Advanced Materials Research Vol. 740

Abstract: The catalysts La_0.8K_0.2FeO₃ (LKFO), La_0.8K_0.2Fe_0.7Mn_0.3O₃ (LKFMO) and La_0.8K_0.2Fe_0.67Mn_0.3Pt_0.03O₃ (LKFMPO) were prepared by the citrate-gel process and the catalyst-coated honeycomb ceramic devices were prepared by the citrate-gel assisted dip-coating method. All the catalysts have a high performance on the simultaneous removal of NO_x and soot at a temperature range of 200 to 400°C under the practical diesel exhaust emission. The obvious catalytic improvement is largely due to the effects of ions substitution, pore structure and microstructural characteristics of the catalysts. The catalytic performance order is LKFMPO > LKFMO > LKFO. Among them the LKFMPO catalyst shows the best catalytic properties, especially in the removal of NO_x, with a maximum conversion rate of NO_x (21.2%).

Abstract: The governing equation of thermoelastic FGM thin plates was obtained by degenerating the governing equation of thermoviscoelastic FGM thin plates. A Navier solution of a simply supported FGM rectangular plate under thermal loads was get. Based on the Navier solution, the influence of considering and ignoring mid-plane stain, due to the inhomogeneous property of the functionally graded materials, on the maximal deflection and thermal stress of the functionally graded materials thin plate is investigated.

Abstract: The governing equation of elastic FGM thin plates was obtained by degenerating the governing equation of viscoelastic FGM thin plates. A Levy solution of a simply supported FGM rectangular plate was gotten. Based on the Levy solution, the influence of considering and ignoring mid-plane stain, due to the inhomogeneous property of the functionally graded materials, on the static responses of the functionally graded materials thin plate is investigated.

Abstract: There is no literature mentioning the dynamics of a micro beam on which a harmonic force traveling to and fro. This article is the first to present the dynamics of a micro beam subjected to a traveling harmonic force, especially the effects of the frequencies and traveling speed on the dynamics of a micro beam. According to analytical results and the simulation results by ANSYS, the resonant frequencies of a micro-beam will be bifurcated by the traveling harmonic force. One frequency of the external force may simultaneously excite two vibration modes at some particular traveling speeds. The micro structure may become unstable at particular traveling speed.

Abstract: Dual-phase steels of 09CuPCrNi are prepared through intercritical quenching process. The influences of dual-phase treatment on the corrosion resistant property of the steels have been studied by electrochemical potentiodynamic tests and artificial salt spray tests. The results indicate that the corrosion behavior of DP780 and the as-received weathering steel in 5% sodium hydroxide, 3.5% sodium chloride, 5% sulphuric acid and various concentrations of hydrochloric acid solutions are identical, but dual-phase steels show least corrosion current as compared to the as-received steel. Rust layers of the as-received steel and DP780 are identical mainly consisting of three iron (hydr) oxides, goethite, akaganeite and lepidocrocite, and magnetite. Both the relative amount and morphology of phase constituents affect on the corrosion behavior of DP steels.

Abstract: The extraction of grains geometrical features in steel microscopic image is the important basis of metallographical analysis. In order to analyze the geometrical features automatically, firstly, we applied the double-threshold binarization and morphological transform to segment the grains and their boundaries from the gray images. Then, we presented a grain boundary tracking algorithm to separate each grain from others. Finally, we gave the definitions of grains various geometrical features (such as its size, average area, average diameter, uniformity degree and lubricity degree etc.) and their estimation methods. The experimental result shows that the given image processing method can extract grains and their boundaries efficiently. The proposed measurement methods of grains geometrical features in steel microscopic image are very helpful for more deep analysis such as the grain level evaluation, mechanical property analyzing and so on.

Abstract: In this paper are presented information about common and advanced materials used for manufacturing of products by Fused Deposition Modelling (FDM) rapid prototyping technology. In different rapid prototyping technologies the initial state of material can come in either solid, liquid or powder state. The current range materials include paper, nylon, wax, resins, metals and ceramics. In FDM are mainly used as basic materials ABS - Acrylonitrile Butadiene Styrene, polyamide, polycarbonate, polyethylene and polypropylene. Main part of the paper is focused on experimental testing of rapid prototyping materials realized by different research teams and presents outputs of testing of ABS material in FDM technology realized by authors.

Abstract: Inner corrosion defects have great effects on the life and safety of the oil and pipelines. To predict the safety by the surface strain and stress condition, ANSYS software was applied to analyze the effects of the inner corrosion defects size (diameter and depth) on the surface strain and stress value. The combined effects of defect diameter and depth on the circumferential direction strain of pipeline were obtained. The simulation results indicate that there is a linear relationship between circumferential direction strain and the defect diameter, an exponential relationship between circumferential strain and defect depth. Furthermore, there is a proportional relationship between the circumferential strain and the operating pressure of the pipeline. An empirical formula to calculate the surface strain used the defect diameter, depth and the operating pressure was developed based on the numerical simulation data. The experimental results verify the reliability and validity of this empirical formula for engineering prediction application.

Abstract: The influence of Cr on corrosion behavior of P110 steel was studied in the simulated CO₂ environment. The result demonstrated that the Cr cant change the effect of temperature on P110 steel. The corrosion rates of the two kinds of materials reached the peak at 90°C. The temperature has dual effects on corrosion, which caused the adhesive and productivity of corrosion product formed up 90°C are better than that formed below 90°C; The adding of Cr in the P110 steel can prohibit the local corrosion to occur.

Abstract: Grid method was used to measure the stress intensity factor K_I of a mode I fracture specimen. The fracture specimen used in this study was a compact tension (CT) specimen made of 6061-T6 aluminum. A grid of dots was bonded along a radial line on the surface of the CT specimen. A 2D computer vision was used to acquire the images around the crack tip before and after the deformation of the CT specimen. Then the method of single dot was used to measure the magnitude and direction of the in-plane principle strains at the dot centers. Experimental results indicate that the measured strains can be used to accurately determine K_I.