Applied Mechanics and Materials Vols. 556-562

Abstract: Since the first synthesis of an amorphous phase in Au-Si system from liquid, a great number of amorphous alloys have been prepared by rapid solidification. Almost all amorphous alloys require high cooling rates and a lot of studies have been carried out for these metallic glasses. In this study, metallic glass of Nd60Al10Cu20Ni10 have been fabricated, and experimental research was carried out to reflect thermal features. It indicates that the Nd-based amorphous has shown a distinct glass transition and stable super-cooled liquid region. The research results show that the paramagnetic performance of Nd60Al10Cu20Ni10 metallic glass is different from other hard magnetic alloys at ordinary temperature. From the DSC experiment, it is found that the glass transition temperature is increasing with the heating temperature.

Abstract: Powder metallurgy (P/M) superalloy has not only been the primary material of turbine disk but also the main material of packing disk, packing ring and baffle plate of the aero-engine. Among these components, some parts are very thin, for example, the thinnest of baffle plate is only 2mm. The thin plate component was subjected to complex load, and the failure mode was synthetical. Some parts of component are subjected to impact load or impact-fatigue load although the nominal load of this component is fatigue load, more than one baffle plates have cracked through fast expansion and burst multiple debris because of the different local load type for the same component. It is very useful to investigate the effect on tensile and impact properties by specimen shape and shot peening. In this article, the different tests were carried out, including different specimen shape, temperature and surfaces. The results indicated that fracture strength σ_b and elongation δ₅ were not affected by shape of specimen of P/M superalloy. Rod or plate specimens may be used to characterize the static properties of material. Shot peening would decrease the elongation,δ₅ (at room temperature and 650°C) and impact work, but it did not reduce the fracture strength σ_b. In order to utilize adequately the component subjected to complicated loads, the surface state of the component may be treated distinctively according to the specific local load.

Abstract: In order to predict the influences of electrical discharge machining (EDM) and enhance material removal rate (MRR). A model was presented for predictions of MRR in EDM TC11 test piece based on the construction method of gray GM(1,N) model and BP neural network model (GNNM).The results show that the GNNM is credible with the maximum absolute error 3.58%, the minimum absolute error 0.01% and the mean error 0.53%were obtained .The results indicated that the model can reflect the technological law of EDM TC11 and successfully predict its processing speed .The paper provides references and basis for selecting processing parameters of EDM TC11 and has practical significance.

Abstract: This report studied the influence of effects such as type, modulus, dosage of the alkali-activator on mechanical properties of slag-based geopolymer. The analyzing results indicate that compare to the Na₂SiO₃, K₂SiO₃ has significant activate effects on slag-based geopolymer. The modulus and dosage have obvious significance on early compression strength of slag-based geopolymer. With the increase of modulus, its early compression strength has apparent increase. With the increase of dosage, its early compression strength increase firstly and then decrease. When the dosage is 12%, the compression strength of the material is highest. The change of modulus and dosage of the alkali-activator has little influence on flexural strength of slag-based geopolymer. With the increase of dosage, its ratio of flexural to compressive strength has a downward trend. And the material brittleness addition.

Abstract: The CCT curve of a C-Si-Mn steel was investigated. The hot simulation tests at different cooling rates were conducted on Gleeble-1500 simulator and microstructures were observed. Based on transformation temperatures recorded by dilation curves and microstructures, the CCT curve diagram for tested steel was plotted. The effects of cooling rate on microstructure and transformation temperature were studied. The results provide the theoretical basis for determination of hot processing and heat treatment technology of C-Si-Mn steels.

Abstract: A donor-acceptor organic molecule based on fluorene unit as an electron donor and aldehyde group as an electron acceptor has been demonstrated in high yields over four steps. This approach offers a much milder and more efficient route to synthesize the target compound via the Vilsmeier-Haack reaction. Optical spectra show that the electron-accepting groups induce an intermolecular charge transfer, resulting in a shift of the absorbance maximum toward longer wavelength. Such D-A type intermediate compounds as organic molecules display a significantly improved property profile in photoelectrical materials for applications in organic light-emitting diodes (OLEDs), organic photovoltaics (OPVs), and organic field-effect transistors (OFETs).

Abstract: Based on the first-principles scheme, we have built several hcp-Al crystals and have calculated the lattice constants, cell volumes and elastic constants at high pressures using the plane-wave pseudo-potential method within ultrasoft pseudo-potentials. The basic thermal properties of Al are investigated by using the quasi-harmonic Debye model. The results show that the bulk moduli are still very large at high temperatures; hence hcp-Al can retain its stability at high pressure and high temperature. On the other hand, the temperature effects on the heat capacity and thermal expansion are significant. Several interesting phenomena have been observed in these quantities at T> 300K. More importantly, the negative shear moduli of hcp-Al indicate that our calculation results need to be verified by experiments in the near future.

Abstract: In order to study the mechanism of salt-bearing polymer flooding, using micro-flow technology, experimental study of salt-bearing polymer flooding residual oil process was carried outin two microscopic models of hydrophilic and lipophilic formation.Its microscopic percolation mechanism wasinspected. In hydrophilic model, after injecting salt-bearing polymer residual oil is capturedand migrated, and there is residual oil drawinganddeformation phenomena which is consistent with common polymer; while flooding process due to larger viscoelasticity of salt-bearing polymer, normal stress is generated in the flow, so the cutting action of the residual oil is obvious. In lipophilic model, after injecting salt-bearing polymer, residual oil migration, the film gathering,interface transport, a bridge and drawing phenomenon happened which is consistent with common polymer; polymer difference between salt-bearing polymer andcommon polymeris that from the ordinary and the residual oil film formed by common polymer is flexible and easier to form "emulsion.

Abstract: A new spectrofluorimetric method was developed for determination of trace amount of bilirubin. Using enoxacine–terbium ion as a fluorescent probe, in the buffer solution of pH=5.8, BR can remarkably reduce the fluorescence intensity of the ENX-Tb³⁺ complex at λ=545nm and the reduced fluorescence intensity of Tb³⁺ ion is in proportion to the concentration of BR. Optimum conditions for the determination of BR were also investigated. The linear range and detection limit for the determination of BR are 1.0×10^-7～4.5×10^-6mol/L and 8.1×10^-8mol/L. This method is simple, practical and can be successfully applied to assess BR in serum samples.

Abstract: Mo-Ni coatings were prepared on Ni alloy by electrodeposition method. The effects of sodium fluoride mass concentration, sodium chloride mass concentration, sodium molybdate mass concentration and pH value on deposition rate of Mo-Ni coating were researched, respectively. The morphology of Mo-Ni coatings were characterized with scanning electron microcopy (SEM). When sodium fluoride mass concentration is 12 g/L, deposition rate of Mo-Ni coating is as high as 0.3781 mg/cm²·min. When sodium chloride mass concentration is 22.3 g/L, deposition rate of Mo-Ni coating is as high as 0.2108 mg/cm²·min. When sodium chloride mass concentration, sodium molybdate mass concentration and pH value are 22.3 g/ L, 12 g/L and pH 5 respectively, deposition rate of Mo-Ni coating is as high as 0.2123 mg/cm²·min. There are many cracks and pits on the surface Mo-Ni coating deposited in the bath without adding NaCl or NaF, and coating surface is very uneven. The surface Mo-Ni coating deposited in the bath adding NaCl is smooth, and the grains of Mo-Ni coating is small. The surface Mo-Ni coating deposited in the bath adding NaF is smooth, and there are many nodules on the surface Mo-Ni coating.