Advanced Materials Research Vols. 311-313

Abstract: In order to find the reasons of that the hardness of 1Cr17Ni2 stainless steel partial components after being quenched is weakened, based on the sampling analysis on the partial components to produces the components to carry on the sampling analysis, and to compare the contrast that the maximum of the hardness of quenched material is lower than (the average value of the hardness – the standard deviation) to that the minimum is higher than (the average value of the hardness + the standard deviation), we draw an exciting conclusion. The Cr content in steel is on the high side and the Ni content is on the low side. Especially the components present low hardness after being quenched whose C content is low, and the components present high hardness after being quenched whose C content is high. The reason why components have low hardness is that the contents of the element C and Ni to making Austenite in the 1Cr17Ni2 stainless steel is low, the contents of the element Cr to making Ferrite is high, and the martensite hardness is low and the Ferritecontents is high after being quenched.

Abstract: A vacuum preloaded circular aerostatic bearing was designed and its static characteristics were investigated experimentally. The load carrying capacity and air film thickness of the bearing were measured for different air supply pressure and vacuum pressure values. An orthogonal table was constructed to optimize the experimental measurement. Regression analysis was performed on the experimental results to obtain an analytical model of the bearing stiffness as a function of the load carrying capacity, air supply pressure and vacuum pressure. Accuracy of this analytical model in predicting static characteristics of the aerostatic bearing was validated by comparison with experimental data, and influences of the functioning parameters were also discussed.

Abstract: Al-Ti-B-Sr-RE master alloys were prepared firstly by the reaction of complex halide salts with molten aluminum at 800°C, and then the addition of Al-RE and Al-Sr master alloys into the melt. The constituent phase and microstructure were characterized by XRD, optical microscope (OM) and scanning electron microscope (SEM). The element content was analyzed by spectrometer, X-ray fluorescence spectrometry and electron probe microscope. Ti₂Al₂₀RE, SrB₆, LaB₆, Al₄Sr and Al₁₁La₃ are the constituent phases in these master alloys. The constituent phases containing Sr and RE in the Al-Ti-B master alloy depend on the ratio of Ti and B. The critical ratio of Ti and B is 2.2:1. Obviously, SrB₆ and LaB₆ phases are the reaction products of AlB₂ with Sr or La during master alloy fabrication. The two layer lump-like Ti-Al-RE particles formation mechanism is proposed.

Abstract: In borate buffer solution, anodic oxide passive film was formed on 316SS at 0.6 VSCE. Chemical composition and semiconductor properties of the film were studied by XPS and capacitance measurement. It’s determined from the results that the film has duplex structure with inner oxide layer and outer hydroxide layer. The inner layer behaves as p-type semiconductor, while the outer layer shows n-type semiconductor. A p-n junction is formed at the interface of outer and inner layer, and it plays an important role in the protective effect on the metal matrix.

Abstract: There is no literature mentioned the modeling of the microstructures subjected to traveling electrostatic forces. This paper is the first time to present an analytical approach to investigate the dynamics of a micro-ring structure driven by the traveling bias voltage. The traveling electrostatic forces may come from the sequentially-actuated actuating electrodes arranged around the flexible ring. A linearized distributed model considering the electromechanical coupling effect is derived based on the small deflection assumption. According to the analytical results, the stiffness of the micro-ring will be softened periodically with the traveling speed of the driving voltage and the variation increases with the increasing of the voltage.

Abstract: An investigation has been carried out to determine the formation conditions of Ce₂O₂S and CeAlO₃ in cerium treated Al-killed steel. Argon protection melts have been manufactured of appropriate base steel compositions with varying additions of cerium (0.006-0.04%). The work has shown that 0.0015-0.02% may be retained in steels after Al deoxidation and cerium treatment while oxygen and sulphur content be 14-17 ppm and 60-70 ppm respectively. With 0.0099-0.02% retained cerium, resulting inclusions are largely spheroidal in shape and consist of several crystalline compounds, notably Ce₂O₂S and CeAlO₃. Thermodynamic analysis indicates that the CeAlO₃ would be formed with the cerium content in the range of 8.65ppb to 1.45ppm when the content of aluminum was 0.01%.

Abstract: The outer casing of heater made of iron-boron alloy is brittle fractured easily. It is a an effective way to add continuous fibers in brittleness material to improve the mechanical properties of composites. Temperature and thermal stress distribution of iron-boron alloy casing and the influence of thickness on the thermal stress of the casing is computed with finite element method, and the thermal stress distribution and influence of fiber volume fraction of continuous fiber-reinforced composites is studied. The result indicates that the external surface is in tensile stressed condition, and the internal surface is in compression stressed condition; the thermal stress increases with the thickness. The compression stress of the matrix decreases and the tensile stress increases with the increasing of the fiber volume fraction.

Abstract: Polyacrylate microgel emulsion was prepared by emulsion polymerization using styrene, α-n-butyl acrylate and methyl methacrylate as monomer, polyoxyethylene octylphenol ether (TX-30) and sodium dodecyl sulfate(SDS) as combine emulsifier, divinyl benzene and ammonium persulfate (APS) as initiator，respectively. The prepared microgel was analyzed by a variety of measurment methods, such as Fourier transform infrared spectroscopy and transmission electron microscopy. The effect of microgel on the rheological properties of adhesives, leveling, mechanical properties and pigment printing performance was studied. The rhelogy and the color fastness of the pigment printing binder of printed fabrics were measured by rheometer and friction color fastness test instruments, respectively. At the same time, the mechanical properties of the adhesive film was measured by strength tester. The results show that the thixotropy, leveling and mechanical properties of adhesive printing binder and pringting quality of coating fabrics were improved when the microgel was added.

Abstract: The method of analyzing capability and verifying correctness for workflow process is divided in static check and dynamic simulation. The focus of the paper is to test and analyze workflow process by means of dynamic simulation, further to confirm that a process will do appropriate things at appropriate time by appropriate resources. The paper will research some key issues in process simulation——setting up simulation environment, the algorithm for arranging events in a queue based on path coverage rule, analyzing simulation results. It adopts interactive and non-interactive means and makes use of white-box and black-box methods to test workflow process on the base of high coverage rate. At last the classification, distribution and trend of process defects will be presented by various simulation results.

Abstract: High performance rigid cross-linked PVC foam has been prepared by molding process and boiling foam process with the main materials including polyvinyl chloride paste resin (PVC), liquefied methylene bis-phenyl diisocyanate (MDI-L) and methylhexahydrophthalic anhydride (MHHPA). The chemical structure, cellular structure and thermal properties were respectively characterized by fourier transform infrared spectrometer (FTIR), scanning electron microscopy (SEM), thermomechanical analyzer (TMA) and thermogravimetric analyzer (TGA). Results showed that the foam had a uniform cellular structure, and cell size was about 760μm. The glass transition temperature (Tg) was 81°C and 5% weight loss temperature (T_5d) was 252°C.