Advanced Materials Research Vols. 299-300

Abstract: Based on the active variable stiffness, a new semi-active control method, whose principal content is using frequency control (FC), is presented. As a new semi-active algorithm, short time maximum entropy analysis is firstly proposed and the exact time and frequency signal at every control short time sequence also is given. The calculation results of a case of a 40-story building showed that the FC method is more effective than the results calculated by the method in the current structural design of tall buildings. The robustness of the algorithm is obtained and the displacement of the structure is reduced effectively.

Abstract: It will be no damage for small non-metallic inclusions by non-aqueous electrolytic technique. However, there are some unsolved problems: the interference of by-product, the corrosion of small inclusions and the low efficiency. PH value, colloid and electrolytic efficiency were discussed in this paper to optimizing electrolysis parameters. Finally, ultrafine non-metallic inclusions were extracted successfully with high efficiency. The results showed that complex oxides and sulfides were kept well and the contents of by-product were reduced distinctly. Three dimensional morphology inclusions were observed with clear background.

Abstract: The metallurgical behavior of adjusted converter slag components during the selective reduction process were investigated by thermodynamic calculating with different modified slag composition, addition of reducing agent and reduction temperature. The activities of main slag components were drawn from the calculated values. The results showed that the activity of SiO₂ increased with increment of its mass fraction in slag. The solubility of SiO₂ increased with increment of temperature. The selective reduction was promoted by selecting the appropriate amount of modifier. Reduction order was elucidated in this paper, Fe was reduced from the slag followed by P, Mn and Si and the reduction rate of Si could reach about 51%. The metal phase was rich in Fe, Si, Mn and P as a result of the selective reduction.

Abstract: Stainless steel web reinforced AZ91 alloy were fabricated by melt infiltration casting method. The mechanical properties of the resultant composites were much improved in regarding to the elastic modulus, 0.2% offset yield strength, ultimate compressive strength and the strains compared to the unreinforced counterpart. The interaction between the web and the dislocations in the matrix and the load transfer from the matrix to the reinforcement are the strengthening factors. While the wire being broken, bended and pulled out of the matrix, especially the activation of much more slip bands in the matrix, suggest that both the load transfer mechanism and the dislocations proliferation mechanism contribute to the plasticity of the composites.

Abstract: The correlation among boron, microstructure and mechanical property of the X120 pipeline steel was investigated in this study. The mechanical properties of the steels were tested with quasi-static tensile testing machine. The microstructure of the steels with different boron contents was observed with scanning electronic microscope (SEM) and transmission electronic microscope (TEM). The result shows that by adding a small amount of boron the mechanical property of pipeline steel can be improved effectively.

Abstract: Two kinds of X80 high deformability pipeline steels have been processed by applying two-stage cooling process (TSC) and heat treatment on-line process (HOP). The microstructure of TSC steel and HOP steel are polygonal ferrite (PF) + quasi-polygonal ferrite (QF) + granular bainite (GB) multiphase and QF + GB+ martensite-austenite (M/A) multiphase respectively. In HOP steel, the volume of M/A is much more and the size is much larger than that in TSC steel. Some degenerated M/A constituents are also observed in HOP steel. The HOP steel has shown higher tensile strength, lower yield ratio and lower uniform elongation than TSC steel. The strain-n_I (instantaneous n-value) curve of HOP steel could be divided into two stages and the TSC’s could be separated to three stages.

Abstract: Statistical values of valence electron structure parameter for phase structures of super saturation solid solutions in the initial aging stage of Al-Cu-Mn alloy were calculated by using the Empirical Electronic Theory in solid and molecules (EET), then the influence of various kinds of unit cells on the aging initial stage of the Al-Cu-Mn alloy subjected to the electron pulse modification was analyzed. The results show that the a-Al-Cu-Mn phase structure unit (cell) with larger atomic distortion provides the driving force for the saturated Al-Cu-Mn alloy to form G.P quickly and results in the increase in the primary nucleus of Al-Cu-Mn alloy; thus the a-Al-Cu-Mn phase structure unit (cell) playes an important role in the improvement of alloy aging. After the application of pulsed electric field into Al-Cu-Mn alloy melt, the movement of atoms is accelerated, and the number of segregation units of Al-Cu-Mn is increased, as a result the number of the second phase is increased; generating the remarkable aging strengthening.

Abstract: Compound silane films were prepared on galvanized steel by immersing method using mixture of bis-[3-(triethoxysilyl)propyl]tetrasulfide and γ-aminopropyltriethoxysilane. The corrosion resistance of galvanized steel substrates was compared after treatment with bis-[3-(triethoxysilyl)propyl]tetrasulfide, γ-aminopropyltriethoxysilane and their mixture in 3.5%NaCl solution by potentiodynamic polarization and electrochemical impedance spectroscopy. The results indicated that corrosion current density of the mixed silane films was reduced evidently and self-corrosion pressure of that was shifted to left markedly and total impedance value of that increased about two orders of magnitude. The analytical characterisation was performed by Fourier transform infrared spectroscopy and atomic force microscopy. The results showed that bis-[3-(triethoxysilyl)propyl]tetrasulfide and γ-aminopropyltriethoxysilane were all connected with the former of films.

Abstract: The effect of heating temperature and pulling rate on Young's modulus of steel FAS390Q was studied. The results show that the relationship between Young's modulus and reciprocal of absolute temperature follows exponent change, and Young's modulus and pulling rate follows power function relation (power index for 0.189). Crystal vacancy is one of the most important reasons for elasticity phenomenon of steels, which results in the fact that the Young's modulus is affected by pulling rate. Based on the statistical analysis, the mathematical model between Young's modulus of high temperature and pulling rate is established.

Abstract: In situ observation of growth process of high temperature phase in 0.15% C carbon steel during solidification concerned with using Confocal Scanning Laser Microscope (CSLM), the growth rate of -phase has been measured. The results indicate that high temperature -phase grows at cell crystal way when the cooling speed reaches 2°C/min in 0.15% C carbon steel. The -phase of round or oval cross-sectional shaped may grow stably. The growth rate of -phase is gradually getting slow along with increasing of curvature radius. The variation of growth speed tends to be similar with different solid-liquid interface shapes of -phase. The growth rate of concave solid-liquid interface is faster than that of convex solid-liquid interface for phase. The smaller radius of curvature of phase is, the faster the growth rate reaches.