Characterizing the Chemical Structure of Ti3C2Tx MXene by Angle-Resolved XPS Combined with Argon Ion Etching

Angle-resolved XPS combined with argon ion etching was used to characterize the surface functional groups and the chemical structure of Ti3C2Tx MXene. Survey scanning obtained on the sample surface showed that the sample mainly contains C, O, Ti and F elements, and a little Al element. Analyzing the angle-resolved narrow scanning of these elements indicated that a layer of C and O atoms was adsorbed on the top surface of the sample, and there were many O or F related Ti bonds except Ti–C bond. XPS results obtained after argon ion etching indicated staggered distribution between C–Ti–C bond and O–Ti–C, F–Ti bond. It is confirmed that Ti atoms and C atoms were at the center layer of Ti3C2Tx MXene, while O atoms and F atoms were located at both the upper and lower surface of Ti3C2 layer acting as surface functional groups. The surface functional groups on the Ti3C2 layer were determined to include O2−, OH−, F− and O−–F−, among which F atoms could also desorb from Ti3C2Tx MXene easily. The schematic atomic structure of Ti3C2Tx MXene was derived from the analysis of XPS results, being consistent with theoretical chemical structure and other experimental reports. The results showed that angle-resolved XPS combing with argon ion etching is a good way to analysis 2D thin layer materials.

Design of Distribution Equipment Monitoring System Based on Internet of Things and Multi-Agent

In order to improve distribution equipment reliability and emergency repair response speed, a distribution equipment monitoring system based on Internet of things and multi-agent is designed by building a hierarchical model. The system is based on the power Internet of things, which is divided into sensing layer, device layer and data center layer. The sensing layer realizes multi-source data acquisition through sensors and acquisition devices; the device layer deploys edge computing agents to realize device-level monitoring; and the data center layer deploys coordinating agents to realize system-level analysis. The dual-way communication is used to realize data transmission between up layer and down layer. The system has the characteristics of distribution, autonomy and multi-objective interaction, which can meet and adapt to the demand and development trend of intelligent operation and maintenance of distribution equipment.

Microstructure and Tensile Properties Anisotropy of 7xxx Ultra-Thick Plate

The microstructure，texture distribution and tensile property of 7xxx ultra-thick plate was investigated by optical microscopy (OM), scanning electron microscopy (SEM), electron back scattering diffraction (EBSD), transmission electron microscopy (TEM) and tensile tests. The results show that the microstructure, texture and tensile property were inhomogeneous along the thickness direction. A large number of sub-crystals remained on the surface of the thick plate and was accompanied by much recrystallization. Most of the structures were random texture, and the proportion of typical texture was low at the edge. For the center layer, there were also a lot of recrystallized grains and typical deformed texture along the β-fiber (Brass, S, and Copper) was observed. The 1/4 layer of the plate is a transition one, and had the lowest recrystallized fraction. From surface to center, precipitation phases within grains and grain boundaries gradually coarsen, mechanical properties reduced. At the same thickness, the tensile property showed appreciable anisotropy, the L direction was the highest and the S direction was the lowest.

The Effect of Deformation Strain on Texture Uniformity in Tantalum Sheet during Asymmetric Cross Rolling

Microstructure and crystallographic texture play an important role in the sputtering target properties. The effect of asymmetric cross rolling (ACR) and deformation strain during ACR on texture homogeneity is not clear. Thus, high-purity tantalum (Ta) plates were ACR to 60% and 87% reduction in thickness. Texture of the rolled Ta sheets in the surface and center layer are characterized via X-ray diffraction (XRD). The XRD results indicate that ACR is effective to weaken the texture gradient existing in the as-received Ta plate. Besides, more homogeneous texture distribution along the thickness can be obtained with the increasing strain during ACR process.

Evolution of microstructure and texture of ultra-thin non-oriented electrical steel manufactured by CSP

The evolution of the microstructure and texture of CSP thin-gauge non-oriented silicon steel was investigated by OM, XRD and EBSD. Results show: (1) the equiaxed surface grains with 28.13 µm average grains size accounted for 19.14% of through-thickness, while deformed band structure dominated the center layer and the other maintained at a composite structure with the first two. With the cold-rolled reduction rate enhancing to 91.15%, the stratification structure transformed into a complete fibrous structure. Annealing from 925 °C to 975 °C, the average grain size of the annealing plate similarly increased, which begins with 67.3 µm and ends at 80.58 µm. (2) The texture of the hot-rolled sheets mainly located at Cube and Goss texture, while with the cold-rolled process executing, the type and volume of texture change and finally stabilize at α fiber texture ({110}//RD) with the peak at {114}<110> at 91.15% reductions rate. The {411}<148> texture on the α* fiber line throughout maintained the strongest texture at different annealing temperatures. (3) The initial re-crystallization temperature is in the range of 600–620 °C, and the re-crystallization is roughly completed at 700 °C. Part of {411}<148> oriented grains nucleated at {411}<148> sub-grains originated from α fiber deformed structure, and the others nucleate at the grains boundaries of the deformed α fiber grains or in the inner of {111}<110> and {111}<112> grains. When the re-crystallization was accomplished at 750 °C, {411}<148> oriented grains are significantly larger than other oriented grains compared to 680 °C or the less. (4) Best magnetic properties were obtained at 975 °C with the B50 = 1.506 T and P10/400 = 16.19 W/kg.

The Effect of Different Annealing Temperatures on Recrystallization Microstructure and Texture of Clock-Rolled Tantalum Plates with Strong Texture Gradient

The texture and the bulk stored energy along the thickness direction were extremely inhomogeneous in the clock-rolled tantalum sheets with 70% reduction. Therefore, the effects of different annealing temperatures on the microstructure and texture distribution of tantalum plates through the thickness were investigated by X-ray diffraction (XRD) and electron backscatter diffraction (EBSD). The results showed that the occurrence of strong {111} recrystallization texture in the center layer can be attributed to the subgrains nucleation mechanism when annealed at the low temperature. Many subgrains with {111} orientation appeared in the center layer, due to its high stored energy and preferential nucleation sites of the {111} deformed matrix, and rapidly grew into the effective nucleus, resulting in the large {111} grain size and strong {111} texture after complete recrystallization. Contrarily, at the high temperature, high-angle grain boundaries had sufficient driving force to generate migration, due to the lack of recovery, and the growth time of recrystallized nucleus was much shorter, contributing to relatively uniform recrystallization microstructure and texture distribution along the thickness.

Effects of Annealing Temperature on Recrystallization Texture and Microstructure Uniformity of High Purity Tantalum

One hundred and thirty-five degree clock rolling significantly improves the texture homogeneity of tantalum sheets along the thickness, but a distinctly fragmented substructure is formed within {111} (<111>//normal direction (ND)) and {100} (<100>//ND) deformation grains, which is not suitable to obtain a uniform recrystallization microstructure. Thus, effects of different annealing temperatures on the microstructure and texture heterogeneity of tantalum sheets along the thickness were investigated by X-ray diffraction (XRD), electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM). Results show that the texture distribution along θ-fiber and γ-fiber is irregular and many large grains with {111} orientation develop during annealing at high temperature. However, low-temperature annealing can not only weaken the texture intensity in the surface and the center layer but also introduce a more uniform grain size distribution. This result can be attributed to the subgrain-nucleation-dominated recrystallization mechanism induced by recovery at low temperature, and moreover, a considerable decline of recrystallization driving force resulting from the release of stored energy in the deformation matrix.

Recovery and Recrystallization Behavior of Large Sized β Phase Grains in TC18 Titanium Alloy during Annealing Process

The manufacturing processes of TC18 titanium alloy bar takes about 10 times forging. During forging, the β phase grain experiences a series complicated process such as recovery, recrystallization and grain growth. Larger sized β phase grains can easily be formed under different conditions such as insufficient deformation or slow cooling rate during the forging process, which may affect the mechanical properties of TC18 bars. In order to find out the causes and elimination methods of large β grains, this paper used EBSD techniques to analyze the microstructure and texture of TC18 titanium bar at center layer, 1/2R layer and surface layer after the process of forging and heat treatment. Results show that a large portion of β grains experiences recovery and grain growth, while a minor portion of β grains only experiences recrystallization after α+β region heat treatment. Most β grains experience recrystallization, while for those β grains which are hard to be swallowed by recrystallized grains only experience recovery after β region heat treatment. Rather than eliminate the large sized β grains, it’s even easier for those β grains to grow up during annealing process under the condition of insufficient deformation.

Numerical Simulation of the LCP Hele-Shaw Flow Based on the Injection Molding Process

In order to broaden the application range of LCP, the simulation of the LCP Hele-Shaw flow in the square cavity was conducted. The temperature of the cavity was constant 300°C. In the simulation the Leslie-Ericksen and TIF theories were used. With this simulation results, we can predict the position of the flow front at any time during the whole injection process and grasp the change of the pressure field and the velocity field. The change of the pressure and the velocity fields were very slow, there was no distortion point in the whole flow field. In the layer near the wall, the directors arranged evenly according to the direction of the flow and in the center layer it was decided by the shear rate in the X-Y plane.

The Influence of Inhomogeneous Deformation on the Microstructures and Properties of Thick-Plate 7150 Alloy

The diversities and relations of microstructures and properties between the center and surface layer in thick-plate 7150 alloy were investigated by means of OM, TEM, SEM and tensile tests. The results indicated that the average width of elongated grains with fewer substructures in the center of hot-rolling thick plate is about 2 times larger than that in the surface layer. The coarser second phases are massed up at the grain boundaries of the center layer while those are crushed into smaller particles in the surface layer. By aging, the strengthening precipitates in the center are mainly GP zone and η' phase, while in the surface layer η' and η phases play the main roles. Consequently, the strength is about 80Mpa (15%) higher in the center than in the surface, with lower elongations (26% lower).