The DD3 single crystal alloy specimens with the orientation combination of 0°+30°and 0°+60° were TLP diffusion bonded with D1F amorphous foil interlayer alloy. The effect of the crystal orientation between the two bonded single crystal alloy specimens on the microstructure and property of the joint was investigated. The results showed that, in the middle part of the joint bonded by two specimens with different crystal orientations, there existed a boundary composed of γ′phases in the form of large block, which was vertical to the applied stress and so became the weak part of the joint. As a consequence, the stressrupture property of the joint was below to 40% of that of the base material, and all of the test specimens fracture at the bonding seam. However, using the same interlayer alloy and the same bonding parameters, the joint formed by two specimens with the same crystal orientation exhibited homogeneous microstructures, and the stressrupture property of the corresponding joint was comparable to that of the base material. So in order to obtain the joints of high property, it should make the two bonded specimens with the same orientations as more as possible.

The four types of hydrogels using acrylamide(AM) and isopropylacrylamide(NIPAM) as monomer, methylenebisacrylamide (MBA) and inorganic nanoclay lithium magnesium silicate hydrate (LMSH) as chemical and physical crosslinker, respectively, were prepared by freeradical polymerization in aqueous solution. The results show that, comparing with hydrogels crosslinked by MBA, the polyAM and polyNIPAM hydrogels using LMSH as physical crosslinking agent presents higher swelling ratios and lots of pore. The adsorption amount of crystal violet (CV) on polyAM and polyNIPAM hydrogels increases 58 times. In terms of adsorption and using effect, polyNIPAM hydrogel crosslinked by LMSH is the best choice for removing CV dye.

The natural cycle ageing which contained marinating in seawater and insolating was used to simulate and determine the durability of T300/epoxy composite made by the hand layup technics under marine environmental load. Natural ageing character of T300/epoxy samples was studied by changes in mass gain and mechanical property including tensile strength, tensile modulus, inplane shear strength and compression strength. The results show that after 140 days natural cycle ageing in Wuhan and Sanya, the mass gain increases with increasing time and the attenuation trend of mechanical properties is uniform. The ageing character of tensile modulus is inconspicuous. Tensile strength changes small, but inplane shear strength and compression strength have great attenuation extent. The residual strength of the samples in dryness state is stronger than that in wetness state.

With the specific nominal mean stress, considering the real operating situations of welded joints, the model for fast assessing the fatigue parameters and the residual fatigue life, was established by the infrared thermographic technique, realizing the fatigue performance evaluation of inhomogeneous welded joints using quantitative thermographic method. The damage evolution status was qualitatively analyzed by monitoring the hotspot variation on the welded joint surface. The results show that limitations of the traditional method are avoided, and that fatigue behavior parameters of inhomogeneous welded joints can be determined fast and accurately by quantitative thermographic method. Moreover, it is proved to be an effective way for health detection resorting to the hotspot variation detected realtimely during the fatigue process.

The ZnO-CeO₂ nanocomposite particles were prepared by heterogeneous method. The effects of different ratios of reactants, reactive temperature and pH on its absorption capability in UV ray region were investigated. Optimal preparation conditions were obtained. The ZnO-CeO₂ samples were characterized by FTIR , XRD and TEM. The results indicated that the prepared composite nanoparticles were ZnO and CeO₂, and the average size of the ZnO-CeO₂  sample was about 15nm; The UV absorption capability was investigated by UV-Vis. There was a broad peak between 245nm and 400nm in UV ray region. Its absorbing boundary extended to 400nm. The composite particle had a prosperous applied future as UVabsorbing material.

The density and mechanical property of ramie fiber and yarn which were treated by alkali and grafted by TDI on the optimal reaction conditions were studied. The molecular structure and crystal structure of ramie fiber were analyzed by IR and XRD. The results showed that, the density of ramie fiber and yarn which were treated by alkali and grafted by TDI was increased；the tensile strength of ramie fiber and yarn was decreased significantly. The tensile strength of ramie fiber treated by alkali declined 26.29%, and of the one grafted by TDI declined 29.13%(ultrasonic) and 22.67%（no ultrasonic）. The tensile strength of ramie yarn treated by alkali  declined 39.04%, and of the one grafted by TDI declined 35.51%.

The microstructural characteristics of the amorphous electroless Ni-W-P coatings before and after laser crystallization were evaluated by a quantitative XRD method. Wear behaviour of the coatings were investigated by means of measurement of microhardness, wear test and optical microscope and SEM observation. The results indicate that crystalline reaction of Ni₃P phase occurs at different scanning velocities. The  crystallization degree  of the coating increases with the decreasing  scanning velocity, but there is an incomplete crystallization for all coatings. At the scanning velocity of 7mm/s, the crystallization  degree  is 73.0%. The size of precipitated Ni₃P is larger than Ni at the scanning velocity (10mm/s) of critical precipitation of Ni₃P phase. The evolution of magnitude of both phases is opposite while the scanning velocity decreases. The sizes of both phases are in the range of nanoscale during the process of laser crystallization. Microhardness and wear resistance of the coating before and after laser crystallization are affected by the   crystallization degree, relative proportions of Ni and Ni₃P phases as well as grain sizes. Adhesive wear dominates at 7mm/s, and abrasive wear is the major form of the coating at 8mm/s. The wear resistance of the coating can be improved with fitting  crystallization degree and suitable sizes of both phases.

The Ni-SiC nanocomposite coatings were electrodeposited on copper substrate aided with ultrasonic. The effects of ultrasonic and the arrangement way of electrodes on the microstructure and properties of the composite coatings were discussed. The results indicated that the composite coatings were significantly refined by ultrasonic and secondary particles,the microhardness increased to HV760,and diffraction crystal plane of nickel (200) and (220) was varied, therefore, preferred orientation was inhibited in the process of grain growth. Compared to that the electrodes were placed in vertical, the thickness of the coating was 12.0μm and microhardness was HV343. This was attributed to the sedimentation of secondary particles covered cathode surface and reduced the deposition of nickel,when the electrodes were placed in horizon.

 The degradation process of heavy-duty coatings system composed of epoxy zinc rich primer, micaceous iron oxide intermediate, and chlorinated rubber top coatings in seawater was studied by the electrochemical impedance spectroscopy (EIS). The evolution of coatings capacitance was investigated to illuminate the water diffusion process and coefficient during coatings aging process. The results showed that the degradation process of the heavyduty coatings in seawater could be described in the two typical stages. The coating resistance decreased linearly at a rate of 1.9×10⁷Ω·h^-1 and 8381Ω·h^-1 before and after 120h respectively. The lnC_c-t^1/2 curve for heavyduty coatings indicated that the coating capacitance presented two typical stages as the immersion time increased, the coating capacitance increased rapidly in the beginning time of immersion (0-30h), and then tended to be a slow growth stage after 30h. According to the linear part of ln C_c-t^1/2 in the early immersion period, the water diffusion coefficient D was obtained and the value was 2.9076×10^-9cm²·s^-1.

The influences of laser scanning conditions on the silver micro/nanostructures in multiphoton photoreduction of metallic micro/nanostructures and morphology using femtosecond laser were investigated. The results indicated that increasing the distance between scanning points (d) could make the width of lines become smaller and extending the exposure of time (t) could make the lines broadening. Furthermore, the increasing of scanning times (N) led to the formation of large silver particles and lumps on the structures due to the fusion of silver nanoparticles which on the surface of metallic micro/nanostructures.

With pure Mg and SiO₂ powders as raw materials, an Mgbased metal matrix composite reinforced by MgO ceramic and Mg₂Si intermetallic was formed through selfassembly growth method. The differential thermal analysis (DTA) was performed on the samples and it was revealed that the insitu reaction between Mg and SiO₂ took place from 510℃ to 600℃. As a result of reaction, the MgO was formed, and the reduced Si continually reacted with excess Mg, forming Mg₂Si. The observation of scanning electron micrograph and energy dispersive spectrometry indicated that, in the sample made by ultrasonic assisted stirring, the insitu formed MgO covered the Mg₂Si intermetallic as a compact aggregate layer which had a strong bonding strength with the matrix. What’s more,the Vickers hardness tests showed that the Vickers hardness of ultrasonic assisted stirring sample was 40 percent higher than that of the sample made by generally stirring. The reaction mechanism between Mg and SiO₂ was concretely discussed.

Using YB00501 pressure transmitter  the plasma arc force in positive polarity was greater than that in reverse polarity was measured.The thermal and force models on aluminum alloy variable polarity plasma arc (VPPA) keyhole molten pool were built. The stability of keyhole molten pool and the forming mechanism of weld under the action of thermal and force in asymmetric positive and reverse polarity plasma arc were analyzed. By further analysis of aluminum alloy variable polarity plasma arc mechanical and thermal characteristics, the key welding influence factors on welding current and plasma air flow were mastered. According to the keyhole welding process testing, the reasonably selected positive and reverse polarity current amplitude and plasma air flow which keep thermal and force balance during  keyhole welding process provided theoretical support for getting stable technique parameters in aluminum alloy variable polarity plasma arc welding.

The research progress of the aids for the improvement of processing properties in high energetic solid propellants was summarized. Research and application of the processing aids were introduced according to the method to improve the processing performance of the propellant slurry, such as diluting the slurry, extending of the pot life, improvement the fluidity of the slurry, etc. The aids which could improve the fluidity of the particles and the mechanical properties of the propellant at the same time were much reported in recent years and were introduced emphatically. Some views on the further study of the multifunctional aids for high energetic solid propellants were presented.

The metal nanocrystals in carboncoated particle could be protected from the environment and still retain their intrinsic properties, which has received considerable attention in recent years for both its scientific and technological implications. The working principle of preparing carboncoated metal nanoparticles by arc discharge method was introduced. The research and development of the preparation method were briefly reviewed. The reaction path of metal and carbon, the types of the result product, and the formation mechanism of the carbon encapsulation were discussed.

The material selection evaluation based on material database can bring database full play in the mass memory and the powerful search function, and can give computer full play in the supercomputing power. Since such, the old complex process, which is the selection of the evaluating material and mass data initialization and model calculation, becomes shortcut, exact, simple and intelligent. On the base of the material database system construction, the functional module of the material adaptability evaluation method was developed, and the computer aided selection evaluation of material based on the material database was realized. This is a beneficial try in the direction of the material database system intelligent development. The attained quantified evaluation results directly reflect the difference between the close property and different property of the material selection schemes. The subjectivity and blindness which are generated when the material selection is only based on the experience decrease.

The effects of Si contents on the variation of phase structure, microstructure characteristic and mechanical properties of AlCoCrNiSix highentropy alloys were characterized respectively by using of XRD, SEM, EDS and microhardness testing. The results reveal that alloys phase structure is transformed from the single bcc1 phase structure to the mixed bcc1+ bcc2 phase structure with the increase of Si contents. The bcc1 is an AlNi solid solution structure and the bcc2 is CrSi solid solution structure. The ascast microstructure of alloys has a change from the dendritic crystal morphology to the cellular crystal morphology with the Si content increasing. Al and Ni elements mainly exist in the dendritic crystal and Si element segregates in the interdendritic region within the ascast microstructure. The Si element plays an important role in the increasing hardness of the AlCoCrNiSix alloy significantly, the highest microhardness is up to HV991.

The corrosion behavior of X80 steel in three kinds of simulated soil solution, was investigated by methods of mass loss measurement, scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) and Xray diffraction (XRD). The results show that X80 steel is uniform corrosion in simulated solution of Shanshan and Xinzhou soil, and pitting corrosion occurs on X80 steel in simulated solution of Zhangshu soil. The ranking of the corrosion rate of X80 steel in different simulated solution is Zhangshu, Xinzhou and Shanshan. The saltcrystallization of CaSO4?2H2O, which could inhibit the erosion effects of Cl- and dissolved oxygen on X80 steel, continuously deposit on the surface of corrosion products in Shanshan simulated solution, and slow down the uniform corrosion rate as well. However, the corrosion product layer that could not provide effective corrosion protection for X80 steel in Zhangshu simulated solution, makes the corrosion of X80 steel become more serious with the increasing of immersion time, and finally results in pitting corrosion of X80 steel.

In order to settle the problem for measuring the thickness of laser cladding coating by nondestructive method, the surface acoustic wave was used according to the properties of surface acoustic wave in material. The crosscorrelation function, which was usually used to calculate the difference in time of flight between two different signals, was used. The results show that the propagation velocity of surface acoustic wave in laser cladding coating is faster and faster with the thickness of coating increasing, and by using crosscorrelation function for calculating the difference in time of flight, the curve between thickness of coating and difference in time of flight, which can be used to measure the thickness of laser cladding coating, is calculated, and the fitted result, which could be used to measure the thickness of coating, is obtained by using cubic polynomial. At last, the fitted result of cubic polynomial was proved by laser cladding coating with different thickness, and the influences that affected the experimental result were analyzed. The results show that the method that is represented can be used to evaluate the thickness of laser cladding coating.

According to the elasticity theory，comparing the core material mechanical states in the sleeve under static pressure and the core mechanical states in the sandwich structure under deep water static pressure environment, the bushing test method adapted to study the creep characteristics of viscoelastic core materials was presented. The quasistatic compression and bushing compression creep tests for three different microspheresreinforced polyurethanemodified epoxy resin sound absorption materials (PUEPM) were carried out, the creep behavior of the core materials was obtained. The results show that the delaminated PUEPM core with low content glass microsphere and high content chopped fiber has preferable creep performance. The PUEPM core with higher content glass microsphere has higher resilience performance. The PUEPM core of type B has better comprehensive mechanical properties.

Microstructures and properties of 7050 aluminum alloy sheet after creep aging and artificial aging were studied by optical microscopy (OM), transmission electron microscopy (TEM), electronic tensile test and exfoliation corrosion test respectively. The results show that the loaded stress during creep aging generates continuously deformation, which provides a large amount of nucleation points for the precipitation of the η′ particles. The size of the η′ particles is smaller than that of the artificial aging. Especially, the precipitation free zone is narrower than that of the artificial aging, and grain boundary precipitates are discontinuous. The tensile strength and the resistance to exfoliation corrosion of the creep aging samples are better than those of the artificial aging.

On basis of reaction theory of urea and formaldehyde which were used as microcapsule shell materials, preparation technology of microcapsules containing αolefin drag reducing polymer was studied by using in situ polymerization method with urea and formaldehyde as shell materials. Preparation, storage stability and dissolving property of microcapsules were studied by using particle analyzer, FTIR, simultaneous thermal analyzer and simulation circular oil evaluation system of drag reducing rate and so on. The results show that, when microcapsules containing αolefin drag reducing polymer are prepared by in situ polymerization of urea and formaldehyde in acidic conditions, the preparation technology has properties that reaction implements in mild conditions, polycondensation is easily held and the reaction accomplishes quickly. The particle size distribution of microcapsules containing αolefin drag reducing polymer with poly (ureaformaldehyde) as shell material concentrates on 200μm. Microcapsules can keep condition of smooth small balls for long time and have excellent thermodynamic stability. The results of untistatic pressure storage stability and thermodynamic stability show that, microcapsules meet the qualifications of storage stability. Microcapsules containing αolefin drag reducing polymer with poly (ureaformaldehyde) as shell material have excellent dissolving property in oil. The drag reducing rates of microcapsules containing αolefin drag reducing polymer with poly (ureaformaldehyde) as shell material and uncoated αolefin drag reducing polymer particles are similar. Though there is some time delay in drag reducing rate to microcapsules contrasted with uncoated particles, the peak value of drag reducing rate is equivalent, and meets the standard of practical in situ engineering application.

Casting defects are deleterious to the mechanical properties of nickelbased single superalloys, the decrease of casting defects is benefit for improving mechanical properties and reducing the cost. Some important casting defects formed in the directional solidification process are discussed, including porosity, freckles, misorientation and stray grains. Based on the features and formation mechanisms for the defects, the influence of alloy composition, processing parameters and casting structure on the casting defects is analyzed. Meanwhile, the suggestions for reducing casting defects are pointed out.

Through the inspection of ultrasonic Δ technique and TOFD method on simulate flaws, concluded signal oscillogram and B/C scan of flaws. The signal characteristics of ultrasonic Δ technique and TOFD method were analyzed and interpreted. The results show that the defects which are perpendicular to the surface can be identified and located effectively, and can overcome surface blind area effectively, and the recognition capibility for defects is not limited by the orientation of them. From the results it can be seen that the achieved flaw sensitivity and probability of detection are substantially better than TOFD method.

SiO2f/SiO2 composite was successfully joined to TC4, Ti3Al and TiAl using Ag-Cu-Ti brazing foils at 880℃ for 10min and the sound joints were formed. The microstructures of three kinds of joints showed that a thin reaction layer was formed near the surface of SiO2f/SiO2 matrixes where elements Ti and O were enriched. During the brazing, element Ti in the brazing filler as well as a part of dissolved Ti from base metals together diffused to the surfaces near the composites and reacted with SiO2 and finally formed Ti-O phase. According to the atom ratio of Ti and O, it was deduced that the Ti-O phase should be Ti2O phase. The white microstructures and the grey microstructures existed in the three brazing seam. The former was mostly Ag-based solid solution and the latter mainly contained Ti and Cu that formed Ti-Cu phase.

CuAl2O4/TiO2 thin film photoanodes were prepared by doping spinel CuAl2O4 nanocrystallineprepared by the citrate method into P25 (degussa, TiO2), and then assembled into Dye-sensitized solar cells(DSSC) and characterized the photoelectric properties. The results showed that performance of DSSC increase when doped CuAl2O4. When the doping amount is 2%（mass fraction）, the photoelectric conversion efficiency was 39.1% higher than the pure TiO2 thin film photoanodes.

The effect of re-shot-peening treatment on the residual stress and room temperature fatigue life of initially shot-peened TC18 titanium alloy was investigated. The change of surface residual stress and fatigue life after re-shot-peening were examed by X-ray diffraction and rotating-bending fatigue tester, respectively. The results show that the surface residual stress relaxed in the range of 30%-50% because of pre-fatigue test, and that re-shot-peening successfully recovered the relaxed surface residual compressive stress up to the 50%-70% of the original. Further, compared with the samples excluding re-shot-peening, fatigue life of TC18 titanium alloy can be increased by 75% when re-shot-peened after the suitable pre-fatigue cycle.

The thermoplastic composites, which are known for their weldability, recyclability, chemical resistance, and rapid forming, will become common engineering materials in aerospace industry. There are some physical phenomena during fiber placement process, which involves some fields and cross-fields, such as heat transfer, thermomechanics, crystallization kinetics, Newtonian fluid mechanics and so on. Based on above theories, this article analyses theoretical models of heating process, cooling process, interlaminar bond strength, fiber placement compaction load and thermal residual stress, and discusses the influence factors of final products performance, such as matrix material crystallinity, the degree of inter laminar intimate contact, the degree of interlaminar diffusion and so on. The research achievements and research process are summarized and analyzed in this paper, and some problems which still existed and need to be resolved are discussed. The future development trend of fiber placement is also predicted.

Two heats of high Cr content cast Ni-base superalloy K4648, which possess significant differences on impact ductility, were investigated comparatively. The cleanliness of K4648 master alloy was studied by chemical analysis on the alloy composition and gas content, electron beam button (EB button) technique evaluation on inclusions and microstructure observation of chromium metal used in raw materials. The results indicate that the two heats of K4648 master alloy have no obvious difference in major constituent. However, 1# master alloy possesses a high oxygen level of （20.5?75）?10-6, which is much higher than 6?10-6 of 2# alloy. The impact ductility of 1# alloy is less than half that of 2# alloy and lower than the K4648 specification requirement of 19.6J/cm2. The electron beam button (EB button) experiment could effectively aggregate the inclusions in specific region. The inclusions were identified as (Y,Ce)-rich oxide and Al-rich oxide. It is evident that the addition of rare earth (RE) element such as yttrium and cerium in high Cr content cast Ni-base superalloy K4648 can snatch the free oxygen or sulfur, and form stable RE oxides or sulfides to purify the master alloy. About 15%（atom fraction） element O is solusionized in the chromium metal matrix which is used in raw materials for K4648 master alloy. Some Cr-rich oxides and (Cr,Al,Si)-rich oxides distributes in the Cr matrix. In addition, a N-bearing and O-depletion zone exists in the Cr matrix. The Vickers microhardness of this region can reach 8.2GPa, which is 6 times harder than 1.3GPa of Cr matrix, indicate that the element N can harden and embrittle the chromium metal.

The hydrogen induced delayed fracture behavior of a newly developed low carbon Mn-B-Ti type cold hardening microalloyed bainitic steel was studied using electrochemical charging and slow strain rate test (SSRT). It is found that charging of hydrogen significantly impairs the delayed fracture property of specimen both at as-hot rolled and as-cold drawn conditions. The decrease of anti-delayed fracture property is more noticeable when cold drawing reduction γ is lower than 20%. However, aging treatment has a beneficial effect on improving the anti-delayed fracture property of cold drawn specimen, and this improvement is more noticeable when aging temperature is higher than 200℃.

By Heating On-line Partitioning (HOP) method to obtain (B+M/A ) dual phase, the microstructure and property of a dual phase pipeline steel are investigated. The results show that , in the context of meeting the strength and toughness requirements of the second west-east gas pipeline project in China, the （B+M/A） dual phase pipeline steel also possesses a lower yield/tensile ratio and higher uniform elongation, showing excellent deformation ability. The bainitic matrix, M/A component and the precipitation of carbonitride are the microstructure characteristics of experimental steel.

A method for the determination of impurity elements Na, K, Mg and Ca in high purity silicasol by FAAS has been developed. Under the optimum condition, the detection limits of Na, K, Mg and Ca are 0.0047，0.0060，0.0036，0.028μg/mL.The recovery were between 92.5%-112.5%,RSD were all less than 10%.The methods is accurate, rapid and convenient.

Magnesium alloys were treated with micro-arc oxidation in a solution containing NaAlO2 at a constant applied current density. The effect of concentration of NaAlO2, glycerol, NaF in electrolyte and current density and oxidation time on voltage-time response of micro-arc oxidation process and coating thickness was also investigated. The results showed that sparks could be seen at the anode surface when the electrolyte only contained NaAlO2, the addition of glycerol can obviously restrain point discharge, the addition of NaF increased the coating thickness considerably. With the increase of the current density, ignition time of micro-arc oxidation become shorter. While the break voltage had no obvious change, and coating thickness increased obviously. The surface morphology of micro-arc oxidation coating was observed by scanning electron microscopy (SEM). The results showed that obvious pores and discharged tunnels which were melting and combined together can be seen on the coating surface.

The influence of friction and wear performance with palygorskite (P) /Ag nanocomposite lubricant additive on 45# steel45# steel pair treated by quenching and tempering were investigated by MMU10G friction wear testing machine in the condition that  friction surfaces were lubricated by the 150N base oil contained P/Ag composite nanomaterials in the mass fraction of 4%. Wear mass losses were estimated by weighing, and the topographies of worn surfaces were characterized by SEM and the main elements of the final surfaces were detected by EDX, moreover, using metallographic microscope observed the topography of autorestoration film at different growth stages. The results show that the nanoP/Ag composite additive reduces the wear mass loss of the 45# steel45# steel pair as high as 37.5%. The main elements of autorestoration film contain Fe,Si,O,C,Al,Mg,Ag, which proves that the composite additive participates in the forming of autorestoration film. The autorestoration film mainly forms in the time after 10h（or after running for 18km）.

Method of experiment and data processing using digital speckle correlation method to investigate sheet’s anisotropy was systematically introduced, then the anisotropy and its evolution of SPCC steel sheet and AA6061 aluminum sheet were researched. The results show that: the speckle strain measuring method is an effective tool to obtain the mechanical properties of sheets, whose greatest advantage is its capability to capture the whole strain field during deformation, and this is key to study mechanical properties of materials under complex loading conditions; for the SPCC steel sheet, the anisotropy of flow stress is not distinct, while the total and incremental Lankford coefficient (r values and r′ values) show obvious anisotropy, moreover its values decrease with the increasing of deformation, which is different with the constant Lankford coefficient by traditional strain measuring using extensometer; for the AA6061 aluminum sheet, the anisotropy of flow stress and r value are not obvious, however, the elongations of specimens in different directions to rolling show an distinct anisotropy, and the working hardening rate of flow stress and r′ value appear a sharp fluctuation when the true tensile strain is between 0.15 and 0.20; the anisotropy of the two sheet’s strain increases gradually with the increasing of deformation, especially for SPCC steel sheet.

Microstructural and mechanical characteristics of friction stir welded 6005A aluminum alloy were investigated by means of optical microscope, scanning electron microscopy (SEM), transmission electron microscope (TEM), tensile test machine and Vickers hardness tester. The results show that the nugget zone (NZ), thermo-mechanically affected zone (TMAZ) and heat affected zone (HAZ) are characterized by a fine equiaxed, elongated and coarse grain structures, respectively. All the precipitates dissolved in the NZ, and the TMAZ contains high density dislocation, and the HAZ shows over-aged state. Compared with the base metal, the FSW joint has a reduction in strength and elongation, and there is a distinctly soften region where the minimum hardness value located in HAZ of advancing side. At the optimum welding parameters (rotation speed of 1200r/min and welding speed of 200mm/min), the tensile strength and elongation of the FSW joint are equivalent to 72% and 69% of those of the base metal, respectively.

A ODS ferritic steel powder with the chemical composition (mass fraction/%)of Fe-14Cr-05Ti-0.35Y2O3 was prepared by mechanically alloying (MA), and the element distribution was homogenous. The MA powder was consolidated by hot isostatic pressing (HIP), followed by forging and annealing. Compared to 14CrNA steel without ODS particles, the tensile strength of 14CrODS steel was excellent，but not so good compared with MA957, thus need improvement. The ductility of 14CrODS was much better than MA957, and could be enhanced further by forging. However, residual stress existed during forging, making the 14CrODS steel brittle in room temperature tensile tests. Annealing could remove the residual stress and significantly improve the ductility of 14CrODS, which was more excellent than MA957.

The reliability method was applied to analyze the influence of the seal structure parameters on the air-tight performance of aero-port. The Ogden constitutive model was fitted based on compression experimental data of two types of aero-port sealing strip, which was applied to simulate the implicit response of secondary contact force between the door body and door frame by FEM. The seal structure’s parameters such as closing-stroke, assembly dimension, and baffle size etc were treated as random variables, the reliability of the two sealing strips types was compared by Monte Carlo method. The mean value sensitivity and variance sensitivity of above parameters were obtained. The results were helpful for the sealing strip selection and seal structure optimum design.

Nano-Pd particles were prepared using ultrasonic irradiation in the palladium(Ⅱ) chloride H2O/EtOH(5/1,V/V) solution by the addition of a quantity of hexadecyl trimethyl ammonium bromide(CTAB) and sodium dodecyl sulfonate(SDS). The samples were characterized by XRD，TEM，selected area electron diffraction (SAED)，HRTEM and low temperature nitrogen adsorption-desorption. The effects of the composition of CTAB and SDS on the growth morphology of palladium nanoparticles were investigated. The electrocatalytic properties of the nano-Pd modified glassy carbon electrode (Pd/GCE) for formaldehyde oxidation were also investigated by cyclic voltammetry. The results indicate that a promising possibility of a size and morphology for the nano-Pd particles are controled by adjusting the composition of CTAB and SDS. The polygonal nano-Pd particles with a distributed size of 10-20nm are obtained when the molar ratio of CTAB∶SDS is 1∶1 and the reaction time is 60min. The nanoparticles obtained by addition of two surfactants (CTAB and SDS) increase the BET surface area by 14m2?g-1 compared to that obtained without surfactant, which show the excellent electrocatalytic activity for the oxidation of formaldehyde.

The 150N base oil containing 2% and 4% mass fraction of nano-palygorskites modified with KH550 as additive were prepared. The anti-wear,friction-reducing and self-repairing behaviors of nano-palygorskites as additive in base oil were observed on the MMU-10G abrasive-wear tester. The wear loss of the sample was studied by electronic balance (EB). The morphographies of the worn surfaces were analyzed by means of scanning electron microscopy (SEM) and optical microscope. Elemental analysis was performed using an energy-dispersive X-ray (EDX) microanalyzer. The results show that the lubricating base oil containing 2% mass fraction of nano-palygorskites as additive has very weak self-repairing performance to 45# steel tribo-pair, the wear loss decreases limited and the anti-wear only occurs in early running-in stage; Lubricating base oil containing 4% mass fraction of nano-palygorskites as additive exhibits better anti-wear and self-repairing performance. Total wear loss decreases observably as high as 26.5% compared to that of pure base oil. Self-repairing films made up of characteristic elements of palygorskite in patchy distribution are observed on the surface of the sample.

The environmental conditions of aircraft tank water was simulated to study the corrosion behavior and characteristic of 30CrMnSiNi2A steel by corrosion area, corrosion mass loss rate, content of dissolved oxygen and pH in simulated tank water, corrosion potential of high-strength steel and so on. The results indicated that the corrosion process of 30CrMnSiNi2A steel in the simulated tank water was divided into three states: rapid corrosion stage came from 0h to 24h in which corrosion area was small and corrosion rate was fast; medium corrosion stage came from 24h to 168h in which most of the area was corroded and corrosion rate slowed down; slow corrosion stage came from 168h to 480h in which all of the area was corroded and corrosion rate was slow. With time going on, content of dissolved oxygen gradually reduced at first and then kept steady; pH value rapidly increased at first and then fluctuated within a narrow range; corrosion potential changed as decreasing exponential function. In addition, EIS and Tafel polarization curves indicated that corrosion rate of 30CrMnSiNi2A steel at three characteristic pH(4.2,4.8,5.2) decreased with pH value increasing.