Copper-graphite composites were prepared by spark plasma sintering (SPS) using copper-coated graphite powder. Hydrophobic surfaces were successfully constructed by chemical etching and surface treatment. The density, metallographic structure, microstructure, Shore hardness, resistivity, water contact angle, and friction/wear properties of the composites were investigated using the Archimedes drainage method, a metallographic microscope, a scanning electron microscope, a hardness tester, a resistometer, a surface science tester, and a friction tester. The results showed that the relative density and Shore hardness of the copper—graphite composites increased slightly from 90.04% and 56 HSD to 92.66% and 59 HSD, respectively, when the sintering temperature increased from 700 to 900 °C. The copper and graphite phases in the copper-graphite composites were uniformly distributed with a continuous and network-like structure at various sintering temperatures. The interface between the copper and graphite was in good condition, without any obvious cracks or voids. The optimum process for hydrophobic surface construction included etching with a 1 mol/L K₂Cr₂O₇-H₂SO₄ solution for 1 min, and soaking in a 0.09 mol/L cetylbenzene sulfonic acid alcohol solution for 1 h. The contact angle of the copper—graphite composite reached 130°. Hydrophobic treatment was beneficial for reducing the friction coefficient (from 0.18–0.19 to 0.13–0.15) and the wear rate (from 4.1–6.2×10⁻³ to 1.1–2.1×10⁻³ mm³/(N·m)), demonstrating obvious antifriction and wear-resisting properties. The resistivities of the hydrophobic-treated samples increased slightly, from (4–8)×10⁻⁷ Ω·m to (5–15)×10⁻⁷ Ω·m, meeting the resistivity requirements of copper-graphite composite pantograph sliders and current receiver sliders in actual working conditions.

Pressure-driven reverse osmosis membrane has important application in seawater desalination. Inspired by the structure of aquaporin, we established and studied the mechanism of the structure of multilayer graphene with tapered channels as reverse osmosis. The water flux of multilayer graphene with tapered channels was about 20% higher than that of parallel graphene channel. The flow resistance model was established, and the relationship between flow resistance and opening angles was clarified. The relationship between flow resistance and outlet size was also described. By means of molecular dynamics simulation, slip coefficients of multilayer graphene with tapered channel were obtained and verified by the contact angle of water. Results show that the permeability of graphene with tapered channel is about three orders of magnitude higher than that of commercial reverse osmosis membrane and the desalination rate is 100%. Temperature difference between the two sides of the tapered channel will promote the water flux positively.

Al₂O₃-SiO₂ sols were synthesized by using aluminum chloride hex hydrate and tetraethoxysilane (TEOS) as precursors, deionized water and ethanol mixture as the solvent, and propylene oxide as the coagulant aids. Alumina coatings were prepared on the surfaces of hollow quartz filament fiber, then a new lightweight and thermal insulating material were successfully prepared by impregnating Al₂O₃-SiO₂ sol into a needle fabric made by coated hollow quartz filament fiber. The coated quartz fiber, aerogels and composites were characterized by Fourier transform infrared spectroscopy(FTIR), X-ray diffraction(XRD), energy dispersive spectroscopy(EDS), nitrogen adsorption-desorption(BET), scanning electron microscopy(SEM), transmission electron microscopy(TEM), and tensile tests. The effects of different fiber and calcination temperatures on the microstructures and properties of Al₂O₃-SiO₂ composite aerogels were investigated. The test results indicate that the mechanical properties of the aerogels are improved by introducing quartz filament fabrics and the introduction of alumina coating improves the thermal stability of the material. Compared to other fibers, Al₂O₃-coated hollow quartz fiber has significant advantages as reinforcement for composite, and their tensile strength is well retained after high temperature heat treatment.

An organic-inorganic hybrid sealing agent was fabricated and used in the plasma sprayed Al₂O₃-13 wt%TiO₂ coating, and conventional silicone agent was also used for comparison. Protection performance of the coatings was comprehensively evaluated based on both anti-corrosion and anti-biofouling properties. The results reveal that the sealing treatment is remarkably useful to decrease the porosity of the coating, and the porosity of the coating sealed with the hybrid agent is only 0.035%. Immersion corrosion test and Tafel polarization test reveal that the sealed coating with the hybrid agent exhibits a better corrosion resistance by compared with the coating sealed with silicone agent. The corrosion current density i _corr of the hybrid agent sealed coating is only 0.7 × 10⁻⁶ A·cm⁻². Moreover, anti-biofouling tests both in the outdoor analogue hydraulic environment and in the natural marine environment prove that the mentioned novel coating presents a better combination of corrosion resistance and anti-biofouling property by compared with the other coatings, and it could be used as a protection of metal components in the marine environment.

A green, renewable composite was designed and fabricated based on self-assembly of cyclodextrin metal-organic framework (CD-MOF) on graphene oxide(GO). Then, the GO@CD-MOF was embedded in 0.45 µm PTFE membrane to produce a dual-functional membrane which could carry out sample enrichment by capturing naringin molecules. The membrane filter was further improved by investigating the effects of the experimental parameters including amount of GO@CD-MOF, enrichment time and elution solvent on enrichment efficiency of naringin. Further, the present method had been successfully applied to citrus sample and obtained satisfied recovery value (79.7%–100.3%). Moreover, the extraction of naringin can be achieved for 2 min, and GO@CD-MOF loaded membrane can be reused at least for 5 times. The results demonstrate that the fabrication of the novel filter membrane based on GO@CD-MOF is a fast, simple and reliable, and possesses great potential in the determination of naringin from real samples by dual-function of separation and enrichment.

The thermal reduction of graphene oxide (GO) was performed by a tube furnace at different temperatures, and its structure evolution was investigated in detail. The results showed that the oxygen-containing functional groups on the carbon plane surface of GO gradually decomposed as the temperature increase, and the reduced graphene oxide (rGO) powder was obtained at 800 °C. Then, rGO powder was sintered under 30 MPa at 1 800 °C using spark plasma sintering (SPS) and hot-pressing (HP) to evaluate its structural stability at high temperatures. The defect densities of rGO were reduced after high-temperature sintering. The edge flatness and sp ² hybrid carbon plane structure were reconstructed effectively. These results demonstrate that the lamellar structure of rGO maintains the structural integrity during high-temperature sintering without obvious deterioration, which provides experimental and theoretical supports for GO reinforced ceramics.

A green and convenient pathway of preparing iron nanoparticles (FeNPs) with pomegranate leaf (PG) extract for highly effective removal of malachite green (MG) was proposed under ambient conditions. The materials were characterized by scanning electron microscope (SEM), X-ray energy-dispersive spectrometer (EDS), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) techniques. The results show that their surfaces are capped and stabilized by PG extract with amorphous nature and without any detection of zero-valent iron. The size and surface valence state of FeNPs are the key factors that affect the MG removal efficiency. As the reagent volume ratio of PG extract to FeCl₃ increases greater than 1, the cross-linked FeNPs become more obvious, having a homogeneous distribution with the size range from 30 to 40 nm, and show an increasing ratio of Fe(II)/Fe(III), which is in proportion to the degradation efficiency of MG, reaching higher than 95% in only 2 min by using 50 mg Fe/L FeNPs and 200 mg/L MG.

Nitrogen(N)-doped carbon nanosheets(TCM-900) were prepared by pyrolyzing the cobalt metal organic framework(MOF) and acid treatment. The TCM-900 showed outstanding ORR performance with half-potential of 0.805 V. The density function theory(DFT) reveals the nitrogen activates the carbon atoms in the framework. The homemade ZAB with TCM-900 as ORR electrocatalyst exhibits high-power density of 45 mW·cm⁻² and excellent long recharge cycling stability compared to Pt/C at 10 mA·cm⁻². This work illustrates an attractive future of the rechargeable ZAB.

Carbon black and Cr₂AlC were used as raw materials to obtain a large number of Cr₃C₂ nanosheets by means of the molten salt heat treatment at 1 100 °C for 1.5 hours. Results showed that carbon black can promote the decomposition of a large number of Cr₂AlC to form Cr₃C₂ and Cr₇C₃ nanoparticles at 1 100 °C in the absence of molten salt. Under a molten salt environment, carbon black can promote the complete decomposition of Cr₂AlC to form Cr₃C₂ and Cr₇C₃ nanosheets. The thickness of chromium carbide nanosheets is approximately 10–20 nm, and the length is approximately 100–200 nm. The addition of excess carbon black can promote the complete decomposition of Cr₂AlC into a material with Cr₃C₂ as the main phase.

Long-lasting constant loading commonly exists in silicon-based microelectronic contact and can lead to the appearance of plastic deformation. Stress relaxation behaviors of monocrystalline silicon coated with amorphous SiO₂ film during nanoindentation are probed using molecular dynamics simulation by varying the indenter’s size. The results show that the indentation force (stress) declines sharply at the initial and decreases almost linearly toward the end of holding for tested samples. The amount of stress relaxation of SiO₂/Si samples indented with different indenters during holding increases with growing indenter size, and the corresponding plastic deformation characteristics are carefully analyzed. The deformation mechanism for confined amorphous SiO₂ film is depicted based on the amorphous plasticity theories, revealing that the more activated shear transformation zones(STZs) and free volume within indented SiO₂ film promote stress relaxation. The phase transformation takes place to monocrystalline silicon, the generated atoms of Si-II and bct-5 phases within monocrystalline silicon substrate during holding are much higher than those for smaller indenter.

Li₂O−Al₂O₃−SiO₂ (LAS) glass-ceramics were prepared by a melting method. Effects of different Al₂O₃ content on the structure, crystallization, transmittance and fracture toughness of LAS glass-ceramics were investigated by means of XRD, FESEM and other methods as well. The results showed that the glass transition temperature and crystallization temperature of samples increased as the content of Al₂O₃ increased from 4.1 wt% to 13.1 wt%, which restrained the precipitation of lithium disilicate crystals. The main crystalline phase of glass-ceramics transformed from lithium disilicate and petalite to silicon dioxide, which reduced the fracture toughness of glass-ceramics. When the Al₂O₃ content was 7.1 wt%, the specimen had outstanding transmittance and fracture toughness. The transmittance was 90.32%. The fracture toughness was 1.13 MPa · m^1/2. Compared with high-alumina glass, the fracture toughness of the glass-ceramic was greatly improved, and it could be used as a new type of protective material for mobile devices.

A new raw material was developed for the preparation of dense (K, Na)NbO₃ (KNN) ceramics. In the absence of dopants, two kinds of KNN powder, calcined and microcrystalline powder, were used as matrix and seed to construct a duplex grain structure. The former was synthesized by the traditional solid phase reaction method and the latter by molten salt method. The effects of microcrystalline powder content on sintering behavior, microstructure and electric properties were investigated. It was found that appropriate microcrystalline powder content (x=0.4) promoted the grain growth and the gas diffusion, which resulted in a denser duplex grain structure and obtained a wide sintering temperature range. This work gives a basic raw material system for the development of high performance KNN ceramics. In addition, it also provides a new way to prepare dense ceramics by the design of a duplex structure.

Nd³⁺-doped NaGdF₄: Yb, Tm nanocrystals were synthesized by an improved high-temperature thermal decomposition method, and the effects of doping concentrations on the crystal structure, phase composition, and upconverted fluorescence intensity were also investigated. The results reveal that the introduction of Nd³⁺ ions does not cause the transformation of the crystal phase, but induce the change of the unit cell parameters. Meanwhile, the fluorescence intensity of the synthesized nanocrystals when co-doped with 3 mol% Nd³⁺ is the strongest under the excitation of 980 nm laser, which is 3.9 times that of the Nd³⁺-free doped nanoparticles, and the average size is 62.9 nm. And it is located in the blue area of the CIE coordinate diagram, and the corresponding color purity is 91.81% under the same experimental conditions. The resulting nanocrystals show the potential as excellent fluorescence labeling and in vivo imaging probes.

The purpose of this study is to apply the steel coated by cement paste to evaluate the corrosion inhibition of NO₂ ⁻ intercalated Mg-Al layered double hydroxides (LDHs), which was prepared by a conventional calcination-rehydration method. The chloride equilibrium isotherm, open-circuit potential (OCP) and electrochemical impedance spectroscopy (EIS) of steel in the saturated Ca(OH)₂ solution contaminated by chloride ions were measured. The microstructures of as-obtained LDHs and cement paste containing the LDHs were observed by scanning electron microscope (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and mercury intrusion porosimetry (MIP). It is found that the technique using the steel coated by the cement paste layer containing the LDHs to represent the steel in real concrete can be applied to accurately evaluate the corrosion inhibition performance of NO₂ ⁻ intercalated LDHs in a short duration. The addition of NO₂ ⁻ intercalated Mg-Al LDHs can improve the absorption capacity of Cl⁻ and the anti-corrosion property of cement paste layer. The combination actions of the refinement of pore structure, uptake of chloride ions and release of inhibitive NO₂ ⁻ contribute to the better corrosion protection property of cement paste layer. Moreover, a schematic mechanism of chloride intrusion for the steel specimen with cement paste layer is developed.

The abrasion resistance of cement pastes with 30 wt%, 40 wt% and 50 wt% granulated blast furnace slag (GBFS), and its relations to microhardness and microstructure like hydration products and pore structure were studied. Results indicated that GBFS decreased the abrasion resistance of paste, and among the pastes with GBFS, the paste with 40 wt% GBFS showed the highest abrasion resistance. The microhardness of GBFS was lower than that of the cement, and the microhardness of the hydration products in paste with GBFS was also lower than that of the hydration products in paste without GBFS, so that the abrasion resistance of paste decreased when GBFS was incorporated. The reason for the decrease of microhardness of pastes with GBFS was that the contents of Ca(OH)₂ in pastes with GBFS was significantly lower than that in the paste without GBFS, while large amounts of calcium aluminate hydrates and hydrotalcite-like phases (HT) in pastes with GBFS were generated. Furthermore, among the pastes with GBFS, the paste with 40 wt% GBFS showed the lowest porosity which was the main reason for its highest abrasion resistance.

Efforts have been made to evaluate the influences of the addition of nanoparticles on the strength, durability and mineralogical changes of high strength concrete (HSC). Therefore, mixes were prepared for conventional concrete mix (CCM) of M80 grade. Further, various mixes were prepared by replacing cementitious materials initially with 1% Nano-CaCO₃ (NC), 2% NC, 3% NC in the CCM, and then 1% NC and Nano-SiO₂ (NS) NS, 2% NC and NS, 3% NC and NS (NC and NS were in equal proportion) in the CCM. The developed concretes were then evaluated for mechanical properties, permeation characteristics, and mineralogical studies. From the studies, it is found that the concrete at 2% NCS possesses superior mechanical and superior permeation characteristics of all the mixes. A clear variation in the mineralogical structure with the addition of nanoparticles has been observed.

A cermet composite was prepared by employing thermal spraying flame onto stainless steel surfaces of (304) type. Hence 25,50% of aluminum was mixed with matrix of (10% Al₂O₃- SiO₂). A spray system consistis of oxygen barrel, acetylene and spray gun that contains powders feeder at different spray distances (5, 10, 15, 20 and 25 cm). The thermal treatment of the samples resulting from spraying was performed at 1 100 °C for 1.5 hr. Some physical examinations (porosity and adhesion), mechanical tests (hardness and wear rate) and Atomic Force Microscope (AFM) test were performed before and after thermal treatment. The test results showed that the best mixing rate was (50%) and the best spray distance was (15cm) where the quality of coating layer improved after thermal treatment at 1 100 °C for 1.5 hr with a porosity ratio reduced from 11.2% to 6.6%, and adhesion strength improved with the increase in the alumina content to 50%. The results demonstrated that the best adhesion value after thermal treatment was 30.98 MPa. The hardness of coating layer increased from 45.78 to 54.88 HV; while the lowest rate of wear was at 50% of alumina with a spray distance of 15cm. Also, there was a clear improvement based on AFM within grain size, root mean square and roughness rate.

To analyse the self-healing capacities in terms of mechanical performance of the pozzolanic materials, such as, fly ash, metakaolin and silica fume and crystalline admixtures. Pre-cracked concrete cubes with about 0.05 mm width were exposed to four different environmental conditions at different exposure times in order to determine the effect of temperature and water availability on the self-healing potential. After the exposure, the control and tested concrete cubes were evaluated for regained strength, void reduction, corrosion inhibition, damp proofing, relative impermeability and durability. The samples with SF10CA have better cementitious filling and low percentage of voids and water absorption.

Cement used in severe maritime environments must be attached with exceptional properties such as high sulfate resistance and abrasion strength. A sulfate resistant material typically used in marine engineering is high ferrite cement, which has been utilized in sulfate-rich environments. This study aims at exploring the effect of C₄AF and heat-curing on the abrasion resistance of high ferrite cement (HFC, C₄AF: 14%–22%) in order to have a comprehensive understanding of this mechanism and promote the application of HFC in marine engineering. A new invention was designed for the abrasion resistance device by considering the sea-wave abrasion and seawater erosion in laboratory. The compressive strength and abrasion resistance of HFC were measured. Additionally, advanced analytical methods were used to explore the abrasion resistance mechanism of HFC, including X-ray fluorescence (XRF), X-ray diffraction (XRD), and thermogravimetric (TG) analyses, as well as mercury intrusion porosimetry (MIP). The results showed that HFC had the best abrasion resistance under appropriate heat-curing system that the curing temperature was 50 °C and the hosting time was 4 hours, compared with PI (Portland cement) and LHC (low heat cement), meanwhile the abrasion resistance of HFC had a 62.4% increase when C₄AF content is increased from 14% to 22%. It can be ascribed that the content of portlandite is decreased due to the increase of C₄AF, which can reduce the portlandite assembled in ITZ (interfacial transition zone). It can also be ascribed that the DEF (delayed ettringite formation) is successfully avoided in HFC and the hydration degree of HFC can continue to be boosted under appropriate heat-curing system.

In order to adapt to the high temperature and heavy load process environment of large forgings, a novel die with “fist-like” structure is designed. The “fist-like” die mainly consists of “skin” layer, “bone” layer and matrix. To obtain the material with good supportability and good bonding strength with the “skin” layer, iron-based alloys RMD248 and CN72 were selected to make the “bone” layer, and the properties were compared. In this paper, the “bone” layer and the “skin” layer (CHN327) were surfaced on 5CrNiMo matrix by wire arc additive manufacture (WAAM). Then, cyclic heating to 500 °C and thermal compression with a maximum deformation of 30% were adapted to test the high temperature mechanical properties. The microstructure changes before and after thermal cycles and compressions were observed by optical microscopy (OM), X-ray diffraction (XRD), energy dispersive spectrometer (EDS) and scanning electron microscopy (SEM). The results show that CN72 has more carbides than RMD248 at the joint surface, which makes it easy to form brittle fracture at the joint. Mechanical properties were tested by using microhardness machine. Meanwhile, hot tensile tests were performed to study bonding strength between the “skin” layer and the “bone” layer. The results show that the RMD248 has stable microhardness distribution while the microhardness of CN72 decreases with the distance from the interface. And the ultimate tensile strength between CN72 and CHN327 is higher than RMD248 in the temperature range of 400–450 °C. It can be inferred that CN72 has higher inter-layer wear resistance and RMD248 has more stable high temperature performance.

The effects of the solution treatment on the microstructure, recrystallization, texture composition and properties of 7A65-T7451 (120 mm) hot rolled plates at H/2 (1/2 thickness) and H/4 (1/4 thickness) were studied. The results show that the hot rolled microstructure mainly contains a large amount of MgZn₂ phases and minor Al₇Cu₂Fe phase. After solid solution treatments, a large amount of MgZn₂ phases are dissolved back into the aluminum matrix. The main texture types at H/4 are R-Cube, Cube and part of Brass texture, and the main texture types at H/2 are Cube, R, and Copper texture. The qualitative analysis by Schmidt’s law reveals that Copper texture at H/2 will deepen the anisotropy of plate metal properties. For the plate with the same thickness, the two-stage solution state has better mechanical properties due to the lower degree of recrystallization and stronger grain boundary strengthening effects. Under the two-stage solution system of 460 °C/165 min+477 °C/165 min, the composite mechanical properties of the alloy plate at H/4 are the best and the anisotropy is not obvious. The tensile strength, yield strength, and elongation along the rolling direction are 561.9 MPa, 523.4 MPa, and 10.6%, respectively..

Ti-47Al alloy was fabricated by multi-physical fields activated sintering technology (FAST). With the coupling effects of electrical and pressure fields as the dominant driving force, a nearly full-density (relative density: 99.15%) TiAl alloy sample was obtained. The microstructural characterizations, phase transformation at different sintering temperatures and their contributions to mechanical properties were investigated. The results reveal that TiAl₃ is the main phase when sintered at 600 and 700 °C. When the sintering temperature reaches 800 °C, the main phases are TiAl and Ti₃Al. With the increase of sintering temperature, the content of TiAl increases and that of Ti₃Al decreases. When the sintering temperature reaches 1 000 °C, the alloy with fine and uniform microstructure and good mechanical properties can be obtained.

Steel slag contains a large amount of calcium silicate, which can react with CO₂ to generate CaCO₃ and SiO₂ colloid, thus steel slag may become a cementitious material with a certain strength. High strength porous steel slag carbonated brick was prepared by adding easily decomposed bicarbonate solid into steel slag as pore-forming agent and then accelerating carbonation. A variety of characterization methods were used to characterize the composition and micro-structure of the samples. The effects of different pore-forming agent dosage and carbonation time on the properties of pore steel slag blocks were discussed. The results show that the addition of ammonia bicarbonate promotes the nucleation and growth of columnar calcite. The strength of steel slag block mixed with 30% pore forming agent can reach 24.8 MPa after 1 day of carbonation, and then the strength development tends to slow down.

The corrosion behavior of formic acid towards bronze under thin electrolyte layer (TEL) was investigated by means of electrochemical measurement. Bare bronze had smaller self-corrosion current density than Cu₂O patina bronze and CuCl patina bronze, while it had higher polarization resistance. The corrosion behavior of bronze materials had differences in various TELs and bulk solutions. The critical thickness of TEL for Bare Bronze was 200 µm, which normly occurred in the transformation from anode control to cathode control. The thickness of TEL had a negligible effect on the corrosion rate of Cu₂O patina bronze when it was greater than 150 µm. For CuCl patina bronze, the corrosion process accelerated with thinner TEL. SEM was used to analyze the morphology and composition of corrosion products. Cu₂O,Cu(OH)(HCOO) and Cu(HCOO)₂ were formed on the surface of Bare Bronze and Cu₂O patina bronze, nevertheless, the main corrosion product of CuCl patina bronze was Cu₂Cl(OH)₃.

The flow stress behavior of GH4033 superalloy was determined by the hot compression tests at the temperatures of 1 223–1 473 K and the total strains of 0.6 with the strain rates of 0.001–30.0 s⁻¹ by using cylindrical samples. The processing maps based on the dynamic material model (DMM) combined with the corresponding microstructure observations indicate the reasonable processing domain locating at the strain rates of 0.1–1.0 s⁻¹ and the deformation temperature of 1 273–1 423 K. Meanwhile, the numerical simulation based on finite element model (FEM) described the variation of the effective strain, effective strain rate and the temperature for the core node, and unveiled the influence of the hot rolling parameters considering the initial temperature (T ₀) range of 1 223–1 473 K and the first-stand biting velocity (v ₀) range of 0.15–0.35 m·s⁻¹. Furthermore, the deformation stability of GH4033 superalloy in the round rod hot continuous rolling (HCR) process is described and analyzed by coupling the three-dimensional (3-D) processing map, and the spatial trajectory lines were determined by the numerically simulated temperatures, the strains and the strain rates. Finally, the results show that the hot deformation stability of GH4033 can be achieved by the rolling process parameters located at T ₀=1 423 K and v ₀=0.25 m·s⁻¹. Additionally, the practical HCR processes as T ₀=1 423 K and v ₀=0.15, 0.25, 0.35 m·s⁻¹ were operated to verify the influence of the hot rolling parameters on the hot deformation stability by the microstructure observation of the final products.

A hypereutectic Al-50 wt%Si alloy for electronic packaging was prepared by spark plasma sintering (SPS) technology using gas-atomized Al-50 wt%Si powder. The effect of sintering parameters on alloy phase composition, microstructure, thermal performance and the tensile strength at different temperatures was investigated. The experimental results show that the alloy can obey the diffraction peaks of silicon and aluminum without other peaks appearing. The primary silicon in the prepared alloy can be evenly distributed in the aluminum matrix. The coefficient of thermal expansion (CTE) and thermal conductivity (TC) of the alloy will improve with the increase of sintering temperature, but they will decrease after sintering for a long time, which is caused by the large difference of coefficient of thermal expansion between silicon and aluminum. The tensile properties of the alloy at room temperature will increase with the increase of sintering temperature, but higher test temperatures will inhibit the tensile properties except the elongation. The morphology and fracture mode of the tensile fracture are also analyzed to determine the good bonding strength of the alloy.

The fatigue crack behavior of U75V rail under different quenching rates was studied using SEM and CLSM. The results show that the pearlite interlayer spacing and fatigue crack growth rate decrease, and the deflection path of cracks and the number of branching cracks of U75V rail increases with an increase of cooling rate. The tearing edge of unstable region transites from pearlite lamellae to dimple. The fatigue crack growth path is closely related to the orientation of lamellae in pearlite microstructure. There are three modes direction of fatigue crack growth path and pearlite lamellar, which are parallel, vertical and 45° angle, and most of the branch cracks occur at an angle of 45 ° between the lamellar direction and the crack direction. More specifically, the deflection paths of cracks and branching crack have a relaxation effect on the stress intensity at the crack tip, which restrains the fatigue crack growth rate.

The hot-plate rolling (HPR) process is adopted to achieve the optimal strength-ductility for the in-situ nano-TiC_P/Al-Mg-Si composites. There was no crack in the sheet by single pass of hot-plate rolling with a thickness reduction of 80%, while there were numerous cracks in the sheet by two passes of conventional hot rolling to achieve a total reduction of 50%. The microstructure and mechanical properties of the composites subjected to 80% thickness reduction of hot rolling at 540 °C were investigated by tensile tests, scanning electron microscopy, and electron backscatter diffraction. The yield strength and ultimate tensile strength of in-situ nano-TiC_P/Al-Mg-Si composites after the hot-plate rolling process and T6 heat treatment increased significantly due to the dislocation strengthening and precipitation strengthening.

The hollow cylinders of TiB-Ti composites with a gradient distribution of Ti phase were synthesized by the combination of traditional slurry spray with centrifugal forming process. The influences of the concentration of sodium hexametaphosphate (SHMP), the concentration of polyvinyl alcohol (PVA) and solid content (20 vol%–35 vol%) on the rheological properties of the TiB₂−Ti composite slurries were investigated. Slurries with low viscosity, weak thixotropy and shear-thinning behaviour were obtained for facilitating the slurry spraying process. The effects of different centrifugal conditions on the migration of components during the forming process were studied. The phase composition and the elements distribution of the prepared samples were characterized by the energy-dispersive X-ray spectrometer. The observations revealed that the samples fabricated at 1 500 r/min for 3 min had a significant composition variation. For two-phase systems with small density differences and large particle size variation, centrifugal time was more important than centrifugal speed in forming a continuous gradient structure.

Trimethoxysilyl Polyester (TMOS-PET) was prepared via hydrosilylation of trimethylsilane with acryl-terminated polyester. Copolymerization of TMOS-PET with trimethylmethoxysilane, tetramethoxysilane, and/or dimethyldimethoxysilane give silicone modified polyesters (Si-PET) containing =(SiO₂)=, −(CH₃SiO_3/2)=, and/or −((CH₃)₂SiO)- units. Coatings from Si-PET were formed on tinplate surface via room temperature vulcanization with applicable curing time (the quickest tact free time and completely drying time are 2 h and 15 h, respectively). Mechanical properties, thermal stability, chemical resistance, and anti-corrosion of coatings were detected. Although the flexibility of the coatings were lowered by =(SiO₂)= and -(CH₃SiO_3/2)= units, adhesion and thermal stability of coatings were both improved. On the contrary, (CH₃)₂SiO- units seem to improve the flexibility, while decrease the adhesive force for less crosslink points. Generally, the silicone modified polyesters act as an effective shielding for tinplate. According to electrochemical impedance spectroscopy (EIS), the electric resistance of coatings (Rc) were improved about 25 times and open circuit potential (OCP) increased about 0.10 V compared to the control. The chemical resistance and anti-corrosion of the coatings were decreased slightly after =(SiO₂)= and -(CH₃SiO_3/2)= units were added, but they could be greatly improved by -(CH₃SiO_3/2)= units. Specially, after adding -(CH₃SiO_3/2)= units, coatings give doubled Rc, and its OCP is about 0.20 V higher than the control.

The flame-retardant properties of polyurethane (PU) containing ammonium polyphosphate (APP) and aluminum hydroxide (ATH) were investigated. Moreover, the flame retardant performance was investigated through thermogravimetric analysis, limiting oxygen index (LOI), vertical combustion (UL 94), and cone calorimeter. When 15 wt% APP and 5 wt% ATH were added together, the PU/15%APP/5%ATH sample shows better thermal stability and flame-retardant properties. When 15 wt% APP and 5 wt% ATH were added together, the LOI value of the PU/15%APP/5%ATH sample was 30.5%, and UL 94 V-0 rating was attained. Compared with PU, the peak heat release rate (PHRR), total heat release (THR), and average effective heat combustion (av-EHC) of the PU/15%APP/5%ATH sample decreased by 43.1%, 21.0%, and 29.4%, respectively. In addition, the flame-retardant mechanism was investigated through cone calorimeter. The APP/ATH addition simultaneously exerted condensed phase and gas phase flame retardant effects. APP and ATH have synergistic flame retardant properties.

Due to the multiformity and complexity of chain conformation under external flow and the challenge of systematically investigating the transient conformation and dynamic evolution process of polymer chains at the molecular level by means of present experimental techniques, a universal description of both chain conformation and dynamics with respect to continuous volume extensional flow (CVEF) is still absent. Taking into account the temperature effect, we performed dissipative particle dynamics (DPD) simulations with the particles corresponding to the repeat units of polymers over a wide temperature range and analyzed the correlation with the conformational properties of ultra-high molecular weight polyethylene/polypropylene (UHMWPE/PP) blend in response to the CVEF. With time evolution, the polymer chains become highly oriented parallel to the flow direction instead of the initial random coiling and self-aggregation. It is found that a high temperature is necessary for more substantial compactness to take place than low temperature. The low-k plateau and low-k peak in structure factor S(k) curves suggest a low degree of conformational diversity and a high degree of chain stretching. It is also concluded that the intra-molecular C-C bond interaction is the main driving force for the dynamics process of the chain conformations undergoing CVEF, where the motion of the alkyl chains is seriously restricted owing to the increase in bond interaction potential, resulting in a reduction of the difference in diffusion rates among alkyl chains..