389 results about "Grain growth" patented technology

The invention relates to the technical field of hot galvanizing, and discloses an automobile hot galvanizing process parameter optimization method and system based on artificial intelligence, and the method comprises the steps: carrying out window division processing on initial cooling parameters, constructing a cooling rate matrix, and finely depicting heat exchange states of different cooling sections; the problem of insufficient cooling control precision under different cooling speed alternating conditions is solved, a microscopic image is combined to extract the grain main axis direction, calculate the mean value and range of included angles, generate a consistency index set and quantitatively describe the dispersion problem in the grain growth direction, the cooling speed and the consistency index are jointly matched, and a cooling speed structure offset matrix is constructed. The method comprises the following steps: identifying a space mutation region, accurately positioning abnormal coarse or abnormal arrangement positions of crystal grains, and finally screening target cooling parameters according to a cooling index value corresponding to an abnormal region to realize local adjustment of a cooling process, thereby reducing the abnormal growth rate of the crystal grains and improving the direction consistency of the crystal grains.

The invention belongs to the technical field of silicon nitride ceramic substrates, and particularly relates to a high-thermal-conductivity and high-breaking-strength silicon nitride substrate and a sintering method and application thereof. In order to simultaneously improve the thermal conductivity and the breaking strength of the existing silicon nitride ceramic substrate and ensure the stability and the consistency of the performance during the production of the silicon nitride substrate, the method comprises the following steps: coating the surface of a silicon nitride ceramic biscuit subjected to tape casting with isolation powder, carrying out nitrogen or air atmosphere glue removal treatment, and then sintering; in the sintering process, the cooling process is optimized, a multi-temperature heat preservation platform is arranged above the liquid phase conversion temperature, grain growth and grain boundary composition of the silicon nitride ceramic are regulated and controlled, grain size distribution of the silicon nitride ceramic is made to be more uniform, the grain boundary structure is made to be more optimized, and the heat conductivity coefficient and breaking strength of the substrate are remarkably improved. Meanwhile, the uniformity of a temperature field in the sintering furnace can be greatly improved through the sintering method, it is ensured that the product can reach the consistent performance standard in different areas, and the stability and reliability of the product are improved.

The invention discloses a preparation method of thermal shock resistant magnesium aluminate spinel transparent ceramic, and belongs to the technical field of ceramic materials. The preparation method comprises the following steps: (1) synthesizing crystalline MgAl2O4 nano powder by adopting an additive-free hydrothermal method; (2) depolymerizing the powder, performing water-based gel casting to prepare a green body, and performing staged debonding treatment on the green body; (3) carrying out two-step vacuum presintering on the green body; (4) carrying out hot isostatic pressing densification treatment in a subgrain growth temperature region of 1380-1420 DEG C; and (5) carrying out annealing treatment on the densified ceramic. High-purity crystalline powder is synthesized through an additive-free hydrothermal method, grain boundary impurities are eliminated, and the intermediate infrared transmittance is remarkably improved; by combining the synergistic effect of optimized two-step pre-sintering and hot isostatic pressing in a sub-grain region, precise refinement of the grain size is realized; and finally, the bending strength, the fracture toughness and the critical thermal shock temperature difference of the material are greatly improved under the strengthening mechanism of ultrafine grains and defect-free grain boundaries.

The invention discloses a preparation method of a superfine WC-Co hard alloy. 89.8-90% wt of superfine tungsten carbide, 9% wt of superfine Co powder and 1-1.2% wt of composite additive chromium carbide and vanadium carbide are adopted; wherein the weight ratio of chromium carbide to vanadium carbide is 1 / 2; ball-milling the raw materials to obtain a mixture; and the pressed blank is subjected to a specific oscillation pressure and rapid cooling sintering process, the contact form and interface state among particles are improved, the density of the hard alloy is improved, WC grain growth is inhibited, flowing of binding phase Co is promoted, the structure and mechanical properties of the alloy are remarkably improved, and the nanocrystalline WC-Co hard alloy with high strength and high density is obtained.

The invention relates to a high-hardenability gear steel bar for a new energy automobile and a manufacturing method of the high-hardenability gear steel bar. The high-hardenability gear steel bar comprises the following chemical components in percentage by mass: 0.17-0.25% of C, less than or equal to 0.37% of Si, 0.50-0.90% of Mn, 0.85-1.25% of Cr, less than or equal to 0.025% of P, less than or equal to 0.030% of S, less than or equal to 0.30% of Cu, 0.02-0.06% of Ti, 0.02-0.05% of Al, less than or equal to 0.30% of Ni, 0.15-0.45% of Mo, 0.0005-0.0020% of B, 0.020-0.080% of Nb, less than or equal to 0.0030% of Ca, 0.0090-0.0150% of N, less than or equal to The production and manufacturing process comprises the steps of converter treatment, external refining, vacuum degassing, continuous casting, continuous rolling, shearing or saw cutting, stack cooling and finishing flaw detection. According to the invention, fine Nb (C, N) and (Nb, Ti) (C, N) particles are precipitated by microalloying Nb and Ti, the growth of crystal grains is effectively inhibited, and meanwhile, the hardenability of the material is improved by adding a proper amount of B element. According to the invention, Nb, Ti and B are adopted for composite microalloying at the same time, so that the fine-grain and high-hardenability gear steel material is obtained.

The invention belongs to the technical field of photovoltaic solar materials, and particularly relates to a high-conversion-efficiency perovskite precursor material and a preparation method thereof. The high-conversion-efficiency perovskite precursor material is composed of phenyl ammonium cesium composite cations, metal halide, an additive, a nuclear auxiliary agent and a solvent. By compounding phenylethyl ammonium iodide and cesium iodide, phenylammonium and cesium cations are introduced into perovskite crystal lattices, organic-inorganic balance of the material is optimized, phenylammonium promotes formation of a quasi-two-dimensional structure, and damp-heat stability is enhanced; cesium ions fill A-site gaps, so that crystal lattices are tighter, and the thermal stability and the photoelectric conversion efficiency are improved; the synergistic matching addition of the metal halide realizes band gap regulation and control and spectrum matching, and quaternary ammonium salt adjusts nucleation and grain growth, so that a uniform film structure is ensured, and defects are reduced; and guanidine salt passivates defects after crystal growth, stabilizes crystal lattices, and improves charge life and device efficiency.

The invention belongs to the technical field of lithium ion battery materials, and discloses a preparation method of a high-first-effect small-particle single-crystal ultrahigh-nickel ternary positive electrode material. The method comprises the following steps: firstly, uniformly mixing an ultrahigh nickel ternary precursor with a lithium source and a tungsten source, performing mechanical densification and pressing to obtain a blocky solid, and then performing four-section program temperature control calcination to obtain a target material. The interface fusion resistance of single crystal growth can be reduced through mechanical densification; a part of the tungsten element forms a Li2WO4 coating layer, and a part of the dopant phase replaces Ni < 2 + >, so that grain growth can be inhibited, a crystal structure can be stabilized, and the first effect is improved; and the microstructure of the material can be accurately regulated and controlled through four-section temperature-controlled calcination. Through a coating-doping-single crystallization synergistic strategy, the electrochemical performance of the material in liquid and sulfide-based all-solid-state batteries is remarkably improved, the process is controllable, and the application prospect is wide.

The invention discloses a fine-grain tungsten-nickel-iron composite material and a low-temperature sintering preparation method thereof. The composite material takes W as a hard phase, Ni and Fe as binding phases, Y2O3 as a particle reinforcement phase and a grain growth inhibitor, and Sn as an alloy element and a sintering fluxing agent. The preparation method comprises the following steps: 1, carrying out carbon heat and hydrogen reduction on WO3, NiO, Fe2O3 and nano carbon black to obtain composite powder; 2, carrying out wet grinding with Sn and Y2O3 powder, and drying; 3, compression molding; 4, degreasing and pre-sintering treatment; and 5, low-temperature liquid-phase sintering. According to the composite material, low-temperature liquid-phase sintering is achieved by introducing the Sn element and the Y2O3, the wettability and the interface bonding force between W crystal grains and a bonding phase are improved, and the composite material with uniform components and refined crystal grains is obtained; the preparation method improves the tensile strength, microhardness and room temperature plasticity of the composite material, and is suitable for the fields of aerospace, national defense and military industry, nuclear industry, electronic information, metallurgy and the like.

The invention belongs to the field of hard alloy materials, and provides a modified high-performance non-magnetic hard alloy and a preparation process thereof. The surface of a WC particle is chemically plated with a Ni-P-B-Cr-Cu amorphous shell layer, and a binding phase is converted into Ni3P and Ni3B nanophase through two-stage sintering. The WC alloy comprises the following components in parts by weight: 85-95 parts of WC, 12-25 parts of a binding phase and 0.5-1.4 parts of a grain growth inhibitor, the nanophase accounts for 35-50% of the volume of the binding phase and 35-50% of the total volume of the binding phase, and the grain size is 80-125 nm; the average grain size of WC is 0.6-1.0 [mu] m; and the thickness of an interface P enrichment layer is 8-15 nm (the coverage rate is 85-95%). Through interface engineering and controlled crystallization from amorphous to nanocrystalline, the relative magnetic conductivity is 1.001-1.015, the hardness HRA is 90.5-93.0, the strength TRS is 2.2-3.0 GPa, the toughness KWP is 300-450 N / mm, and the magnetic saturation strength is 0.02-0.15 T. The problem of decoupling of the magnetic property and the mechanical property of a traditional non-magnetic hard alloy is solved, and the non-magnetic hard alloy is suitable for magnetic sensitive environments such as semiconductor equipment, precise measurement, MRI tools and oil service logging.

The invention discloses a pyrochlore structure high-entropy ceramic solidified body material as well as a preparation method and application thereof, and belongs to the technical field of nuclear waste solidification. The preparation method of the high-entropy ceramic solidified body material with the pyrochlore structure comprises the following steps: weighing raw material powder of La2O3, Nd2O3, Sm2O3, Gd2O3, Eu2O3 and ZrO2 according to the proportion in (La0. 2Nd0. 2Sm0. 2Gd0. 2Eu0. 2) 2Zr2O7; the weighed raw material powder is subjected to ball milling treatment, and ball-milled powder is obtained; under the inert gas atmosphere, the ball-milled powder is subjected to heat treatment, and heat-treated powder is obtained; and carrying out spark plasma sintering on the heat treatment powder to obtain the pyrochlore structure high-entropy ceramic solidified body material. The powder is treated by using a heat treatment technology, so that the powder is homogenized, a pyrochlore phase is formed, grain growth is more favorably inhibited, a fine grain structure is obtained, and the irradiation stability and the mechanical property of the pyrochlore material are improved.

The invention discloses a method for improving the thermal stability of a gradient nanocrystalline structure, and belongs to the technical field of metal material processing. According to the method, Mg-RE series alloy is used as a matrix, a matrix alloy ingot is heated for solution treatment, surface strengthening is carried out after water quenching and cooling, a gradient nanocrystalline layer is formed on the surface layer of an alloy sample, finally, the alloy sample is transferred into an aging oven for low-temperature aging, and cooling is carried out, so that the magnesium alloy is obtained. According to the method, the thermal stability of the magnesium alloy gradient nanocrystalline is improved through a synergistic strategy of component design and low-temperature aging, so that the grain growth rate of Mg-RE alloy gradient nanocrystalline structures treated by various different surface strengthening methods in a high-temperature environment can be remarkably reduced; the core bottleneck that a traditional magnesium alloy gradient nanocrystalline material is poor in thermal stability and single in applicable surface treatment method is solved; and the process does not need special equipment, can be seamlessly connected with various existing magnesium alloy surface strengthening production lines, and is low in process cost, simple and convenient to operate and easy to industrially popularize.

The present invention discloses a twinned and dispersion-strengthened WC-Ni-based cemented carbide and its preparation method. The alloy is composed of a hard phase component WC, a bonding metal Ni, and supersaturated composite grain growth inhibitors Cr3C2 and VC. The WC hard phase in the alloy is composed of irregular grains with an average grain size of less than 0.5 μm and dispersed small plate-like grains. The typical morphological characteristics of the fine plate-like WC grains in the polished cross-section of the alloy are long strips with an average length of less than 2.2 μm and an average width of less than 0.5 μm. Nano-dispersed phases exist in the Ni-based bonding phase solid solution matrix in the alloy. The present invention uses unsaturated carbon nano-WC powder as raw material, and through ultrafine grain strengthening of the hard phase, strengthening of dispersed fine plate-like crystals, and nano-dispersed phase strengthening of the bonding phase, the alloy is given high hardness, high toughness, and high strength.

The application discloses a preparation of a low-temperature and low-bombardment transparent conductive film and application of the transparent conductive film in a perovskite / crystalline silicon laminated solar cell. The composite film is prepared by magnetron sputtering of TCO ceramic targets with different doping ratios at room temperature. ‑5 The composite transparent conductive oxide film is obtained by adjusting the sputtering pressure and power of the TCO film with different doping ratios and adjusting different growth modes, and the composite transparent conductive oxide film has a low-temperature and low-bombardment property. The lower layer of the composite transparent conductive oxide film is in a columnar crystal growth mode, and the upper layer is in an equiaxed large-grain growth mode. The composite transparent conductive oxide film can be applied in a perovskite / silicon laminated solar cell, can promote the vertical and horizontal transmission capacity of carriers in a TCO transparent electrode, promotes the effective collection and transmission of carrier charges, and thus a high-efficiency perovskite / silicon laminated solar cell is obtained.

The invention belongs to the technical field of refractory materials, and particularly relates to a mullite refractory material with high mechanical property and a preparation method thereof. The mullite refractory material is prepared by taking coal gangue, bauxite and fly ash as raw materials, and the three industrial solid wastes are converted into the refractory material with high additional value, so that the concept of circular economy is met. According to the invention, coal gangue, bauxite and fly ash are used as raw materials, CaF2, V2O5 and lanthanide rare earth oxide are used as sintering aids, the problems of insufficient mechanical properties and overhigh sintering temperature of the mullite refractory material prepared by purely using coal gangue, bauxite and fly ash as raw materials are solved, and the performance of the mullite refractory material can be greatly improved. CaF2 and V2O5 promote substance transport and grain growth, and rare earth oxide inhibits excessive growth of grains. The balance of'promotion 'and'inhibition' is favorable for forming a compact, fine, uniform and interlaced mullite crystal network, and meanwhile, the mullite crystal network has high strength and good toughness.

The invention discloses a high-temperature high-strength zirconium alloy and a manufacturing method thereof and belongs to the field of nuclear engineering materials. The high-temperature and high-strength zirconium alloy comprises the following components in percentage by weight: 1%-10% of Sn, 0.1%-1% of O, 0.01%-3.5% of Al, 0.01%-0.5% of Si and / or 0.01%-0.5% of Ge, and the balance of Zr and inevitable impurities. In the high-temperature and high-strength zirconium alloy, Si and / or Ge can form a precipitated phase which is thermodynamically stable at a high temperature, an alpha-Zr grain boundary is pinned at the high temperature while grain refinement is promoted, solid-state phase change and grain growth in a zirconium alloy matrix at the high temperature are inhibited, and the alloy keeps good mechanical property and structure stability at the high temperature.

The invention relates to the field of high-temperature refractory materials, and discloses a fusion casting method for improving the performance of an AZS octagonal cylinder checker brick, which comprises the following steps: mixing and smelting main raw materials and a composite additive (containing surface-modified nano YAG particles and a rare earth core-shell structure) to obtain a high-purity melt in an inert atmosphere; staged vibration pouring is conducted in the vacuum environment, low-frequency vibration and high-frequency vibration are combined, and the melt filling compactness is improved; an alternating magnetic field is coupled in the gradient cooling process, grain growth is directionally regulated and controlled, and thermal stress is released; and annealing treatment is combined with a surface densified coating, so that the defects are further eliminated, and the erosion resistance is enhanced. According to the invention, through linkage of technologies such as strengthening of a crystal boundary by the composite additive, collaborative optimization of a structure by vibration-magnetic field, inhibition of phase change by a gradient process and the like, the material has excellent thermal shock resistance, high-temperature strength and molten medium corrosion resistance, and is suitable for harsh working conditions such as glass kilns and metallurgical high-temperature equipment.

According to the preparation method of the free-cutting lead brass alloy, trace elements such as tellurium, cobalt, samarium and selenium are added into lead brass, the tellurium, the selenium and the like can easily form low-melting-point compounds with other elements, grain growth can be inhibited, dispersed distribution of fine lead particles is promoted, stress concentration is reduced, and the cutting performance is improved; by adding cobalt, samarium and the like, grain refinement is facilitated, distribution and forms of selenium, tellurium and other elements are changed, alloy fluidity is promoted, dispersed distribution of lead and the like is promoted to be more uniform, the cutting performance is further improved, in addition, dissolution of lead can be inhibited through the passive film layer, the environment-friendly performance is improved, and harm caused by dissolution of lead is reduced.

The invention discloses a high-performance wear-resistant steel ball production process based on powder metallurgy, and aims at solving the problems that a traditional cast steel ball is poor in wear resistance, the powder metallurgy process is low in efficiency and the like, breakthrough is achieved through multi-phase collaborative design and electric field activated sintering, medium-carbon low-alloy steel is used as a matrix, nano TiC (dispersion strengthening) and h-BN (self-lubricating) are compounded, and the high-performance wear-resistant steel ball production process based on powder metallurgy is obtained; a gradient structure (high Cr / high TiC on the surface layer strengthens wear resistance, and low Cr / low TiC on the core part ensures toughness) is constructed; the electric field activated sintering technology is adopted for low-temperature rapid densification (the density is larger than or equal to 99.2%), and grain growth is remarkably inhibited. The technology breaks through the hardness-toughness contradiction, is suitable for high-impact and high-wear extreme working conditions, and provides a low-cost solution for localization of high-performance wear-resistant materials.

The invention discloses a preparation method of a MgO-MgA12O4-ZrO2 nano ceramic eutectic composite material. The preparation method comprises the following steps: S1, preparing powder; s2, flash firing preparation; and S3, high-temperature melting preparation. According to the invention, two technologies of flash sintering and high-temperature melting are combined, the problems of high sintering temperature, easy growth of crystal grains, difficult densification and the like of the traditional eutectic ceramic are solved, and an excellent composite material with a nanoscale eutectic structure is finally obtained; a nanocrystalline blank obtained through flash sintering is crushed and then subjected to high-temperature melting, microdefects and air holes possibly existing in the flash sintering blank are eliminated, the chemical components and the microstructure of a final product are more uniform, and compared with traditional selective laser melting, the method is more convenient and faster to implement and lower in cost.

The present invention discloses a method for automatic identification and precise quantitative characterization of grains based on metallographic images, which belongs to the technical field of material microscopic analysis. The present invention uses closed operations, bottom-hat transformations, thresholds and other image processing methods to reduce noise and extract images, and uses a watershed segmentation algorithm based on markers to segment the grains of the image. Compared with existing grain statistical methods, this method has the characteristics of high efficiency, accuracy and objectivity, and uses an eight-neighborhood connectivity check method to mark each individual grain. Finally, each grain is quantitatively analyzed to know the maximum area, average area, area distribution and grain size of the grain. The above-mentioned grain quantification data can provide a reference for the mechanical property analysis of metal materials, and can track and quantitatively analyze the grain growth of long-term overheated metal parts.

The invention relates to the technical field of magnesium alloys, in particular to a low-density, high-modulus and ultrahigh-strength magnesium-based composite material and a preparation method thereof.The preparation method comprises the steps that SiC reinforcement particles are pretreated; the raw materials are proportioned according to the mass percent of the components of the magnesium alloy; melting pure magnesium, sequentially adding alloy elements, uniformly stirring, cooling to a semi-solid temperature interval, adding the pretreated SiC reinforcement particles, and casting in a preheating mold to solidify, so as to obtain a magnesium-based composite material cast ingot; the cast ingot is sequentially subjected to solution treatment and extrusion forming; carrying out secondary solution treatment on the magnesium-based composite material bar subjected to extrusion forming; and performing rotary swaging deformation and intermediate annealing treatment on the magnesium-based composite material bar subjected to secondary solution treatment to obtain the ultrahigh-strength magnesium-based composite material. Therefore, the problems that in the prior art, magnesium alloy is insufficient in strength and modulus, a magnesium-based composite material easily generates casting defects and is difficult to deform at room temperature, and the performance of the material is weakened due to grain growth during high-temperature deformation are solved.

The present invention belongs to the technical field of metal material casting, and specifically relates to a method for preparing large-sized high-purity copper ingots. The present invention provides a casting process using a short crystallizer and a ring-shaped water baffle, which enhances the water cooling effect, enables the ingot to cool down faster, and prevents grain growth, thereby obtaining an ingot with a uniform and fine structure. The method for preparing the ingot with a uniform and fine structure provided by the present invention has good operability, high production efficiency, low production cost, and can achieve industrialized mass production.

The invention relates to the technical field of soft magnetic ferrite materials, in particular to a preparation method of a high-permeability soft magnetic ferrite core material, which comprises the following steps: firstly, preparing FeSiCrBCu soft magnetic alloy powder with uniform components and controllable particle size through a single-roller quenching and hydrogen decrepitation process, and laying a structural foundation for excellent magnetic performance; and then a mechanical stirring-ultrasonic synergistic coating technology is utilized, so that the ferrite precursor uniformly coats the alloy powder, an effective core-shell structure is formed, and solid-phase reaction and crystal grain uniform growth during sintering are promoted. Besides, a multi-task deep learning model (MTL-DL) based on transfer learning is adopted to carry out multi-objective collaborative optimization on the sintering process, accurately match and dynamically adjust key parameters, and accurately regulate and control the material densification process, the grain size and the phase distribution on the microcosmic level, so that the problem that the microstructure and component uniformity are difficult to accurately control in the prior art is solved; therefore, the problems of poor material performance and high power loss are solved.

The invention provides a manufacturing method of a hard alloy for a hard rock cutting pick, which relates to the field of alloy preparation and comprises the following steps: step 1, preparing raw material powder for preparing the hard alloy for the hard rock cutting pick according to the proportion of raw materials; 2, mixing the raw material powder in the step 1 to obtain mixed powder; 3, putting the mixed powder obtained in the step 2 into a lower mold, and pressing on a press machine to obtain a pressed blank; step 4, sintering: primary sintering: putting the pressed green body into a first sintering furnace, and sintering at a first preset temperature; secondary sintering: putting the green body subjected to primary sintering into a second sintering furnace, and sintering at a second preset temperature; and 5, the hard alloy block obtained after secondary sintering is subjected to finish machining treatment according to the design size of the hard alloy part of the hard rock cutting tooth. According to the method, double-temperature-zone sintering is conducted, impurities / stress is removed through primary sintering (protective atmosphere), and grain growth is precisely regulated and controlled through secondary sintering (vacuum).

The invention discloses a bismuth ferrite-based ceramic material with low energy consumption and high energy storage and a low-temperature rapid sintering preparation method of the bismuth ferrite-based ceramic material, a flash sintering technology is applied to 0.55 BiFeO3-0. 4SrTiO3-0.05 NaNbO3 (BFST-0. 05NN) ceramic, on one hand, the component of 0.6 BiFeO3-0. 4SrTiO3 is close to a morphotropic phase boundary (MPB) to provide high polarization, and the introduction of NaNbO3 improves the structure disorder and promotes the relaxation behavior, so that the energy storage efficiency is improved; on the other hand, by optimizing the electric field (100-250 V / cm) and the flash sintering time under the fixed current density (40 mA / mm < 2 >), reactive densification can be achieved at the very low temperature and within the ultra-short time, and compared with traditional solid sintering, the furnace temperature is reduced by nearly 500 DEG C; flash sintering can realize densification of the ceramic, inhibit grain growth of the ceramic, refine a grain structure, inhibit volatilization of volatile elements and inhibit leakage conductance current at the same time, the lead-free bismuth ferrite-based ceramic with high breakdown and high energy storage and excellent ferroelectric, piezoelectric and energy storage performance is obtained, and green development and high energy storage are realized at the same time.

According to the low-shrinkage 3D printing zirconia ceramic and the preparation process thereof, photosensitive polyimide is selected, the photosensitive polyimide has an imine ring and a photosensitive group on a macromolecular chain and has the advantages of excellent photosensitivity, thermal stability, low volume shrinkage and the like, a photoinitiator does not need to be added into a product system, and the preparation process is simple. Curing can be directly completed under ultraviolet irradiation, and the problems of ceramic shrinkage, cracking and the like caused by volatilization or decomposition of a photoinitiator in a workpiece during degreasing are avoided; the ratio of the dispersing agent to the plasticizer in the product system is optimized, the viscosity of the slurry is reduced, the solid content is increased, the shrinkage rate after sintering is reduced, and the flowability and the printing precision of the slurry are ensured. Besides, by combining a flash sintering treatment process, grain growth coarsening is inhibited, a nanoscale compact structure is realized, and internal defects are reduced, so that the zirconia ceramic prepared by the method has the advantages of no defect, compact structure, smaller grain size (smaller than 1 mu m), excellent fracture toughness and higher relative density.

The invention provides a sheathing extrusion preparation method of powder metallurgy titanium alloy, and relates to the technical field of powder metallurgy titanium alloy preparation. The preparation method comprises the following steps: filling titanium alloy powder into a titanium sheath which is consistent with raw material components, and improving the filling density and the bonding strength of the powder by adopting a vibration powder filling and heating degassing process; then, through vacuum low-temperature presintering, it is ensured that powder particles are effectively combined, and grain growth is avoided; and finally, the pre-sintered blank is subjected to extrusion forming, the organization structure of the material is greatly improved, the compactness of the material is improved, full compactness is achieved, the fine-grain structure is guaranteed, and the fine-grain, high-strength and high-plasticity titanium alloy target profile is obtained. By means of the method, production of the high-performance titanium alloy profile in the complex shape can be achieved, multiple steps in a traditional technology are reduced, the production efficiency is remarkably improved, the manufacturing cost is reduced, and the method has important significance on application and popularization of the powder metallurgy titanium alloy profile.

The invention provides a cold machining manufacturing method of an ultra-fine grain seamless steel pipe. The method comprises the following steps: firstly, selecting a low-alloy structural steel billet with specific components, which comprises C, Si, Mn and microalloy elements of Nb, V and Ti, and heating, perforating and hot-rolling to prepare a pierced billet; and then multi-pass cold deformation treatment is carried out, 5-8 times of cold drawing or cold rolling is carried out on the pierced billet, the deformation of each pass is not lower than 30%, the cold drawing or cold rolling is carried out at the room temperature at the specific speed, and natural cooling is carried out between the passes. Recrystallization annealing is carried out after each pass of cold deformation, heat preservation is carried out for 1-2 hours at the temperature of 650-750 DEG C, and then controlled cooling is carried out. And finally, a finished product is obtained through straightening, head and tail cutting and nondestructive testing. According to the method, through cyclic cooperation of multi-pass cold deformation and recrystallization annealing and the effect of synergistically inhibiting grain growth of microalloy elements, the internal structure of the steel pipe is fully refined and homogenized, and then the comprehensive mechanical properties of the strength and toughness of the finished seamless steel pipe are remarkably improved; and meanwhile, the technological process is stable and controllable, and the product surface quality is excellent.

The invention discloses a processing method for solving grain growth in a solution treatment process of a high-temperature alloy, which comprises the following steps of: 1, obtaining a basic bar by adopting a hot working mode, specifically, carrying out forging cogging on a steel ingot, then carrying out hot working on the steel ingot through a fast forging machine or a rolling mill to obtain the required basic bar, and reserving a certain deformation amount; 2, stress relief annealing is conducted on the basic bar obtained in the step 1, and water cooling is conducted immediately after heat preservation is completed; 3, the bar obtained in the step 2 is subjected to cold drawing; and 4, the finished bar obtained after cold drawing is subjected to solution treatment. According to the method, firstly, residual cold deformation of the bar in the hot working process is eliminated through high-temperature stress relief annealing, then the bar reaches the specified size through cold drawing machining, the cold deformation of the bar is larger than critical deformation, finally, after standard solution treatment, grain structures of all parts of the bar are uniform, and abnormal growth of grains does not exist. The process has the advantages of environmental protection, convenience, flexibility and low cost.

The invention discloses an amorphous nanocrystalline magnetic material and a preparation process thereof, and relates to the technical field of magnetic materials, the amorphous nanocrystalline magnetic material comprises the following components by weight: 70-85 parts of raw material iron, 5-10 parts of raw material silicon, 5-12 parts of raw material boron, 0.5-3 parts of raw material niobium, 0.1-2 parts of raw material molybdenum, 0.1-1 part of raw material copper, and the balance trace elements. According to the amorphous nanocrystalline magnetic material and the preparation process thereof, the material simultaneously meets high saturation flux density, low loss and excellent thermal stability, in addition, a double-roller quenching method and a rapid solidification and low-temperature annealing process are combined, overgrowth of crystal grains is avoided, the high-frequency stability and mechanical strength of the material are ensured, the process is simple, the cost is low, and the method is suitable for industrial production. The method is suitable for industrial production.