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Journal of Materials Science & Technology 2023年第23期154卷 43-53页

作者： Lin Wang Zhipeng Long Long Hou Song Yan Baode Sun Xi Li Shanghai Key Lab of Advanced High-temperature Materials and Precision Forming Shanghai Jiao Tong University Shanghai 200240 China State Key Laboratory of Advanced Special Steels Shanghai University Shanghai 200072 China

The effects of a high magnetic field on the evolution of the single-phase interface and the liquid-solid interface energy in Al-Cu alloy were investigated *** is found that the application of the magnetic field has a significant promotion effect on the migration of liquid droplets,accelerating the formation of the single-phase *** should be attributed to the thermoelectric(TE)magnetic convection in the droplets which has enhanced the diffusion and increased the migration speed of liquid ***,the effect of the high magnetic field on the solid-liquid interface energy is analyzed by an improved grain boundary groove(GBG)*** average solid-liquid interface energy of theα-Al/Al-Cu and Al2Cu/Al-Cu systems increases and decreases with the increase of the magnetic field,*** above experiment results are well explained based on the formation and interaction of the magnetic dipole at the solid-liquid ***,experimental results reveal that the magnetic-field-induced interface energy increases and decreases the nucleation undercooling of the Al-30wt.%Cu alloy and Al-35wt.%Cu alloy,*** studying the effect of the magnetic-field-induced interface energy on the nucleation undercooling,the understanding of the interface energy-induced nucleation undercooling deepens.

关键词： High magnetic field interface energy Nucleation undercooling Grain boundary groove

Surface Characterization and in Vitro Blood Compatibility of Poly (Ethylene Terephthalate) Immobilized with Hirudin

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Plasma Science and Technology 2010年第2期12卷 235-239页

作者：李方王进孙鸿黄楠 Key Laboratory of Advanced Technologies of Materials (Southwest Jiaotong University) Ministry of Education Southwest Jiaotong University Petroleum Engineering Institute Southwest Petroleum University

Poly （ethylene terephthalate）（dacron, PET） films were exposed under argon plasma glow discharge with different glows and induced polymerization of acrylic acid（AA） in order to in- troduce carboxylic acid group onto PET （PET-AA） assisted by ultraviolet radiation（UV）. Hirudin- immobilized PET （PET-HRD） films were prepared by the grafting of PET-AA, followed by chem- ical reaction with hirudin. The surface structure of the treated PET was determined by X-ray photoelectron spectroscopy （XPS）. The wettability, surface free energy, and interface free energy of the films were investigated by contact angle measurement. The blood compatibility of the films was assessed by platelet-adhesion test and fibrinogen conformational change measurements to eval- uate the viability of the materials in biomedical engineering. Measurement by scanning electron microscopy （SEM） revealed that the amounts of adhered, aggregated and morphologically changed platelets were reduced on the hirudin-immobilized PET films. Enzyme-linked-immunoassay mea- surements that disclosed fibrinogen conformational changes showed results consistent with the platelets＇ behavior.

关键词： hirudin blood compatibility poly (ethylene terephthalate) interface energy surface energy

interface structure of Ag(111)/SnO_(2)(200)composite material studied by density functional theory

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Science China(Technological Sciences) 2009年第5期52卷 1258-1263页

作者： FENG Jing CHEN JingChao XIAO Bing YU Jie Key Laboratory of Advanced Materials of Precious-Nonferrous Metals Ministry of Education of Chinaand Key Laboratory of Advanced Materials of Yunnan ProvinceKunming University of Science and TechnologyKunming 650093China School of Materials Science and Engineering Xi’an Jiaotong UniversityXi’an 710049China

Electric contact material of Ag/SnO2 was successfully synthesized by in situ process *** in-terface structure was characterized by high-resolution transmission electron microscopy(HTEM) and simulated at atomic scale on *** mean-square displacements of atoms near the interface were calculated,and the results showed that near the interface both Ag side and SnO2 were mis-matched and this effect decays rapidly far from the *** inspecting the calculated density of states(DOS),we found that the electric-conductivity of this composite material was decreased because of the localized 4d and 2p electrons of Ag and O near the Fermi surface,*** density changed acutely across the interface,so that there was no extra compound precipitated.A mi-cro-electric field also formed in the whole material due to the interface structure,and this may affect the electron conduction and the related electric-conductivity of the *** is found that the interface cohesive energy of Ag(111)/SnO2(200) was-3.50 J/m2,which is higher than the experimental results.

关键词： electric contact material reactive synthesis interface energy structure relaxation electron structure Ab initio

Effects of external stress aging on morphology and precipitation behavior of θ'' phase in Al-Cu alloy

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Transactions of Nonferrous Metals Society of China 2014年第7期24卷 2282-2288页

作者：傅上易丹青刘会群江勇王斌胡湛中南大学材料科学与工程学院长沙410083 中南大学有色金属材料科学与工程教育部重点实验室长沙410083

The exposure of Al-5Cu alloy to an external stress with normal aging was carried out. The effects of external stress-aging on the morphology and precipitation behavior of θ＂ phase were investigated by transmission electron microscopy （TEM）, differential scanning calorimetry （DSC） and first principle calculation. The size of the θ＂ phase precipitated plates in stress-aging （453 K, 6 h, 50 MPa） is 19.83 nm, which is smaller than that of those present （28.79 nm） in stress-flee aging （453 K, 6 h）. The precipitation process of θ＂ phase is accelerated by loading external stress aging according to the analysis of DSC results. The apparent activation energy for the external stress-aging is 10% lower than the stress-free one. The first principle calculation results show that the external stress makes a decrease of 6% in the interface energy. The effects of the stress on aging process of the alloy are discussed on the basis of the classical theory. The external stress changes the morphology and precipitation behavior of θ＂ phase because the critical nucleation energy is decreased by 19% under stress aging.

关键词： Al-Cu alloy stress aging morphology precipitation behavior first principle calculation interface energy

Stress/strain aging mechanisms in Al alloys from first principles

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Transactions of Nonferrous Metals Society of China 2014年第7期24卷 2130-2137页

作者：罗康臧冰傅上江勇易丹青中南大学材料科学与工程学院长沙410083 中南大学教育部有色金属材料科学与工程重点实验室长沙410083

First-principles based calculations were carried out to explore the possible mechanisms of stress/strain aging in Al alloys. Potential effects of temperature and external stress/strain were evaluated on the solvus boundary of Al3Se in Al-Sc alloy, and the interface energy of Al/θ＂ in Al-Cu alloys. Results show that applying tensile strain/stress during conventional aging can significantly decrease the solubility entropy, by red-shifting the phonon DOS at high states. The resulted solvus boundary would shift up on the phase diagram, suggesting a reduced solubility limit and an increased maximum possible precipitation volume of AlaSc in Al-Sc alloy. Moreover, the applied strain/stress has different impacts on the formation energies of different orientated Al/θ＂ interfaces in Al-Cu alloys, which can be further exaggerated by the Poisson effect, and eventually affect the preferential precipitation orientation in Al-Cu alloy. Both mechanisms are expected to play important roles during stress/strain aging.

关键词： stress aging solubility limit interface energy first-principles

Mode-I fracture and durability of FRP-concrete bonded interfaces

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Water Science and Engineering 2008年第4期1卷 47-60页

作者： Qiao Pizhong Xu Yingwu Department of Civil and Environmental Engineering Washington State University Pullman WA 99164-2910 U.S.A. Department of Engineering Mechanics College of Civil Engineering Hohai University Nanjing 210098 P. R. China Department of Civil Engineering The University of Akron Akron OH 44325-3905 U. S. A.

In this study, a work-of-fracture method using a three-point bend beam （3PBB） specimen, which is commonly used to determine the fracture energy of concrete, was adapted to evaluate the mode-I fracture and durability of fiber-reinforced polymer （FRP） composite-concrete bonded interfaces. interface fracture properties were evaluated with established data reduction procedures. The proposed test method is primarily for use in evaluating the effects of freeze-thaw （F-T） and wet-dry （W-D） cycles that are the accelerated aging protocols on the mode-I fracture of carbon FRP-concrete bonded interfaces. The results of the mode-I fracture tests of F-T and W-D cycle-conditioned specimens show that both the critical load and fracture energy decrease as the number of cycles increases, and their degradation pattern has a nearly linear relationship with the number of cycles. However, compared with the effect of the F-T cycles, the critical load and fracture energy degrade at a slower rate with W-D cycles, which suggests that F-T cyclic conditioning causes more deterioration of carbon fiber-reinforced polymer （CFRP）-concrete bonded interface. After 50 and 100 conditioning cycles, scaling of concrete was observed in all the specimens subjected to F-T cycles, but not in those subjected to W-D cycles. The examination of interface fracture surfaces along the bonded interfaces with varying numbers of F-T and W-D conditioning cycles shows that （1） cohesive failure of CFRP composites is not observed in all fractured surfaces; （2） for the control specimens that have not been exposed to any conditioning cycles, the majority of interface failure is a result of cohesive fracture of concrete （peeling of concrete from the concrete substrate）, which means that the cracks mostly propagate within the concrete; and （3） as the number of F-T or W-D conditioning cycles increases, adhesive failure along the interface begins to emerge and gradually increases. It is thus concluded that the fracture proper

关键词： repair and strengthening of concrete structures FRP composites FRP-concrete bonded interface mode-l fracture durability freeze-thaw wet-dry interface energy