Abstract: Interface performance investigations of turbine rotor alloy (30Cr2MoV) in 0.01M Na2MoO4 have been performed by means of Electrochemical Impedance Spectroscopy (EIS) under step potential change conditions. A general equivalent circuit was employed to analysis the polarization behavior of that turbine rotor. It has been shown that EIS measurements under potentiodynamic conditions allow simultaneous investigation of changes in interface structure, ions transport process through the interface and electrode process kinetics on interface. The result verified the adsorption principle on metal passivation.
Abstract: In this paper, the interface characterization and materials flow pattern of overlap joints of dissimilar alloys of 6061-T6 aluminum alloy and AZ31B magnesium alloy welded by friction stir overlap welding with a reverse conical pin tool were investigated. The results shown that: when AZ31B magnesium alloy sheet was placed over 6061-T6 aluminum alloy sheet, and AZ31B magnesium alloy sheet was settled at advancing side while 6061-T6 aluminum alloy sheet was at retreating side, it could eliminate the influence of migration interface on the strength of the lap joints. What is more, the intermetallic compound Mg17Al12 were formed at advancing side of magnesium alloy sheet and retreating side of initial interface between magnesium alloy sheet and aluminum alloy sheet. According to the distribution of intermetallic compound and the characteristics of migration interface, the plastic flowing pattern of metal in welding process was also evaluated.
Abstract: Ferromagnetic glass ceramics with magnetism and biological activity could be used for magnetic induction hyperthermia. In this study Fe2O3-CaO-SiO2 glass-ceramics were prepared by sol-gel method. The sample was characterized by X-ray diffraction (XRD) and differential thermal analysis (DTA). The results showed that the major phases of the sample are wollastonite and magnetite and the crystallization activation energy of sample is 189.3KJ/mol, which would provide a theoretical basis for the establishment of the optimum process conditions of heat treatment technology.
Abstract: This work aims to explore the sources of raw materials of archaic serpentine jade artifacts by comparing their trace element content. The major and trace elements of serpentine jade samples from different deposits in China are determined by external-beam proton-induced X-ray emission (PIXE). Trace element concentrations are also measured by inductively coupled plasma atomic emission spectroscopy for comparison. The relationship between the trace element content and the mechanism of serpentine formation is discussed. The results indicate that Type I jade has a small amount of Ni in it and almost no Cr and Co while significant amount of Cr, Co and Ni was found in Type II jade. Thus, this could be used to distinguish the two kinds of serpentine jade formed by different mechanisms.
Abstract: The machining of superalloys has put really a challenge for technologists and researchers. The conventional techniques of machining do not give satisfactory performance for machining of superalloys. In this paper, the results of an experimental study for cutting of Inconel 718 superalloy with wire electrical discharge machining (WEDM) have been presented. Three different wire materials along with important input process parameters namely peak current, servo voltage, pulse on time and pulse off time have been selected. The effect of these parameters on material removal rate has been investigated by using well know experimental technique called response surface methodology. The experimental results indicate that zinc-coated brass wire is most suitable for Inconel 718. An empirical model has been developed for correlating input parameters and material removal rate for zinc-coated brass wire. Analysis of variance has also been presented.
Abstract: Effects of annealing treatment on growth of rutile TiO2 nanorods on structural, morphological and optical properties of TiO2 nanorods were investigated. The nanorods were fabricated on p-type (111)-oriented silicon substrates and, all substrates were seeded with a TiO2 seed layer synthesized by radio-frequency reactive magnetron sputtering system. Chemical bath deposition (CBD) was carried out to grow rutile TiO2 nanorods on Si substrate at different annealing temperatures (350, 550, 750, and 950 °C). Raman spectroscopy, X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) analyses showed the tetragonal rutile structure of the synthesized TiO2 nanorods. Optical properties were examined by photoluminescence spectroscopy. The spectra exhibit one strong UV emission peak which can be seen at around 390 nm for all of the samples. In the visible region, TiO2 demonstrated two dominant PL emissions centered at around 519 and 705 nm. The experimental results showed that the TiO2 nanorods annealed at 550 °C exhibited the optimal structural properties. Moreover, the CBD method enabled the formation of photosensitive, high-quality rutile TiO2 nanorods with few defects for future optoelectronic nanodevice applications.
Abstract: Procedures of thermal diffusion (TD) process are carried out on two specimens of Cr12MoV steel using the same salt bath formula. For the two specimens, the beginning V concentration, V concentration at the time specimen is added, are different, the level of which is controled by changing the interval between the specimen are added and the time reducing agent of Al meeting with vanadizing source of V2O5. The interval for Specimen 1 and Specimen 2 are 10 and 30 minutes respectively. Consequently, different changes are happened on the surface of the substrates. The microstructures of coatings are observed by optical metallographic microscope and SEM/EDS, the hardness are tested by Vickers micro-hardness tester. Results show that: VC coating formed on Specimen 2 is of better performances than Specimen 1, microhardness of Specimen 2 reaches as much as 2400HV. It can be concluded that level of V concentration at the beginning of TD process is a vital factor for the forming of VC layer.
Abstract: The content discussed in this paper about 7150 aluminum alloy is based on the thermal simulation technology, which is an experiment using the way of temperature compression to do high temperature shaping and passes softening. And using the popular business-oriented finite element software simulates the related data of the multipass hot-rolling on 7150 aluminum alloy. By the obtained parameters, it carries out the hot-rolling experiment and processing of RRA technology. Based on this, it analyzes the experimental and data simulation of multipass hot-rolling on 7150 aluminum alloy.
Abstract: This paper makes test of degree of polymerization and molecular weight of common and inflaming retarding viscose in clothing material. And then it analyzes the effect of degree of polymerization and molecular weight on material fiber thermology and mechanical property. The research shows that the addition of fire retardant reduces degree of polymerization and molecular weight of material fiber, enhances flame retardant performance, and reduces mechanical property. Through the test research, we deeply compare the performance of inflaming retarding and common viscose on clothing material, which offers related reference value for the development of inflaming retarding function garment materials.
Abstract: Using ammonium chloride (NH4Cl) as model compounds of ammonia nitrogen metabolites of crassostrea rivularis (oyster), the corrosion process of steel alloys by ammonia nitrogen metabolites of oyster was carried out in simulated seawater. Using A3 steel for marine engineering steel as the sample, the experiments based on the corrosion coupon in natural sea, static coupon, scanning electron microscope and polarization curve were carried out. According to the corrosion morphology development of samples, the corrosion mechanism of attached corrosion of was revealed.