where Ω is the mean atomic volume of the alloy.The result shows that diffusion of Co in this case is in an interstitial way.

Zr41Ti14 Cu-12.5 Ni-10 Be-22.5, bulk amorphous alloy rods with an aspect ratio of 25 : I were prepared. Thermal expansion coefficient of the alloy was measured. The effects of structural relaxation on hardness and thermal expansion coefficient of the amorphous alloy are studied. A suitable temperature range for super - plastic deformation of the bulk metallic glass is determined by thermal expansion experiments.

An alternative approach to bulk glass formation is to freeze the melts under pressure. If long-range atom diffusion-controlled growth can be suppressed by the pressure, then the crystallization could not occur even if copious nucleation centres existed in the melt. Therefore, the melt can be cooled below the glass transition, temperature T g , and vitrification takes place. In the present work the Pd 40 Ni 40 P 20 alloy was chosen because it is an easy glass former (with reduced glass transition temperature T rg =0.67) and for it the bulk glass has been formed by thermal treatment and fluxing except under high pressure

A rapid drop of pressure applied to a melt whose crystallization point is a decreasing function of the pressure may,if the temperature,the initial pressure and the final pressure are appropriately chosen,be equivalent to a rapid thermal quenching.In particular,it may lead to the formation of metastable crystalline or glassy-phase bulk materials.The method might be useful to simulate adiabatic decompressions subsequent to shocks,such as meteorite impacts.The relation between the corresponding cooling rate(Vc) obtained by rapid decompression and the rate of pressure release(Vp) is first given by Vc=KVp,where K is the drop rate of melting point with pressure.This method is evaluated by using Al-Ge system.Our experimental results indicate that quenching with rapid decompression is an effective method for generating corresponding high cooling rate of more than 105K·s-1.

A structural transition from rhombohedral to cubic phase occurred in the lightly doped La1-xSrxMnO3 under high temperature and high pressure. The samples changed from an insulated (polaron ordering) state to metallic state after the phase transition. At the same time, the long-range ferromagnetic ordering of the spins of localized Mn ions collapsed into the spin glass state with only short-range ordering when the temperature decreased. The change of properties was due to the variation of Mn—O—Mn bond angle and Mn—O bond length during the structural transition.

The microstructural transformations of carbon nanotubes under high-pressure annealing have been studied by high resolution transmission electron microscopy. It is found that under 5.5GPa the microstructure of nanotubes has obviously changed at an annealing temperature of 770℃, while onion-like and ribbon-like structures formed at 950℃. The transformation from carbon nanotubes into quasi-spherical onion occurs in several steps, first the shells of nanotubes collapse, then spheres form and finally onion-like structures appear. The effects of high pressure and annealing temperature on microstructural changes are discussed.

This paper studies the phase morphologies of glass-forming Zr65Cu17.5Ni10Al7.5 alloy during unidirectional solidification, as well as the gravity influence on them. The direction of the microstructure became worse when the moving speed of the furnace exceeded a critical value. This critical speed was about 5mm/min for Zr65Cu17.5Ni10Al7.5 alloy in the present experiments. Different relationship between the direction of the movement of the solid-liquid interface and the gravity field led to different states of buoyancy convection, and finally different phase morphologies were obtained. When the movement direction was the same as the gravity vector, the primary phase was less and finer without an evident transition region in front of the interface. However, when the two directions were opposite to each other, more and coarser primary phase was obtained with an evident transition region appearing in front of the interface.

Solid state amorphization reaction process in Ni/amorphous Si multilayers has been quanlitatively studied by using in situ X-ray diffraction. An amorphous formation and growth model is suggested for elucidating the solid state reaction in the Ni/amorphous Si multilayers. Thermodynamic and kinetic interpretations for the amorphization reaction at grain boundaries in Ni sublayers are presented.

This paper studies the difference of solute distribution in microstructure of Pd40Ni40P20 alloy solidified on board a Chinese Retrievable Satellite and on the ground.Compared with those in normal gravity condition(1g),it was found that P content was lower but Pd content was higher in the primary phase,however in the eutectic region P content increased but Pd content decreased in microgravity condition(μg).By evaluating the mass transport coefficients in both cases it can be concluded that the difference in solute distribution both in 1g and μｇ conditions was due to the existence of buoyancy convection in the ground-based experiments.

The nucleation and undercooling of Al4Mn alloy have been investigated with 1.2 meter long drop tube. Melt droplets were solidified in vacuum and various sizes of droplets were collected at the bottom of the tube. Besides orthorhombic Al6Mn and β-Mn phases, there are two approximants of the decagonal quasicrystal, one approximant of the icosahedral quasicrystal, and decagonal domains, observed in the droplets. However, the amount of each phase is different in samples of various sizes due to the different cooling rates and undercooling. The relationship between the phase composition and the sample size was discussed on the basis of the classical nucleation and growth theories.

Solid state reaction interdiffusion of Fe-Ti multilayer modulated films was investigated by means of dynamic in situ X-ray diffraction. With this method, the measurement of the X-ray modulation peak intensity was relatively accurate and the shift in X-ray modulation peak position was also observed. The interdiffusion coefficients of Fe-Ti modulated films were calculated at different temperatures. Plots of the interdiffusion coefficients versus time at different temperatures were given. According to the variation rate of D vs. τ, the activation enrrgy Qy relative to viscosity relaxation was calculated to be 8.3±0.2 kcal/mol.

he diffusion mechanism of the Ni in amorphous Si was studied by in situ X-ray diffraction technique in amorphous Ni/Si multilayer. The temperature dependent diffusivity of Ni in amorphous Si was obtained in the form of Arrheneius relationship. A trap-retarded interstitial diffusion mechanism is suggested to explain the diffusion process of Ni in amorphous Si.

The interfacial solid state reaction was studied in the Ni/a-Si multilayer. The thermody-namic and kinetic aspects of the solid state amorphization was explained according to the calculated metastable free energy diagram. A kinetic reaction model for the solid state amorphization reaction of Ni/a-Si multilayers is developed.

The effects of quasi-hydrostatic pressure treatments on the Bi-system superconductors were investigated The cold-pressing treatments seriously weakened the inter-granular weaklinks and induced a large number of intragranular defects, resulting in the deterioration of the suprcon-ducting properties. The targe increase in the bulk density and the orientation of the superconducting grains were also observed in the cold-pressed samples. These drastic changes of superconductivity were mainly due to the shear stress under quasi-hydrostatic pressure. The post annealing treatments greatly enhanced the weaklinks and caused the partial recovery and the agglomeration of some defects. By coldpressing-annealing method, Jc (77 K, zero field) was raised to about 1600A/cm2. The pressure dependence of Tc under hydrostatic pressure was also investigated and dTc/dp was found to be 1.4K/GPa.

The Pd77.5Au6Si16.5 alloy was studied by means of a drop tube processing. Pd solid solution phase was found in smaller droplets (diameter D3Si was observed. The difference of free energy between underco-oled liquid and solid state, the activation energy for the formation of postcritical nuclei, tie nucleation rate and the speed of crystal growth were calculated as a function of temperature for Pd solid solution and PdsSi phases, these calculations led to time-temperature-transforma-tion curves which may be used to describe the experimental findings oa the kinetics of solidification of this alloy.

In this paper, we report the amorphization observed in Fe-Ti and Fe-Si systems through a solid state reaction at low temperatures, and confirm the formation of amorphous Ni-Ti alloy after reaction. This new amorphization processes can be considered as the result from competing amorphous phase with crystalline phase in kinetics. A kinetical criterion for forming amorphous phase by solid state reaction is discussed in detail.

This paper reports the result of undercooling experiment of Pd-Ni-P alloy. Bulk metallic glass of Pd41)Ni40P19 has been formed by thermal treatment with B2O3 as fluxing. The effect of cooling rate on the undercooling behavior was studied. The surface heterogeneous nuclea-tion was reduced by embeding the sample into B2O3 melt. Thus the cooling rate used to form the glass was as low as 1 K/s at the glass transition temperature of 590 K. The temperature-time-transformation curves were calculated by using the classical homogeneous and heterogeneous nucleation theory. The critical cooling rates for the glass formation were calculated. The resuits are discussed in some detail.

The solid state reaction of Ni50Ti50 multilayer under high pressure was carried out to investigate the effect of pressure on the amorphization process. Under the pressure of 20kbars amorphization reaction could not occur at 250° C while amorphous phase formed by isothermal annealing at same temperature in vacuum as well as lower pressure. It is suggested that the effect of pressure on diffusion played a predominant role, and Ni atom should diffuse into Ti layers with vacancy mechanism rather than interstitial one.

The structural transition process of the superconducting phase in Bi1-xPbxSrCaCu2Oy (x=0, 0.2) samples has been investigated at temperatures ranging from -190°C to 800°C by means of electron diffraction. Two structural phase transitions have been found at the temperatures about 310°C and 490°C respectively for the BiSr CaCu2Oy sample, and about 310°C and 470°C for the Bi0.8Pb0.2 SrCaCu2Oy sample. After these transitions a new structural phase forms.

The A15 Nb3Si with a smaller lattice parameter (α=0.5093nm) has been synthesized from the amorphous Nb77Si23 alloy under high pressure by using Bridgman anvils apparatus. Superconductivity measurements showed that the A15 phase produced from Nb77Si23 has the highest TC (19.1K) among all that can be obtained from Nb-Si alloys.

Superconducting critical transition with onset at 123K and zero resistance at 101K are obtained by hot pressing in the Bi-Pb-Sr-Ca-Cu-O system. A.C.χ measurements show that there are 85K superconducting phase except for 110K superconducting phase. This sample has been investigated by X-ray powder diffraction and SEM observation, the X-ray powder diffraction patterns of two main superconducting phase can be indexed in the forms of orthorhombic cells with lattice parameters a=5.420 A , b=5.447 A , c=30.845 A and a=5.420 A , b=5.447 A , c=36.884 A respectively. As expecting SEM experiment shows that a lower porosity was obtained in the hot pressed sample.

The solid-state reaction technique has been used to form the amorphous Ni50Ti50 film. The alternative layers were prepared by an electron beam evaporating apparatus. The amorphization was determined by means of x-ray diffraction and confirmed by DSC experiments.