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| 1 | Peritectic solidification under high undercooling conditions显示文摘The solidification characteristics of highly undercooled Cu-7.77% Co peritectic alloy has been examined by glass fluxing technique. The obtained undercoolings vary from 93 to 203 K(0.14 T_L). It is found that the a(Co) phase always nucleates and grows preferentially, which is followed by peritectic transformation. This means that the peritectic phase cannot form directly, even though the alloy melt is undercooled to a temperature far below its peritectic point. The maximum recalescence temperature measured experimentally decreases as undercooling increases, which is lower than the thermodynamic calculation result owing to the actual non-adiabatic nature of recalescence process. The dendritic fragmentation of primary α(Co) phase induced by high undercooling is found to enhance the completion of peritectic transformation. In addition, the LKT/BCT dendrite growth model is modified in order to make it applicable to those binary alloy systems with seriously curved liquidus and solidus lines. The dendrite | Chongde Cao Xiaoyu Lu Bingbo Wei | 1999 | Chinese Science Bulletin1999，44，14： | 11 |
| 2 | Rapid growth of ternary eutectic un der high undercooling conditions显示文摘Rapid solidification of bulk Ag42.4Cu21.6Sb36 ternary eutectic alloy is accomplished by glass fluxing method,during which the maximum undercooling attains 114 K (0.16 TE). Under high undercooling conditions,the ternary eutectic consists ofε (Ag3Sb),(Sb)and θ(Cu2Sb)phases,instead of (Ag),(Sb)and θphases as predicted by the phase diagram.In the sample of small undercooling,the alloy microstructure is characterized by the mixture of primary θ(Cu2Sb),(ε+θ) and (ε+Sb) pseudobinary eutectics,and regular (ε+θ+Sb) ternary eutectic.With the increase of undercooling, θ (Cu2Sb) primary phase and pseudobinary eutectics disappear gradually,and ternary eutectic transfers from regular to anomalous structure.When undercooling exceeds 102 K,anomalous (ε+θ+Sb) ternary eutectic is the unique microstructure.Competitive nucleation and growth of these three eutectic phases is the main cause for the formation of complex growth morphologies.Based on the current experiments and theoretical calculations,it can be concluded that the intermetallic compound phaseθ(Cu2Sb) is the leading nucleating phase. | RUAN Ying CAO Chongde WEI Bingbo | 2004 | Science China(Physics,Mechanics & Astronomy)2004，47，6： | 10 |
| 3 | Rapid eutectic growth during free fall显示文摘Rapid eutectic growth of Sb-24%Cu alloy is realized in the drop tube during the free fall under the con-tainerless condition. Based on the analysis of crystal nuclea-tion and eutectic growth in the free fall condition, it is indicated that, with the increase of undercooling, microstruc-tural transition of Sb-24%Cu eutectic alloy proceeds from lamellar to anomalous eutectic structure. Undercoolings of 0 -154 K have been obtained in experiment. The maximum undercooling exceeds to 0.19TE. Calculated results exhibit that Cu2Sb compound is the primary nucleation phase, and that the primary Sb dendrite will grow more rapidly than the eutectic structure when undercooling is larger than 40 K. The eutectic coupled zone around Sb-24%Cu eutectic alloy leads strongly to the Cu-rich side and covers a composition range from 23.0% to 32.7%Sb. | Wenjing Yao Xiujun Han Bingbo Wei | 2002 | Chinese Science Bulletin2002，47，15： | 7 |
| 4 | Electrostatic levitation under the single-axis feedback control condition显示文摘An electrostatic levitator with a single-axis feedback control system was developed on the basis of electric field analysis and optimum design for levitation electrodes. In order to realize the stable levitation of various types of materials such as metals, inorganic materials and polymers, we made both experimental and theoretical investigations to solve the four key problems of electric field optimization, sample position detecting, sample charging control and levitation voltage minimization. Under the capacitive induction charging condition, a sample with the size of 2.6–4.5 mm usually bears positive charges amounting to 10-9 Coulomb. Because the single-axis feedback control system responds quickly, it takes the levitated sample only 0.1 s from leaving the bottom electrode until attaining a stable levitation in the upright direction. The levitated sample displays satisfactory levitation stability in both the upright and the horizontal directions owing to the constraining force produced by spherical electrodes. | HU Liang, WANG HaiPeng, XIE WenJun & WEI BingBo* Department of Applied Physics, Northwestern Polytechnical University, Xi’an 710072, China | 2010 | Science China(Physics,Mechanics & Astronomy)2010，53，8： | 7 |
| 5 | Understanding atomic-scale phase separation of liquid Fe-Cu alloy显示文摘Using liquid Fe 60 Cu 40 alloy as a model, the structure of liquid Fe-Cu alloy systems is investigated in the temperature range 1200 2200 K, covering a large metastable undercooled regime, to understand the phase separation of liquid Fe-Cu alloys on the atomic scale. The total pair distribution functions (PDFs) indicate that liquid Fe 60 Cu 40 alloy is ordered in the short range and disordered in the long range. If the atom types are ignored, the total atom number densities and PDFs demonstrate that the atoms are distributed homogenously in the liquid alloy. However, the segregation of Fe and Cu atoms is very obvious with decreasing temperature. The partial PDFs and coordination numbers show that the Cu and Fe atoms are not apt to get together on the atomic scale at low temperatures; this will lead to large fluctuations and phase separation in liquid Fe-Cu alloy. | WANG HaiPeng WEI BingBo | 2011 | Chinese Science Bulletin2011，56，32： | 7 |
| 6 | The liquid phase separation of Bi-Ga hypermonotectic alloy under acoustic levitation condition显示文摘Containerless treatment of Bi-58.5at%Ga hypermonotectic alloy is successfully performed with acous-tic levitation technique. Under acoustic levitation condition,the second phase (Ga) distributes almost homogeneously in solidification sample,opposite to macrosegregation in solidification sample under conventional condition. Stokes motion of the second liquid droplet (Ga) is significantly restrained un-der acoustic levitation condition. The analyses indicate that the melt vibration in the gravity direction forced by acoustic field can induce steady flow around the second liquid droplet,which influences droplet shape during its moving upward and consequently restrains Stokes motion velocity of the second liquid droplet. | HONG ZhenYu LV YongJun XIE WenJun WEI BingBo | 2007 | Chinese Science Bulletin2007，52，11： | 7 |
| 7 | Thermophysical properties of Ni-5%Sn alloy melt显示文摘The surface tension and specific heat of Ni-5%Sn alloy melt were measured by the oscillating drop method and the drop calorimetric method using electromagnetic levitation, respectively. The temperature coefficient of surface tension is 6.43×10-4 N·m?1K?1 within the temperature regime of 1464-1931 K. The enthalpy change was measured in the temperature range from 1461 to 1986 K, and the average specific heat was obtained as 43.03 J·mol?1K?1. Some other thermophysical properties, such as viscosity, solute dif-fusion coefficient, density, thermal diffusivity and thermal conductivity of this alloy melt, were derived based on the experimentally measured surface tension and specific heat. Using these thermophysical parameters, the relation between solute trapping and under-cooling in rapidly solidified α-Ni was calculated, and the theoretical prediction shows a good agreement with experimental data. | DAI Fuping CAO Chongde WEI Bingbo | 2006 | Science China(Physics,Mechanics & Astronomy)2006，49，2： | 7 |
| 8 | Ternary eutectic growth of Ag-Cu-Sb alloy within ultrasonic field显示文摘The liquid to solid transformation of ternary Ag42.4Cu21.6Sb36 eutectic alloy was ac- complished in an ultrasonic field with a frequency of 35 kHz, and the growth mechanism of this ternary eutectic was examined. Theoretical calculations predict that the sound intensity in the liquid phase at the solidification interface increases gradually as the interface moves up from the sample bottom to its top. The growth mode of (ε + θ + Sb) ternary eutectic exhibits a transition of 'divorced eutectic— mixture of anomalous and regular structures—regular eutectic' along the sample axis due to the inhomogeneity of sound field distribution. In the top zone with the highest sound intensity, the cavitation effect promotes the three eutectic phases to nucleate independently, while the acoustic streaming efficiently suppresses the coupled growth of eutectic phases. In the meantime, the ultrasonic field accelerates the solute transportation at the solid-liquid interface, which reduces the solute solubility of eutectic phases. | ZHAI Wei HONG ZhenYu WEI BingBo | 2007 | Science China(Physics,Mechanics & Astronomy)2007，50，4： | 6 |
| 9 | Phase separation and rapid solidification of liquid Cu_(60)Fe_(30)Co_(10) ternary peritectic alloy显示文摘The metastable liquid phase separation and rapid solidification of Cu60Fe30Co10 ternary peritectic alloy were investigated by using the drop tube technique and the differential scanning calorimetry method. It was found that the critical temperature of metastable liquid phase separation in this alloy is 1623.5 K, and the two sepa- rated liquid phases solidify as Cu(Fe,Co) and Fe(Cu,Co) solid solutions, respec- tively. The undercooling and cooling rate of droplets processed in the drop tube increase with the decrease of their diameters. During the drop tube processing, the structural morphologies of undercooled droplets are strongly dependent on the cooling rate. With the increase of the cooling rate, Fe(Cu,Co) spheres are refined greatly and become uniformly dispersed in the Cu-rich matrix. The calculations of Marangoni migration velocity (VM) and Stokes motion velocity (VS) of Fe(Cu,Co) droplets indicated that Marangoni migration contributes more to the coarsening and congregation of the minor phase during free fall. At the same undercooling, the VM/VS ratio increases drastically as Fe(Cu,Co) droplet size decreases. On the other hand, a larger undercooling tends to increase the VM/VS value for Fe(Cu,Co) drop- lets with the same size. | DAI FuPing, CAO ChongDe & WEI BingBo Department of Applied Physics, Northwestern Polytechnical University, Xi’an 710072, China | 2007 | Science China(Physics,Mechanics & Astronomy)2007，50，4： | 6 |
| 10 | The ninth-mode sectorial oscillation of acoustically levitated drops显示文摘We report on the ninth-mode sectorial oscillation of acoustically levitated drops excited by actively modulating sound pressure. A numerical computation based on the level set method was performed to model drop shape evolution by solving an incompressible two-phase flow problem. The calculated shapes of the oscillating drop are in good agreement with experimental observations. The relationship between the oscillation frequency and parameters describing the flattened drops is studied both experimentally and numerically. The frequency of the ninth-mode sectorial oscillation decreases with increasing equatorial radius and can be well-described by a modified Rayleigh equation. | YAN ZhenLin XIE WenJun GENG DeLu WEI BingBo | 2011 | Chinese Science Bulletin2011，56，31： | 5 |
| 11 | Dynamic solidification of Sn-38.1% Pb eutectic alloy within ultrasonic field显示文摘The dynamic solidification of Sn-38.1% Pb eutectic alloy within an ultrasonic field is investigated at a frequency of 35 kHz.As the sample height H is reduced,the effect of ultrasound on macrosegregation becomes more prominent,and the volume fraction of spherical eutectic cells increases correspondingly.When H equals the wavelength λ in liquid alloy,the introduction of ultrasound enlarges the distribution region of the primary (Sn) phase,but reduces the domains of the Sn-Pb eutectic and primary (Pb) phases.Meanwhile,a 'dendritic-equiaxed' structural transition occurs in the primary (Sn) phase,and its grain size is significantly reduced within the ultrasonic field.Once H decreases to λ/2 and λ/4,the ultrasonic field promotes crystal nucleation and suppresses further undercooling of the bulk liquid alloy.Theoretical analyses indicate that the local high pressure induced by the cavitation effect and the stirring effect due to acoustic streaming are the main factors dominating the eutectic growth mechanism during dynamic solidification. | ZHAI Wei HONG ZhenYu XIE WenJun WEI BingBo | 2011 | Chinese Science Bulletin2011，56，1： | 5 |
| 12 | Solidification characteristics of Pb-Sb hypereutecticalloy within ultrasonic field显示文摘The solidification of Pb-16%Sb hypereutectic alloy is investigated within ultrasonic field with a fre-quency of 15 kHz. It is found that the ultrasonic field promotes crystal nucleation and terminates the further bulk undercooling of the alloy melt. Theoretical analysis shows that the cavitation effect and the forced bulk vibration are the main factors that reduce the undercooling level. With the increase of ul-trasound intensity, the primary (Sb) phase experiences a growth mode transition from faceted to non-faceted branched growth, and the macrosegregation of primary (Sb) phase is gradually sup-pressed. In addition, the microstructures of Pb-Sb eutectic exhibit a conspicuous coarsening with in-creasing ultrasound intensity, and a structural transition of “lamellar eutectic—anomalous eutectic” occurs when ultrasound intensity rises up to 1.6 W/cm2. The ultrasonic field also changes the solute distribution adjacent to the solidification front, which lowers the Pb contents in primary (Sb) phase. | ZHAI Wei HONG ZhenYu XIE WenJun WEI BingBo | 2007 | Chinese Science Bulletin2007，52，6： | 5 |
| 13 | Heat transfer of micro-droplet during free fall in drop tube显示文摘To explore the heat transfer of micro-droplet during free fall in the drop tube, the falling velocity and microgravity level are calculated. The Newtonian heat transfer formulation is coupled with the classical heat conduction equation to predict the heat transfer process within micro-droplet. Based on the numerical solution by finite difference method with implicit Euler scheme,the temporal evolution of thermal information inside micro-droplet is obtained including the temperature distribution, cooling rate, temperature difference and gradient. To quantitatively reveal the mechanism how the various factors affect the heat transfer of micro-droplet, the effects of physical properties of liquid metal and cooling gas as well as the micro-droplet size are studied.As the important indicators of heat transfer process, the cooling rate and temperature difference are acquired to systematically investigate the relationship between thermophysical properties and heat transfer process of different metallic micro-droplets. | LI Ming Xing WANG HaiPeng YAN Na WEI BingBo | 2018 | Science China(Technological Sciences)2018，61，7： | 5 |
| 14 | Digital image processing of sectorial oscillations for acoustically levitated drops and surface tension measurement显示文摘A type of non-axisymmetric oscillations of acoustically levitated drops is excited by modulating the ultrasound field at proper frequencies. These oscillations are recorded by a high speed camera and analyzed with a digital image processing method. They are demonstrated to be the third mode sectorial oscillations, and their frequencies are found to decrease with the increase of equatorial radius of the drops, which can be described by a modified Rayleigh equation. These oscillations decay exponentially after the cessation of ultrasound field modulation. The decaying rates agree reasonably with Lamb’s prediction. The rotating rate of the drops accompanying the shape oscillations is found to be less than 1.5 rounds per second. The surface tension of aqueous ethanol has been measured according to the modified Rayleigh equation. The results agree well with previous reports, which demonstrates the possible application of this kind of sectorial oscillations in noncontact measurement of liquid surface tension. | SHEN ChangLe, XIE WenJun & WEI BingBo Department of Applied Physics, Northwestern Polytechnical University, Xi’an 710072, China | 2010 | Science China(Physics,Mechanics & Astronomy)2010，53，12： | 4 |
| 15 | Formation of ■ phase in Cu-Ge peritectic alloys显示文摘Rapid growth behavior of ■ phase has been investigated in the undercooling experiments of Cu-14%Ge, Cu-15%Ge, Cu-18.5%Ge and Cu-22%Ge alloys. Alloys of the four compositions obtain the maximum undercoolings of 202 K(0.17TL), 245 K(0.20TL), 223 K(0.20TL) and 176 K(0.17TL), respectively. As the content of Ge increases, the microstructural transition of 'α (Cu) dendrite + ■ peritectic phase →■ peritectic phase →■ dendrite + (ε +■ ) eutectic' takes place in the alloy at small undercooling, while the microstructural transition of 'fragmented α (Cu) dendrite + ■ peritectic phase →■peritectic phase →■ dendrite + ε phase' happens in the alloy at large undercooling. EDS analysis of the Ge content in ■ peritectic phase indicates that undercooling enlarges the solid solubility of α dendrite, which leads to a decrease in the Ge content in ■ phase as undercooling increases. In the Cu-18.5%Ge alloy composed of ■ peritectic phase, the Ge content in ■ phase increases when undercooling increases, which is due to the restraint of the Ge enrichment on the grain boundaries by high undercooling effect. | RUAN Ying DAI FuPing WEI BingBo | 2007 | Chinese Science Bulletin2007，52，19： | 4 |
| 16 | Rapid solidification of acoustically levitated Al-Cu-Si eutectic alloy under laser irradiation显示文摘Al-27%Cu-5.3%Si ternary eutectic alloy was melted using a YAG laser and then solidified while being acoustically levitated. A maximum undercooling to 195 K (0.24 TL) was achieved with a cooling rate of 76 K/s. The solidification microstructure was composed of (Al+θ+Si) ternary eutectics and (Al+θ) pseudobinary eutectics. During acoustic levitation, the (Al+θ+Si) ternary eutectics are refined and the (Al+θ) pseudobinary eutectics have morphological diversity. On the surface of the alloys, surface oscillations and acoustic streaming promote the nucleation of the three eutectic phases and expedite the cooling process. This results in the refinement of the ternary eutectic microstructure. During experiments, the reflector decreases with increasing alloy temperature, and the levitation distance always exceeds the resonant distance. Because of the acoustic radiation pressure, the melted alloy was flattened, and deformation increases with increasing sound pressure. The maximum aspect ratio achieved was 6.64, corresponding to a sound pressure of 1.8×104 Pa. | YAN Na GENG DeLu HONG ZhenYu WEI BingBo | 2011 | Chinese Science Bulletin2011，56，9： | 4 |
| 17 | Geometric optimization of electrostatic fields for stable levitation of metallic materials显示文摘Experimental and computational methods are used to optimize the electrostatic field for levitating metallic materials.The calculated launch voltage increases linearly with the distance between top and bottom electrodes.The combination of a larger top electrode diameter with a smaller bottom diameter may enhance the levitation ability because the electric field intensity near the levitated sample is strengthened.Top convex and bottom concave electrodes can guarantee good levitation stability but decrease the levitation force.The design of bottom electrode is crucial to attain not only a stable levitation state but also a higher levitation capability.As a measure characterizing the intrinsic levitation ability of various materials,the product of density and diameter of levitated samples can be used to determine the launch voltage for counteracting gravity according to a power relationship. | HU Liang WANG HaiPeng LI LiuHui WEI BingBo | 2013 | Science China(Technological Sciences)2013，56，1： | 4 |
| 18 | Materials Experiment on Tiangong-2 Space Laboratory显示文摘During the China's Tiangong-2(TG-2) flight mission, the experiments of 18 kinds of material samples were conducted in space by using a Multiple Materials Processing Furnace(MMPF) mounted in the orbital module of the TG-2 space laboratory. After the experiments of 12 kinds of samples of the first and second batches were completed successfully, astronauts packed and brought them back to the ground by ShenzhouII spacecraft. By studying processing and formation on semiconductor and optoelectronics materials, metal alloys and metastable materials, functional single-crystal, micro-and nano-composite materials encapsulated in sample ampoules both in space and on Earth, we expect to explore some physical and chemical processes and mechanism of the materials formation that are normally obscured and therefore are difficult to study quantitatively on the ground due to the gravity-induced convection, to obtain the processing and synthesis technology for preparing high quality materials, and lead to the improvement and development of materials processing techniques on Earth, and also develop the experiment device and comprehensive ability for materials experiment in microgravity environment. This report briefly introduces the main points of each research work and preliminary comparative analysis results of 12 samples carried out by scientists undertaking research task. | LI Xiangyang LU Ye MENG Xiangjian WANG Jianlu WANG Reng CHEN Lidong HUA Zile LI Xiaoya SHI Jianlin LIU Jinfeng XU Guisheng WEI Bingbo XIE Wenjun YIN Zhigang ZHANG Xingwang JIANG Hongxiang LI Hong LUO Xinghong ZHANG Haifeng ZHAO Jiuzhou WANG Binbin PAN Mingxiang | 2018 | 空间科学学报2018，38，5： | 4 |
| 19 | Dendritic and eutectic growth in Sb_(60)Ag_(20)Cu_(20) ternary alloy显示文摘The rapid solidification of Sb60Ag20Cu20 ternary alloy was realized by high under- cooling method, and the maximum undercooling is up to 142 K (0.18TL). Within the wide undercooling range of 40-142 K, the solidified microstructures are composed of (Sb), θ and ε phases. High undercooling enlarges the solute solubility of (Sb) phase, which causes its crystal lattice to expand and its crystal lattice constants to increase. Primary (Sb) phase grows in two modes: at small undercoolings non-faceted dendrite growth is the main growth form; whereas at large undercool- ings faceted dendrite growth takes the dominant place. The remarkable difference of crystal structures between (Sb) and θ phases leads to (θ + Sb) pseudobinary eutectic hard to form, whereas strips of θ form when the alloy melt reaches the (θ + Sb) pseudobinary eutectic line. The cooperative growth of θ and ε phases contrib- utes to the formation of (ε + θ ) pseudobinary eutectic easily. In addition, the crys- tallization route has been determined via microstructural characteristic analysis and DSC experiment. | RUAN Ying WEI BingBo | 2007 | Science China(Physics,Mechanics & Astronomy)2007，50，5： | 3 |
| 20 | Rapid dendrite growth in quaternary Ni-based alloys显示文摘The high undercooling and rapid solidification of Ni-10%Cu-10%Fe-10%Co quaternary alloy were achieved by electromagnetic levitation and glass fluxing techniques. The maximum undercooling of 276 K (0.16TL) was obtained in the experiments. All the solidified samples are determined to be α-Ni single-phase solid solutions by DSC thermal analysis and X-ray diffraction analysis. The microstructure of the α-Ni solid solution phase transfers from dendrite to equiaxed grain with an increase in undercooling, accompanied by the grain refinement effect. When the undercooling is very large, the solute trapping effect becomes quite significant and the microseg-regation is suppressed. The experimental measure-ment of α-Ni dendrite growth velocity indicates that it increases with undercooling according to the relation, V=8×10?2×?T1.2. | SONG Xianzheng WANG Haipeng RUAN Ying WEI Bingbo | 2006 | Chinese Science Bulletin2006，51，8： | 3 |
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