Papers by Keyword: Topography

Abstract: The experimatal alloys were aged at different temperatures of 180°C, 200°C, 220°C, and 240º C with calcium addition levels of (X=0.5, 1, 1.5, 2%) on Mg-6Al-1Zn-XCa alloy were investigated in 3.5% NaCl solution. All the experimatal alloys were immersed in 3.5% NaCl solutions and the resulted surface were analyzed to study the corrosion behaviour and its surface topography by optical microscopy (OM), scanning electron microscopy (SEM), energy dispersed spectroscopy (EDS) and X-ray diffraction (XRD) techniques. The result shows that corrosion attack occurred predominantly on ß phase and α phase exhibit relatively minor corrosion. In addition to that the increased aging temperature coarsens the intermetallic as well as α- Mg grains, which shows adverse effect to corrosion resistances and the best result were obtained at composition of 0.5wt.% Ca aged at 200°C.

Abstract: Changes in fluids contact angle in the interaction with materials surface can play a critical role in enhancement of hydro-machine components and pipelines efficiency and/or service lifetime. However most nowadays used materials and/or coatings are made from polymers or ceramic polymer composites produced by highly sophisticated and/or very expensive techniques. Unfortunately there are a lack of mechanical properties. With the aim to study the role of the surface topography on the water contact angle changes, the representatives of wear resistant coatings (WC10Co4Cr, Cr₂O₃+5SiO₂+3TiO₂ and Al₂O₃) were produced by means of atmospheric plasma spraying. Wettability of the coatings surface was studied by adding the liquid droplet on as sprayed, grinded and polished coating's surface by measuring the changes of its contact angle. To estimate the coatings phase composition and topography XRD technique and optical profilometer were used. The contact angle of water was measured by sessile droplet method. To obtain the complex information of the cross-sectional coatings microstructure the conventional metallographic analysis approaches and optical microscopy were also used.

Abstract: In precision milling, the quality of surface finish is an important requirement for workpiece machined. Thus, optimization of cutting parameters is important for controlling the surface quality. In this study, the Taguchi method is used to find the effects of milling parameters on surface roughness in precision milling of 3J33 maraging steel. A model, which is based on the milling parameters and tool geometry, is also proposed in order to predict the surface topography. The experimental results show that milling speed has significant effect on the surface roughness among the milling parameters. Besides, tool geometry and material deformation play important roles in the surface topography.

Abstract: Definitive correlations are presented between specific types of dislocations identified via Synchrotron White Beam X-Ray Topography (SWBXRT) and identified via selective etching of 4H-SiC substrates. A variety of etch conditions and the results on different faces of SiC substrates and epiwafers are examined. Hillocks formed on the carbon face of the substrate after KOH etching correlate very well to TSDs identified via SWBXRT. Topography of substrates and of vertical crystal slices reveals a large proportion of Threading Mixed character Dislocations (TMDs) in the population of Threading Screw Dislocations.

Abstract: This paper describes 3D imaging of extended defects in 4H-SiC using optical second-harmonic generation (SHG) and two-photon-exited photoluminescence (2PPL). SHG selectively yields the 3D images of 3C-inclusions in a 4H-SiC epilayer, while 2PPL provides 3D images of 3C-inclusions, 8H stacking faults and single Shockley stacking faults. 2PPL band-edge emission visualizes dislocation lines of threading screw dislocations and threading edge dislocations, the tilt angles of which are evaluated.

Abstract: Honing experiments were carried out for nickel-based superalloy Inconel718 bore. The significance analysis of the four honing parameters: spindle speed, stroke speed, wedge feed per stroke cycle and grain size on the surface roughness, was studied with the orthogonal design method. And the significant degree under the rated conditions was determined. The results showed that: wedge feed per stroke cycle and grain size have a significant influence on surface roughness while spindle speed and stroke speed had no significant effect. Also, there was a positive correlation between surface roughness and wedge feed per stroke cycle and grain size. Furthermore, the honed surface topography was analyzed by the meaning of microscope.

Abstract: In this paper the way to numerical modeling of surface details after finishing is examined. Feature of the presented model is a sequence in the simulation results: at the beginning surface is modeled after processing by grinding and only then topography is modeled after burnishing. Simulation of a burnishing tool on close to real surface but not on the perfect surface allows considering the effect of technological heredity, which is important for the engineering manufacture.

Abstract: Results of development of geometrical model of a shaping of a polished surface at surface grinding by the periphery of a wheel are presented in article. The developed model allows to predict a roughness of the processed surface depending on basic parameters of operation: speeds of rotation of the tool and translational motion of workpiece, wheel parameters – granularity and structure, depth of cutting and other parameters. Results of experimental check of the developed model are given in article.

Abstract: Topographic mapping and modeling is one of the most basic and important work in hydraulic engineering construction. This paper present a work flow which contains data measurement, pre-process and post-process with three dimensional laser scan technology. By adopting B-tree and its expansion structure, a multi-level point cloud management and storage method has been established. Then propose a contour generation method based on scan data and the equivalent point interpolation data. A self-adaptive mesh Delaunay algorithm is introduced with point cloud data in order to generate triangular irregular network digital elevation model. Finally, the modeling accuracy and error has been analysis, the results proves this method is with high efficient and accuracy and can be provide assistance for the project construction.

Abstract: The measurements were performed on the surfaces made of different materials and typical of diversified character. Glass roughness standards with sinusoidal profile, approximately sinusoidal profile and metallic comparative standards after lathing and grinding were object of research. Analysis was performed including the surface and profile evaluation. Statistical analysis was conducted. Measurement sections and other filter parameters were selected in accordance with standards. Measurements were carried out with stylus tip contact method – using TOPO 01P device designed by The Institute of Advanced Manufacturing Technology, that uses diamond tip inductive sensor. Tip sensor radius is equal to 2 μm. The results of measurements were filtered by: Gaussian filter, Robust Gaussian regression Filter, Spline, Spline Wavelet, Morphological Filter. Gaussian Filter uses linear system based on Fourier wavelengths. Robust Gauss Regression Filter is similar to Gaussian Filter, but it is insensitive on the specified phenomena in input signal. Spline Filter is based on linear polynomial combination. Wavelet Filter decomposes profile on constant shape elements, but on different scales. Morphological Filter operates on the principle of filtered profile plotting using circular disc or horizontal line segment with a specified (respectively) radius or length. Selection of suitable filtration method is essential and one of the most important things to obtain reliable measurement results evaluation. Not all filters are suitable for each type of surface. Filter algorithms differ from each other and this influences in a greater or lesser degree on the roughness profile and hence on roughness parameters and waviness parameters related to it.