In order to explore the microstructure, texture, individual performance, and grain size characteristic evolution law during the process of multipass cold rolling, graded annealing process, the experimental design, research approach, and methodology were investigated using the equipment of optical microscope (OM), X-ray diffraction (XRD), electron backscattered diffraction (EBSD), and transmission electron microscope (TEM). The results show that a low interannealing temperature could strengthen the cubic texture after finished product annealing, and a high volume fraction of cubic texture components was subsequently obtained. In view of the nucleation advantage of cubic texture, the Cube-{001}<100> texture formation after annealing was promoted by the cold-rolled texture of Cu-{112}<111> and S-{123}<634>, which mainly depended on the decomposition of Cu and S textures, finally, they were consumed and transformed from Cu and S textures into a cubic texture. In addition, the dislocation configuration and corrosion pit density were clearly visible and distinctive in the observation space of aluminum foil.
The integrated gasification and combined cycle (IGCC), uses low rank coal (higher moisture and volatile contents and lower heating value) as fuel for gasification (e.g Texaco gasifier of Tampa electric with low ash coal) and convert the solid fuel into synthetic gas mainly consisting of CO and H2. During the storage of fresh low rank but highly reactive coals near the IGCC plants, the coals undergo drying and low temperature atmospheric oxidation which raises the temperature, reduces the moisture and eventually causes spontaneous ignition if the temperature rises above about 800 °C in the coal piles for bituminous and 500 °C for lignite coals. Thus it is of interest to understand the dewatering mechanism of the low rank lignite by drying samples using N2, CO2 and air (which represents partial oxidation) as drying mediums. Fundamental experiments were performed on dewatering of coal samples using thermo-gravimetric analysis (TGA) with different particle sizes and drying mediums. A wide range of drying temperatures from 100 to 225 °C with a step of 25 °C was investigated at a residence time of about 30 minutes. There are no significant differences among moisture weight loss curves for the three drying mediums. It was found that the lignite lost only 5% mass at about 100 °C. With further increase in temperatures most of the mass loss occurred within the temperature range of 120 to 170 °C. The maximum moisture release rate occurred for the temperatures between 125 °C and 140 °C and hence serves as the optimal temperature range for removing the moisture. When drying temperature was below 140 °C, highest moisture release rate occurred in N2 environment while for CO2 environment, optimal temperature rose beyond 140 °C. The structure of the dewatered lignite samples were further investigated through Scanning Electron Microscopy (SEM) studies. When experiments were repeated in air, ignition occurred and corresponding ignition temperatures were obtained. The larger particles reveal lower ignition temperatures.
In order to study the microstructure evolution rule of pure aluminum plates during different cold-rolled (CR) deformation degrees and annealing processes, samples with aCR deformation of 50~85%, heating rates of 60~100 °C/min and annealing at the target temperature of 350~500 °C were investigated. The microstructure, crystallite dimension and grain boundary characteristics were characterized by the methods of polarizing microscope (PM) and electron backscattered diffraction (EBSD). The results showed that the crystallite dimension of the initial state was 102 μm and ends up completely broken with an increase in the CR deformation degree. When the CR deformation increases to 85%, the deformed micro-bands were very small, with a band spacing of 5~10 μm. At this time, the grain distortion is more serious, there are more high-density grain defects, such as dislocations, and there is a high deformation of the storage energy, which is the energy preparation for the subsequent finished products to withstand the annealing process. The recrystallization fraction was higher with an increase in annealing temperature. After completed recrystallization, the grains showed an equiaxed shape. Orientation imaging and misorientation angle analysis showed that the red-oriented grains of the (001) plane, which had preferred nucleation, recrystallization and rapid grain growth. Final grains of the completed recrystallization are relatively coarse. Under the same deformation, the average crystallite dimension of the recrystallized grains decreases with an increase in annealing heating rate.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.