Metallographic Preparation of Zn-21Al-2Cu Alloy for Analysis by Electron Backscatter Diffraction (EBSD)
Abstract Samples of Zn-21Al-2Cu alloy (Zinalco) that will be heavily deformed were prepared using five different manual mechanical metallographic methods. Samples were analyzed before tensile testing using the orientation imaging microscopy-electron backscatter diffraction (OIM-EBSD) technique. The effect of type and particle size during the final polishing stages for this material were studied in order to identify a method that produces a flat, damage free surface with a roughness of about 50 nm and clean from oxide layers, thereby producing diffraction patterns with high image quality (IQ) and adequate confidence indexes (CI). Our results show that final polishing with alumina and silica, as was previously suggested by other research groups for alloys that are difficult to prepare or alloys with low melting point, are not suitable for manual metallographic preparation of this alloy. Indexes of IQ and CI can be used to evaluate methods of metallographic preparation of samples studied using the OIM-EBSD technique.
Electron backscattered diffraction characterization technique for analysis of a Ti2AlNb intermetallic alloy
This investigation was conducted to ascertain the benefits of electropolishing after mechanical polishing for electron backscattered diffraction of a Ti2AlNb intermetallic Ti−21Al−29Nb (at.%) alloy containing the orthorhombic (O) and body‐centered‐cubic (BCC) phases. Electropolishing was performed at −40 °C in 6% H2SO4 methanol solution. Atomic force microscopy was used to measure the surface topography in attempt to correlate nano‐scale surface roughness with electron backscatter diffraction pattern quality. The results suggest that mechanically polishing with colloidal silica (SiO2) or alumina followed by electropolishing is a sufficient surface preparatory technique for producing quality electron backscattered diffraction patterns for O + BCC microstructures. However, poor pattern quality results after mechanically polishing without electropolishing. High‐quality orientation maps for O‐dominated O + BCC microstructures were only possible through mechanical polishing followed by electropolishing. The data also suggest that surface roughness, on the order of 50 nm, has less effect on pattern quality than subsurface deformation. Overall, removing the near‐surface damage was more critical than reduction of topography.
Research on Control and Planning of Soft-Wing UAV for Haze Removal
The existence of fog and haze has caused great pollution to the environment. The research of removing haze is a hot topic in recent years. In this paper, a special haze removal algorithm based on Soft- Wing UAVis proposed. In this algorithm, two track control strategies are designed based on the Soft-Wing UAV model transfer function. A SIMULINK platform based mathematical model of Soft-Wing UAV is built to testified effectiveness of the two track control strategies. An autonomous ergodic-planning algorithm with greedy strategy and foldback algorithm for Soft-Wing UAV is designed. Within the algorithm, the haze regional has been modelled, the cost matrix is constructed, and the planning and ergodic strategy is proposed. Finally, the experimental results validates the reliability of the algorithm in the application of haze removal with the proposed evaluation Index.