Fund Project Gansu Provincial Youth Science and Technology Fund Project 3981 people 2200546, 47, thermal insulation 3, cent; 0 different kinds of test variables above the sample in 46, heat 3,1. Guarantee; time is from the narrow temperature sample put the specified temperature The furnace is counted and kept hot for a predetermined period of time. Metallographic specimens were called 41 from 3 aqueous solutions etched in 13 optics from micro-mirrors and 5520 scanning electron microscopes were observed for 纟1 weaving and compositional changes in the heat treatment equipment. The experimental results and discussion of the jaw 1702 temperature-controlled 4K resistance furnace 2 Experimental results The influence of the 21-shaped variable on the original microstructure of the 27 alloy was gradually changed from the developed dendrite to the coarse equiaxed crystal and the short dendritic crystal. This is a secondary dendrite broken coarsening process, the secondary branch arm and the process of growing up with gold after 250 deformation. A large number of signals are generated within the grains, and the total area of ​​the product boundary increases, which increases the free energy of the system. In the subsequent air-cooling process, recovery and recrystallization occur to break the secondary dendrites. In order to reduce the free energy of the system, the secondary arms grew up. The greater the deformation, the greater the driving force for the above-mentioned evolution, the easier the recovery and recrystallization and the growth of the secondary dendrite arms.
2.2 Effect of isothermal temperature on microstructure of 7 alloys 22.1 Effect of temperature on microstructure After 20 deformation of 2 27 alloys at 420 and 30°C, the transition from short dendrites to large masses forms localized polygonal particles. , And distribution of some white appearance 21. As the isothermal temperature increases, the polygon particles, more, white darkening, disappeared at 440, 21. The temperature continues to rise, all the organization was granular, partial spheroidization. 460, when all spherical, the formation of fine spherical particles with an average particle size of 45,2,1. At this temperature, the solid phase rate is about 60, to 470, the organization is more rounded, the smaller the particle size is about 50 Heart, 24. In addition, it has been found that there are some small black dots in the polygon or spherical particles formed between 440 and 47,1, and there are small black dots in the polygonal particles, and there are large black dots in the center of the spherical particles. There are fewer black spots around, and as the temperature rises, the center chews on the sauce, and there are fewer and fewer black spots around. It can be inferred that the center is prone to juvenile breeding. 7. Planting mandarin ducks, mandarin ducks, and weird grasshoppers should be nbsp; The previous narratives can be used to make mountains. The higher the degree, the more organized, the formation of spherical particles, 460470C insulation 30min, The desired tissue for thixotropic semi-solid forming can be obtained.
With the increase of the holding temperature, the undeformed 2 people 27 alloy organization also gradually changed from the developed dendrite to the massive structure with small black spots dispersed. 232 The massive structure with white and dark spots 21 Black The grain boundaries of the smaller lumps become wider until an irregularly shaped phase and eutectic structure 2 are formed, indicating that non-dendritic granular structures cannot be obtained after isothermal treatment of the undeformed 2-man 27 alloy. Between 430 and 450, there are small black spots in the massive tissue, and the number changes from less to more, and then to more.
22.2 Compositional Changes and Organizational Analysis 7427 alloys were used as constituents of the constituent phases after 30 different temperature incubations.
42,1 The appearance of white appearance in the organization is due to the increase in solid solubility due to temperature increase. Although the content of 2 in the 2 phases is reduced, the black spots appearing in the 440 granular tissue are rich in the structure. The amount is as high as 34.13. This is due to the solidification of the + balance, and the formation of a solid solution desolvation. In this structure, the content of 1 is also considered to be a lower melting point!
Elementary eutectic structure. As the temperature progresses, the phase of the eutectic structure will enter. Increase the content of 1 and finally form a quasi-7-element eutectic structure. In addition, it was also found that the black structure at the grain boundary is the same as the black point component in the grain and belongs to the same type of organization. It can be seen that the isothermal temperature mainly affects the distribution of various elements in the constituent phases, and thus their color and morphology at higher temperatures are different.
After 30min of incubation, the temperature of the components of the constituent phases, the composition phase and the corresponding element contained white bright phase, white phase appearance, phase black phase, dark spots in the phase particles, dark spots in the phase particles, and phase 3 conclusions at 250, and follow. With the increase of the variables, the original structure of alloy 27 gradually evolved from the developed dendrites to coarse equiaxed and short dendritic crystals.
With the increase of isothermal temperature, the microstructure of the alloy changes from massive to granular and finally forms a spherical group. Weaving, deformation of the landscape looks more similar to the cabinet 2.1. However, after analysis, analysis of the 420 Baohou like black organization including grain boundaries and, the black point in the phase is 2,1 yuan eutectic organization, and 45,1 when the insulation is 21 Yuan eutectic structure. The reason why the zinc-rich white phase was not formed and was not granulated was because there was no deformation recovery and recrystallization-induced dislocations and polygonal grain boundaries.
2.3 Effect of Formal Variation on the Structure of Alloy 27 After the temperature 3,1, combined with 2,1, it can be seen that as the strain amount of the strain reaches 20, all become spherical particles. Compared with the 20-shaped variable, the 30 deformed particles have a smaller size and a good roundness. That is, the larger the deformation, the easier to obtain the ideal thixotropy. This is because the more refined and recrystallized the product, the finer the grain, the finer the finer particles. 32.27 The six golds in the small processing 1 have a large granularity, and the smaller the size, the better the granularity of the roundness. 2030 deformation of 460470, thermal insulation 30, can be obtained in an ideal thixoforming shape.
A two-dimensional eutectic structure is formed on the polygonal grain boundary formed by recovery and recrystallization at a low temperature, and a 21-element eutectic structure is formed at a high temperature. Because the eutectic structure has a relatively low melting point, it melts during the heat preservation process to form particles.
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Magnetostrictive level sensor is composed of three parts: probe rod, circuit unit and float. To measure, the circuit unit generates pulses of current that travel down the magnetostrictive line and generate a circular magnetic field. A float is arranged outside the probe rod, and the float moves up and down along the probe rod with the change of liquid level. The float generates a magnetic field at the same time because it is fitted with a set of permanent magnets. When the current magnetic field meets the float magnetic field, it produces a "twisting" or "return" pulse. The time difference between the "return" pulse and the current pulse is converted into pulse signals to calculate the actual position of the float and measure the liquid level.
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