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Summary Elevation in homocysteine (Hcy) level is associated with insulin resistance; however, the causality between them and the underlying mechanism remain elusive. Here, we show that Hcy induces insulin resistance and causes diabetic phenotypes by protein cysteine-homocysteinylation (C-Hcy) of the pro-insulin receptor (pro-IR). Mechanistically, Hcy reacts and modifies cysteine-825 of pro-IR in the endoplasmic reticulum (ER) and abrogates the formation of the original disulfide bond. C-Hcy impairs the interaction between pro-IR and the Furin protease in the Golgi apparatus, thereby hindering the cleavage of pro-IR. In mice, an increase in Hcy level decreases the mature IR level in various tissues, thereby inducing insulin resistance and the type 2 diabetes phenotype. Furthermore, inhibition of C-Hcy in vivo and in vitro by overexpressing protein disulfide isomerase rescues the Hcy-induced phenotypes. In conclusion, C-Hcy in the ER can serve as a potential pharmacological target for developing drugs to prevent insulin resistance and increase insulin sensitivity.

As-cast Mg-3Er-xZn (x = 0, 0.5, 1 and 2 at.%) alloys were prepared by a cast ingot metallurgy process. The effect of Zn contents on the microstructure and phase constitution of the alloys was investigated by optical microscope (OM), scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and transmission electronic microscope (TEM). The results revealed that the as-cast Mg-3Er alloy mainly consisted of α-Mg phase and MgEr eutectic phase. Typically, a small amounts of LPSO phase was precipitated at grain boundaries by adding 0.5 at.% Zn into Mg-3Er alloy. With the addition of 1 at.%Zn, the volume fraction of LPSO phase increased obviously. When the addition of Zn increased to 2 at.%, the volume fraction of LPSO phase decreases and Mg8ZnEr phase forms at grain boundaries. Tensile test indicated that Mg-3Er-1Zn alloy exhibits the excellent mechanical properties. The tensile strength, yield strength and elongation of Mg-3Er-1Zn alloy are 213 MPa, 187.6 MPa and 5.52%, increased by 38.8%, 60% and 3.19%, respectively, corresponding to the alloy without Zn addition. The excellent mechanical properties could be attributed to the introduction of Zn element in alloys, which leads to the strengthening of LPSO phase and grain refinement of α-Mg.

In this paper, the liquid phase separation and solidification process of the Al75Bi9Sn16 immiscible alloy were studied with calorimetric and resistivity methods to make the melt superheated treatment process. The impact of melt overheating treatment (MOT) on the phase constitution and solidification microstructures were investigated using X-Ray diffraction (XRD) and field emission scanning electron microscope (FESEM) to determine the structural sensitivity to the melt superheated degree, and find a new strategy for improving the forming ability of the core-shell structure of the Al75Bi9Sn16 alloy. The results show that: the liquid phase separation and precipitation of primary (Sn) phase occur in 1039K-880K and 460K-403K; the core-shell structure with Sn-Bi-rich core and Al-rich shell can be formed under conventional casting conditions; the melt overheating treatment (MOT) can promote the formation of core-shell structure by increasing solidification time t0 and decreasing the average solidification rate v.

A new surface molecularly imprinted polymer (MIP) based on nano-TiO2 was developed using propazine (Pro) as a template molecule, ethyleneglycol dimethacrylate (EGDMA) as a crosslinker, methacrylic acid (MAA) as a functional monomer, and 2,2'-azobis (isobutyronitrile) (AIBN) as an initiator. Structures of the newly synthesized surface MIPs were characterized by Fourier transmission infrared spectrometry (FT-IR), scanning electron microscope (SEM), transmission electron microscope (TEM), and X-ray diffraction (XRD). The MIP had a good adsorption capacity and high recognition selectivity to propazine. Meanwhile, it exhibited a cross-selectivity for simazine (Sim) and atrazine (Atr). The MIPs were used as a solid phase extraction (SPE) material. Concomitant extraction, purification, and determination of three pesticides (Pro, Sim, and Atr) residues in water, soil, and maize plant and grain samples were performed by MIP-SPE coupled with high performance liquid chromatography (HPLC). The highly selective separation and enrichment of Pro, Atr, and Sim from the complex environmental media can be achieved. Thus, the newly developed technique provides an analytical platform to quantify the trace amount of Pro, Sim, and Atr residues in multi environmental media and food source.

Metal matrix composites reinforced by graphene particles exhibit physical and mechanical property and are developed and qualified for use in aerospace structure, bioengineering, energy storage material and photoelectric device. In the present paper, graphene was fabricated by modify Hummers method, and then was surface modified by chemical plating copper. The graphene/Al composites were fabricated by powder metallurgic method. Morphology characterization of graphene and composites were detected by XRD and SEM,the fabrication parameters of composites were optimized by testing harness and density. The volume fraction of graphene particles was 3%, the density of composites was maximum of 96.5%. The hardness had a maximum of HB 42.6, and the hardness of graphene/Al composites increased by 33.5%.

We present a new Al-Cu-Mn system to fabricate nanoporous copper ribbons by dealloying. The microstructures of the nanoporous copper ribbons are characterized using X-ray diffraction, scanning electron microscopy and energy dispersive X-ray analysis. The results show that the compositions of the melt-spun Al-Cu-Mn alloys have an important effect on the dealloying process and microstructures of the nanoporous copper ribbons. The melt-spun Cu30Al40Mn30, Cu30Al35Mn35, Cu30Al30Mn40 and Cu30Al25Mn45 (at.%) alloys can completely form a bicontinuous interpenetrating ligament-channel structure. Compared with other alloys, the dealloying of Cu30Al40Mn30 alloys is more difficult. In addition, for Cu30Al35Mn35 and Cu30Al30Mn40 alloys, porous structures are relatively uniform. But for the Cu30Al25Mn45 alloys, porous structure is not uniform, occurring aggregation phenomenon.

This article reports the effect of MnCO3addition on the grain refinement efficiency of AZ91 magnesium alloy. The results indicate that the addition of MnCO3has excellent grain refining efficiency for AZ91 alloy, which is mainly attributed to the Al4C3particles formed in the melt, besides Mn is indispensable to grain refinement in Al-bearing magnesium alloys. There is an optimal addition amount of 0.6% at 740 °C and the grain size is reduced from 245 to 91 μm. At the same time, the corrosion resistance performance of MnCO3-added AZ91is improved.

In this paper, Al/WC composite coatings on A356 alloy were prepared by mechanical alloying, and their mechanical properties were characterized. The processing parameters for mechanical milling treatment, such as the premixing process of Al and WC powders, the ball-to-powder weight ratio and the milling duration, have been optimized, and the optimum ball-to-powder weight ratio and milling time were determined to be 14:1 and 12 h, respectively. It was found that premixed Al and WC powders have no significant influence on Brinell hardness due to the powders adhering to the balls and milling tank wall. With the Al/WC composite coating, the Brinell hardness of A356 alloys can be significantly improved from 65 HBW to 115 HBW.

In order to prevent the sublimation of Sb, protective Mo coatings were deposited on the CoSb3 substrate by DC magnetron sputtering. Thermal aging behavior of CoSb3 with Mo coating was investigated by accelerated experiment at 650oC for 24h. The results indicated that Mo coatings exhibit columnar crystal and body-centered cubic structure. It was found that the weight loss decreases with the increasing thickness of Mo coating. In comparison with naked CoSb3 material, the degradation of thermoelectric properties of CoSb3 with Mo coatings decreases under accelerated thermal aging test.

The effects of Al-P addition on the microstructure and mechanical properties of as-cast Mg-5%Sn-1.25%Si magnesium alloy were investigated. The results show that the phases of the as-cast alloy are composed of α-Mg, Mg2Sn, Mg2Si, little P, and AlP. The Chinese character shape Mg2Si phase changes into a granular morphology by P addition because AlP can act as a heterogeneous nucleation core for the Mg2Si phase. When 0.225wt% of Al-3.5%P alloy is added, the mechanical properties of the Mg-5%Sn-1.25%Si alloy are greatly improved, and the tensile strength increases from 156 to 191 MPa, an increase of 22.4% compared to the alloy without P addition. When the amount of Al-3.5%P reaches 0.300wt%, a segregation phenomenon occurs in the granular Mg2Si phase, and the tensile strength and hardness decrease though the elongation increases.

A new molecularly imprinted polymer (MIP) based on silica-gel surface was developed using Dufulin (Duf) as a template, methacrylic acid (MAA) as a functional monomer, ethyleneglycol dimethacrylate (EGDMA) as a crosslinker, and azodiisobutyronitrile (AIBN) as an initiator. The synthetic samples were characterized by the techniques of Fourier transmission infrared spectrometry (FT-IR) and scanning electron microscope (SEM). Batch experiments were performed to evaluate adsorption isotherms, adsorption kinetics and selective recognition of the MIP. Binding experiments demonstrated that the MIP had a good adsorption capacity, fast mass transfer rate and high recognition selectivity to Dufulin. When the MIP was used as a solid-phase extraction (SPE) material, the recoveries of Dufulin for spiked water, soil and wheat samples were 88.98-102.16%, 85.31-99.57% and 87.84-100.19%, along with LOD of 0.0008 mg L(-1), 0.010 mg kg(-1) and 0.023 mg kg(-1), respectively. Compared with direct determination of HPLC without MIP-SPE, the highly selective separation and enrichment of Dufulin from the complex environmental media can be achieved by the newly developed molecular imprinting at the surface of silica gel.

In this study, hypoeutectic Al-Si casting alloy was investigated to obtain high strength, according to alloying of Cu Mg, refining of Al-5Ti-B master alloy, modifing of Re and T6 heat treatment. The experimental results show that the mechanical properties of the tested alloy reach peak when addition of Al-5Ti-1B alloy is 1.0% after heat treatment, especially the yield strength, correspondingly, microstructure distribution gets to the best state. When Al-5Ti-1B exceeds 1.0%, the mechanical properties descend gradually. The metallic compounds of Mg2Si phase, CuA12 phase and W phase precipitated along the grain boundary and strengthened dispersively can improve mechanical properties of the tested alloys. The yield strength of samples added 0.1% Re (La 50%, Ce 40%) increases slightly, simultaneously, the tensile strength and elongation decreases. After 0.1% Re, the mechanical properties get down.

Aluminum Borate Whisker/Aluminum Phosphates composites (ABW/AP) added Si3N4were prepared with pressure sintering technique. The influence of Si3N4on the mechanical properties and dielectric properties were investigated. After sintered at 1050°C for 1h, the results showed that the flexural strength of the composites with 5wt% Si3N4addition reach 167.29MPa,the dielectric constant (ε) and loss tangent (tanδ) of the composites are 2.99 and 0.0089 at 10GHz. The testing results was discussed.

The copper based electric contact materials with multicomponent substance were obtained by powder metallurgy. The hardness and density of the samples increase with adding proper amount of Y 2 O 3 . Adding 1.5 wt.% Y 2 O 3 the hardness of the sample reaches the maxim and the density of sample reaches the maximum by adding 2 wt.% Y 2 O 3 . In this paper, the effects of addition of Y 2 O 3 on the performance of copper based contact materials were studied by metallographic microscope, XRD, SEM in details. Moreover, the mechanism of the effects was discussed.

The microstructure, hardness and corrosion resistance of AZ91D alloy were investigated under different solution treatments and artificial aging conditions.When ascast AZ91D alloy was heat treated at 415°C by solution treatmentfor 12 h and artificially aged at 200°C, the volume fraction of precipitates increased with the aging time up to 10 h.When ascast AZ91D alloy was treated at 430°C by solution treatment for 12 h and artificially aged at 200°C for 10h, the volume fraction of precipitates reached a peak value.The results of the corrosion test showed that a high corrosion resisting of the second phase precipitates was beneficial to improving the strength and hardness. Solution treatment at 445°C temperature for 12 h destroied the consecutiveness of β-Mg17Al12 phases.

Magnesium alloys are becoming ever more prevalent in automotive and aerospace industries as energy conservation and performance demands increase. However, it is limited on further application in the automotive field for its low strength compared with steel and aluminum alloys. Effects of Si addition on microstructure and mechanical properties of as-cast Mg-5%Sn magnesium alloy were also studied using SEM, XRD and tensile testing. The results show that the phases of as-cast alloy are composed of α-Mg, Mg2Sn; Mg2Si. The addition of Si suppresses the precipitation of the Mg2Sn, Product Chinese character shape phases of Mg2Si. With the increase of Si content, the effect becomes more apparent. When Si content is up to 1.25wt%, the grain refining effect reached best level. The average alloy grain size reduced from 90μm to 30μm, the tensile strength is the highest. The average tensile strength increased from 128 MPa to 156 MPa. When the Si added at 1.25wt% or less, the hardness and strength were improved with the increase of Si. When 1.25% Si was added, grain did not become further refinement. While Si content was continue to be increase, the tensile strength decreased.

Chemical membrane coating method was adopted for AZ91 magnesium alloy surface to explore the preparation method for cerium (Ce) conversion membrane, lanthanum (La) conversion membrane and double rare earth conversion membrane. The methods such as Scanning Electron Microscope (SEM), Energy Spectrometer (EDS) and X-ray Crystallography (XRD) were introduced for the detection of conversion membrane. The experiment results revealed that the corrosion resistance of double rare earth conversion membrane would get strengthened firstly, and degraded later along with the prolongation of conversion time. The corrosion resistance from low to high of conversion membrane is cerium (Ce) conversion membrane < lanthanum (La) conversion membrane < double rare earth conversion membrane. Therefore, double rare earth conversion membrane is more effective to improve the corrosion resistance for magnesium alloy and its corrosion resistance is better than that of single rare earth conversion membrane.

In this paper, Al-12.6%Si/Al63Cu25Fe12 composites were fabricated by method of casting. The microstructure and chemical composition of Al63Cu25Fe12 quasicrystal alloy and Al-12.6%Si alloy reinforced by the quasicrystal were studied, and the mechanical properties of Al-12.6%Si composite were also measured. The results show that almost single quasicrystalline phases exist in the samples which are cast with the 1300°C melt. Quickly enough cooling rate and appropriate melt temperature are necessary for the formation of the quasicrystalline phase. In addition, Al-12.6%Si composite has optimal mechanical properties when the amount of Al63Cu25Fe12 quasicrystal is 3 wt%.

Cu-38Zn thin film (wt %) was deposited on the unheated microscope glass at the nanometer scale by DC magnetron sputtering. Subsequently, the nanocrystalline films were dealloyed in H2SO4 aqueous solution etching of zinc component, resulting in the formation of nanoscale porous copper film with average porous diameter of approximately 94 nm. The films microstructure and element composition were characterized by X-ray diffraction and scanning electron microscopy. The experimental results show that Cu-38Zn films are quasi-amorphous structure, porous copper film with different porous sizes is prepared by selective dissolution of zinc atoms from a nanocrystalline dual-phase film under free corrosion conditions, the grain size of the Cu-Zn films has an important effect on the dealloying process and the microstructures of the nanoscale copper films.

Effects of AlN addition on the microstructure and mechanical properties of as-cast Mg-Al-Zn magnesium alloy were investigated using optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and tensile testing. Five different samples were made with different amounts of AlN(0wt%, 0.12wt%, 0.30wt%, 0.48wt%, 0. 60wt%). The results show that the phases of as-cast alloy are composed of α-Mg,β-Mg17Al12. The addition of AlN suppressed the precipitation of the β-phase. And, with the increase of AlN content, the microstructure of β-phase was changed from the reticulum to fine grains. When AlN content was up to 0.48wt% in the alloy, the β-phase became most uniform distribution. After adding 0.3wt% AlN to Al-Mg-Zn alloy, the average alloy grain size reduced from 102μm to 35μm ,the tensile strength of alloy was the highest. The average tensile strength increased from 139MPa to 169.91MPa, the hardness increased from 77.7HB to 98.4HB, but the elongation changes indistinctively. However, when more amount of AlN was added, the average alloy grain size did not reduce sequentially and increased to 50μm by adding 0.6wt% AlN and the β-phase became a little more. Keywords: Al-Mg-Zn alloy; AlN; β-Mg17Al12; Tensile strength

Fractal analysis based on results of high temperature X-ray diffraction experiment was used to study the temporal-spatial properties of particles in In-40wt.%Sn melt. Partially-overlapping multirange fractal structure is observed in In-40wt.%Sn melt, and as temperature decreases from 800°C to 130°C, low fractal dimension was found to range between 2.000 and 2.669, high fractal dimension is still 3.000 without alteration. Moreover, low fractal dimension reveals a discontinuous change between 600°C and 700°C. Fractal characteristics of In-40wt.%Sn melt were correlated with the evolution of microstructure. The discussion was made in detail. Multirange fractal model was proposed to calculate transition region curves of multirange fractals. The results show that values of simulation show good agreement with experimental values, the maximum error is less than 1.3%. From the analysis, the range of the transition region between two fractal regions is speculated to be related with structure properties of metal melts. In addition, ultrafine particles’ aggregation mechanism was used to analyze the fractal morphologies. Keywords: multirange fractal; In-40wt.%Sn melt; microstructure change; X-ray diffraction.

Microstructure and mechanical behaviors of AZ91 cast magnesium alloys with melt superheating and thermal rate treatment technique were studied. Alloy grains thicken at 820°C and refine at 870°C when they contains Mn element and the crucible had no coating on the internal surface. Moreover, the strengthening γ phase is more dispersive and uniform at 870°C. Thermal rate treatment significantly improved the microstructure, mechanical behaviors and casting quality of AZ91 alloy as microstructure of AZ91 alloy reserves some characteristics of the high temperature melt.

On the basis of measuring the electrical resistivity of Sn melt and referring to analysis of high temperature XRD, the change of electrical resistivity and structure for Sn melt with temperature was carried out. The results show that there is discontinuous change of electrical resistivity for Sn melt with the temperature in the metrical temperature range. There is a correlation between the electrical resistivity change and the structure change of Sn melt. The correlation radius and the fluid cluster size of Sn melt decrease with the increasing of temperature, so that the electrical resistivity of Sn melt increases. But there is an anomalous change in the vicinity 673K, it results in a discontinuous change in electrical resistivity of Sn melt.

The Al-7%Si /9% Al63Cu25Fe12 composites were fabricated by mechanical stirring method. The composite took Al-7%Si as matrix, Al63Cu25Fe12 icosahedral quasicrystal as reinforced particles. The microstructure and chemical composition of composites were investigated by means of SEM and energy dispersive spectrum (EDS) analysis and the mechanical properties was also measured. The results showed that Al63Cu25Fe12 particles were fractured and passivated after added into the Al-7%Si matrix, and distributed homogeneously along the crystal boundaries.The quasicrystal was not decomposed. Mechanical properties of the as-castand alloy were improved obviously.

A four-probe dc method for measuring the electrical resistivity of liquid quasicrystal Al63Cu25Fe12 was investigated in this article and found out that the resistivity of the melt temperature negative factors. Resistivity in alloy melting temperature near the lower interval occurred in phase I and λ, but is not happen to shift in β phase. That would not cause phase change of electronic transport, may be held without fracture, and held the bond length is changed. The viscosity of liquid quasicrystal Al63Cu25Fe12 was tested by using torsional oscillation viscosity measurement. Anomalous change at the temperature of (1401-1473)K occurred from the viscosity-temperature cures, some liquid-liquid change has taken place at this temperature.

SiC coatings were fabricated by the Rapid Chemical Liquid Deposition (RCLD) on the surface of graphite, the influence of deposition temperature on the microstructure of SiC coatings was investigated, the oxidation behaviors of SiC coatings at different temperatures were analyzed. The results indicated that the optimum condition for the SiC coatings are at 1150°C, a smooth and dense coating will be obtained, the thickness of the coatings are between 80～120μm. The oxidation resistance test results indicated that after oxidation at 1000°C for 5h, the mass loss of the sample is only 21%.

In this paper, TiAl intermetallic compound superfine powder is prepared through mechanical alloying and heat treatment, of which the content of TiAl intermetallic compound may reach 95%, and TiAl-based wear-resisting composite are obtained via hot-press sintering process and addition of solid lubricant, furthermore the preparation process, microstructure and friction and wear property of TiAl-based wear-resisting composite are studied. The experimental results show, the solid lubricant in the composite is stable and doesn’t react with components of TiAl-based materials. The friction coefficient of the composite will gradually decrease with the increase of the amount of solid lubricant CaF2+BaF2, and the minimum value 0.386 will appear when amount of addition is 15%, where the adhesive wear of materials decreases. When the amount of the addition is 15%, the wear rate is up to the lowest, but it’ll increase instead in case that the amount of addition is more than 15%.

A new method of carbon nanotube with electroless plating of nickel is proposed. It is shown that in a certain condition, the compacted and well-distributed coating of nickel is obtained without the process of sensitization and activation. Upon the surface treatment of the carbon nanotube, the CNT-consolidated composites for copper-based electrical contact have been made in the way of powder metallurgy. Some important mechanical properties and physical properties, including sliding wear property, electrical conductivity and fusion resistance, were investigated. The experiment results showed that Carbon nanotube inside the composite was uniformly distributed and a proper addition of CNT effectively improves the comprehensive property of the composites. When the carbon nanotube takes up 4vol. % in the material, it is highly effective in improving its sliding wear property and fusion resistance; though its electrical conductivity drops. Its overall properties meet the requirements of electrical contact materials

On the basis of measuring the viscosity of Sn melt and referring to analysis of high temperature XRD, the change of viscosity and structure for Sn melt with temperature were carried out. The results show that there is discontinuous change of viscosity for Sn melt with the temperature. The state of Sn melt are divided into high, middle and low-temperature region according to the change of viscosity, and there is an anomalous point of viscosity change between different temperature region. There is a correlation between the viscosity change of and the structure change of Sn melt. The coordination number and correlation radius, and the fluid cluster size of Sn melt decrease with the increase of temperature, so that the viscosity of Sn melt decrease. But there is an anomalous change in the vicinity 673 K and 1073 K, it results in discontinuous change in viscosity of Sn melt.

Copper-based electrical contact materials were prepared by Spark Plasma Sintering (SPS) method and powder metallurgy with the addition of different proportions of rare earth (RE) element. It is found that SPS method greatly enhances the density, hardness and conductivity of the composite materials, thus improving their comprehensive properties. Compared with powder metallurgy, SPS boasts a shorter sintering time, smaller compression force and higher efficiency. RE has considerable influence on the comprehensive properties of copper-based electrical contact materials. When the content of RE lower than 0.1%, the comprehensive properties can be improved by increasing RE.

In the present work, the resistivity of Ga36.5Sb63.5 alloy during cooling process was studied by the method of DC Four electrodes . The result of the experiment showed that there is an anomalous point at 710°C－735°C on the resistivity-temperature curve of Ga36.5Sb63.5 melt. At the same time, The relevance of the resistivity and the liquid structure of the alloy was analyzed. The physical properties of Ga36.5Sb63.5 alloy melt was discussed.

Rheological behaviors of Sn melt were systematically studied using a comprehensive measurement instrument designed in our lab. Structure of the Sn melt was analyzed by a liquid XRD technology. The result indicates that in the vicinity of 400°C, 800°C and 1200°C, the melt is a non-Newtonian fluid, while it is a Newtonian fluid within the temperature ranges of 400—800°C, 800—1200°C and over 1200°C. It is evidenced that the rheological property of the Sn melt is correlated to the changes in the melt structure. When the temperature is raised, the correlation radius rc, the coordination number Ns decreases, while in the vicinity of 400°C and 800°C, the correlation radius rc and the coordination number Ns of the Sn melt all show discontinuous changes.

The relationship between the viscosity of Al84Mg10Ce6 alloy melt and liquid structure was studied by viscosity measurements, X-ray diffraction and DSC analysis in this paper. In addition, the glass forming ability of alloy ties produced by melt spinning was analyzed. Based on the above results, the relationship between alloy melts and its glass forming ability(GFA)was studied. The addition of element Ce leads to the abnormal change of Al84Mg10Ce6 melt’ s structure and enhances its GFA, furthermore, it results in completely amorphous ties with melt spinning at 850°C.Therefore, there is certain relationship between the Al-Mg based alloys melt and its GFA.

The temperature dependence of resistivity of liquid Bi33.3Ga66.7 and Bi12Ga88 alloys was measured. Anomalous negative deviation of electrical resistivity of liquid alloys was found near critical temperature. Analysis in terms of the calculating equation for resistivity of liquid alloy suggests that, besides SCC(0), the pseudopotential matrix element and alloy composition still serve as crucial factors in scattering function. That is, concentration-concentration fluctuation in the long-wavelength is not necessarily induced an increase of resistivity of liquid alloy near critical temperature.

The SiC gradiently coated carbon fiber/carbon (Cf/C) composites were prepared by a two-step rapid chemical liquid deposition (RCLD) method. The microstructure and properties of the composites were investigated using X-ray diffraction, scanning electron microscopy together with energy dispersive X-ray analysis, bending tests, and oxidation tests. The experimental results show that the surface layer of the composites is composed of SiC, pyrocarbon, and carbon fibers. Their inner area consists of pyrocarbon and carbon fibers. The SiC content gradiently decreases with increasing distance from the outer surface to the center of the composites. Furthermore, the thickness of the SiC layer increases with increasing tetraethylorthosilicate content and deposition time. SiC coatings have no significant influence on the bending strength of the composites. However, the oxidation resistance of the composites increases with increasing thickness of the SiC layer.

This paper suggested that the addition of a proper amount of mischmetal efficiently improved the contact face and its mechanism of contact materials, enhancing their electrical conductivity. At the same time, their inoxidizability and non-fusibility were also highly improved, while the temperature elevation of the contactor during operation was dramatically reduced.

Si3N4/ Al–Mg composites reinforced by ceramic interpenetrating network structure had been fabricated via pressureless infiltration technology. The matrix and the reinforcement phase, form an interconnected interpenetrating network structure. The Al–Mg/Si3N4 system exhibits an excellent wettability under moderate conditions. The increasing of Mg content (2–10 wt%) resulted in an increased amount of infiltration, once Mg content beyond 10 wt% has an adverse effect. Light chemical reaction occurs in the interface of Al–Mg/Si3N4 system and the reaction productions reduce the surface tension of melt and impulse the advance of infiltration. Infiltration temperature and infiltration time were the key parameters, which turn into the infiltration impetus. The appropriate infiltration temperature is 1050 °C and the corresponding infiltration time is 15 min, prolonging the infiltration time continuously has no significance.

One kind of 3DNMMC with different volume fraction reinforcement phase was fabricated by pressureless technique. The bending strength and fracture toughness were tested by 3-P bending strength experiments. When the volume fraction of reinforcement phase phase was not in excess of 10%, composites had an improvement of bending strength and fracture toughness owing to relatively homogeneous Al2O3 particle distribution encircled by metal matrix and the occurrence of interface reaction product as MgAlO2 spinel phase. Much and smaller craters and dimples are observed in metal matrix alloy and limited ductility of composites causes the early failure of composites. With the increases of volume fraction of reinforcement phase phase, crack characteristic consist of crack nucleation, growth, coalescence and crack propagation became the main fracture failure mechanisms.

The viscosity-temperature curve of Bi melt showed that the viscosity values deceased with the increase of temperature. However, the discontinuous changing pattern took place on the viscosity curve. Viscosity of Bi melt can be divided into three parts as high temperature zone, moderate temperature zone and low temperature zone according to its change rate with temperature. The temperature ranges of the abnormal viscosity change were about 400~430°C and 610~640°C. With the DSC analysis, the abnormal phenomenon was explored from the microscopic structure viewpoint. It was assumed that the change from inhomogeneous atom configuration to homogeneous one led to the discontinuous variation, which is related to the bond transformation with the increase of temperature in melt Bi.

Adopting two-step deposition processes, SiC concentration gradient layer on the surface of Cf/C composites were prepared via Self-heating Chemical Liquid Deposition (SHRCLD) technique. In second deposition process, carbon and SiC were codepositted from pure kerosene and TEOS. The temperature of deposition was 1000°C~1200°C and the system pressure was 0.1MPa. Different thickness of gradient layers would be attained via adjusting the proportion of TEOS in procurer and controlling deposition time. Oxidation resistance, and mechanical tests were investigated, and the microstructure was observed under SEM. Results showed that the flexural strength of the composites was 123.7 MPa. The antioxidation temperature of Cf/C composites with the gradient layer is up to 800°C in air. The process of SHCLD technique is simple and easy to be controlled, and the deposition rate is faster than other conventional technique.

A multiphase reticulated porous ceramic (RPC) as Si3N4–Al2O3–SiO2 was fabricated by replication techniques. Proper volumes of additives and twice sinter- twice immerse process endow the RPC an excellent crack healing and submerging property. The compressive strength and fracture toughness improved owing to the crack bridging behavior. The existence of pores in struts in RPC blunt the crack tip and increased the external force needed to propagate the crack. The mechanisms play a beneficial role in enhancing the compressive strength and fracture strength. Si3N4 RPC with additives of 5%Al and 5% Al2O3 yielded the compressive strength of 9.8 MPa and fracture toughness of 0.3 MPa m1/2.

Reticulated polyurethane was chosen as the preceramic material for preparing the porous preform using the replication process. The immersing and sintering processes were each performed twice for fabricating a high-porosity and super-strong skeleton. The aluminum magnesium matrix composites reinforced with three-dimensional network structure were prepared using the infiltration technique by pressure assisting and vacuum driving. Light interfacial reactions have played a profitable role in most of the ceramic-metal systems. The metal matrix composites interpenetrated with the ceramic phase have a higher wear resistance than the metal matrix phase. The volume fraction of ceramic reinforcement has a significant effect on the abrasive wear, and the wear rate can be decreased with the increase of the volume fraction of reinforcement.

Metal matrix composites reinforced by three-dimensional (3-D) continuous network structure reinforcement (3DCNRMMC) are difficult to machine due to serious tool wear and poor surface roughness caused by the brittle and hard reinforcement which interpenetrate into ductile matrix. In order to achieve the approach of low cost of 3DCNRMMC, the machinability of it needs to be understood. The influences of three cutting parameters and volume fraction of reinforcement on cutting force were analyzed in detail. The results indicate that: (1) Due to the brittle phase(s) introduced into ductile matrix of composites, there is a large fluctuation of cutting force causing deterioration of machinability. The fluctuation ranges of cutting forces, initially increase rapidly with the increase of volume fraction of reinforcement and then decrease finally, are largest at the range of the volume fraction of 55–65%; (2) The influence of cutting parameters on cutting force is obvious. With the increases of cutting speed, cutting force decreases gradually unless cutting speed exceeds the value of 209 m/min. Cutting forces increase with increasing feed rate and depth of cut; (3) Owing to the large fluctuation of cutting force, there were some cratered surfaces caused by Si3N4 reinforcement pulling-out and flaking-off. Some brittle phase protruding from the machined surface caused the deterioration of machined surface.

One kind of three-dimensional network structure, reinforced aluminum magnesium matrix composites, has been prepared by pressure-assisted and vacuum-driven infiltration technology. The composites interpenetrated with ceramic have higher wear resistance than the metal matrix owing to their special topology structure. The reinforcement volume fraction has a large effect on abrasive wear. The wear rate decreases with the increase of the volume fraction of reinforcement and increases with the increase of sliding time and applied load. The wear mechanism of the composites (abrasive wear) differs greatly from the matrix alloy (adhesive wear).

Magnesium matrix composites reinforced by three dimensional (3-D) network structure were fabricated by pressure-less infiltration technology. The 3-D network structure reinforcement and its composites exhibited special topology structure and different fracture characteristic. Metal matrix fractured in a ductile mode is manifested by small dimples and craters on the fracture surface. When the volume fraction of reinforcement is not in excess of 6%, the composite had an improved fracture toughness. This is because of the relatively homogeneous Si3N4 particles distributed in the metal matrix and the occurrence of interface reaction product such as MgAlO2 spinel phase. With the increases of volume fraction of reinforcement (>6%), the fracture toughness decreases slowly at the initial stages and then decreases rapidly towards the end. Therefore, the main fracture failure mechanisms consist of crack nucleation, growth, coalescence and crack propagation.

Shear viscosities of Aluminum are determined with nonequilibrium molecular dynamics (MD) simulations using a Tight-Bonding potential. Viscosity of pure Aluminum melts is clculated using a 500 atom system at each temperature. And morever, viscosity is calculated with Andrade Equation The MD results for Aluminum are in good agreement with the experiment and Andrade Equation's calculated results.