2832 results about "Grain boundary" patented technology

The invention discloses a zinc coating shedding performance detection method and system, particularly relates to the technical field of metal surface treatment quality detection, and is used for solving the problems of high misjudgment rate and insufficient detection precision caused by coating surface pseudo defect interference in the existing method. The method comprises the following steps: synchronously acquiring a multispectral reflection image and three-dimensional morphology data of the surface of a zinc coating through an industrial vision imaging device, extracting grain boundary distribution information based on multispectral data, and identifying radial pseudo defects in combination with a curvature manifold geodesic line energy gradient direction of the three-dimensional morphology; and further performing micro-crack topology analysis and grain boundary spatial correlation verification on the candidate region, eliminating texture interference and grain boundary overlapping regions, and finally outputting a high-confidence fall-off defect detection result, so that the identification capability of real defects under a complex galvanized surface is remarkably improved, and the method is suitable for automatic detection requirements of a high-speed continuous production line.

The invention relates to a neodymium-iron-boron magnet which comprises main-phase crystal grains, a thin-layer crystal boundary phase and a triangular-area crystal boundary phase. Grain boundary phase distribution of a triangular region in the neodymium-iron-boron magnet meets the condition that S1 / S is greater than or equal to 0.057 and less than or equal to 0.073 The neodymium-iron-boron magnet comprises R, M, M1, Co, B and T; r is selected from one or more of Nd, Pr, Ho, Ce, Gd, Dy and Tb; m is selected from one or more of Al, Cu and Ga; m1 is selected from one or more of Ti, Zr, Nb, W and V; t is selected from Fe and other impurity elements; the content of R in the neodymium-iron-boron magnet is 28-32 wt%, and the content of M1 is 0.4-1.0 wt%; the triangular grain boundary phase comprises an R-T-M-Co phase, and the content of Co in the R-T-M-Co phase is 6.2 to 10.4 at%. The neodymium-iron-boron magnet provided by the invention has the advantages that the main phase grain roundness is high, the area proportion of the thin layer grain boundary phase is reduced, the area proportion of the triangular region grain boundary phase is increased, the atomic percent of Co in the R-T-M-Co phase formed in the triangular region grain boundary phase is increased, and the magnet has relatively high coercive force and squareness.

The invention relates to a neodymium-iron-boron magnet with high residual magnetism and high coercive force, and the neodymium-iron-boron magnet comprises R2T14B main phase grains and a grain boundary phase A, the neodymium-iron-boron magnet comprises R, M, B and Fe, R comprises RL and RH, RL comprises at least one of Pr, Nd, La, Ce and Y, RH comprises at least one of Dy, Tb, Gd and Ho, M comprises Co, Cu and optional M ', and M' comprises one or more of Cr, Ni, Ga, Al, Zr, Nb and Ti; in the grain boundary phase A, the content of R is 29-55 at%, the content of Co is 3-7 at%, and the content of Cu is 7-20 at%. The neodymium-iron-boron magnet provided by the invention is low in impurity element content, the diffusion depth of heavy rare earth elements is effectively improved, and the neodymium-iron-boron magnet has high coercive force and high residual magnetism.

The disclosure provides a modified tin-phosphor bronze alloy and a preparation method thereof. The modified tin-phosphor bronze alloy comprises the following elements in percentage by mass: 4.0-10 wt % of Sn, 0.01-0.3 wt % of P and the balance of Cu and inevitable impurity elements, the average grain size of the modified tin-phosphor bronze alloy is 1-3 μm, the grain size is in normal distribution, and the standard deviation of the grain size is below 0.8 μm; the proportion of the total low-CSL grain boundary in the modified tin-phosphor bronze alloy in the whole grain boundary is 66-74%, and in the total low-ΣCSL grain boundary, the ratio range of (Σ9+Σ27) / Σ3 is (0.12-0.23):1. The modified tin-phosphor bronze alloy of this disclosure enables a finished alloy can give consideration to both tensile strength and excellent bending performance.

The invention discloses a rock crack evolution numerical simulation method based on data analysis, and relates to the technical field of rock mechanics engineering numerical simulation, and the method comprises the following steps: S1, obtaining microstructure data of a target rock, including a CT scanning image, an SEM image and mineral energy spectrum data; and S2, constructing a spatial distribution dynamic mechanical parameter field based on the microstructure data. According to the rock crack evolution numerical simulation method based on data analysis, a dynamic mechanical parameter field driven by a microstructure is constructed, so that the inherent defect that rock is simplified into a homogeneous material in a traditional method is overcome; microscopic characteristics such as mineral hardness gradient, grain boundary strength distribution and pore morphology are effectively quantified into an elastic modulus field, a tensile strength field and a fracture energy field which are spatially distributed, so that the numerical prediction of crack initiation and expansion truly reflects the inherent heterogeneity of the rock for the first time.

The invention discloses a neodymium-iron-boron magnet, which comprises main phase crystal grains, a thin layer crystal boundary phase and a triangular region crystal boundary phase, and is characterized in that the neodymium-iron-boron magnet comprises 28 to 33 weight percent of R, 0.84 to 0.94 weight percent of B, 0.05 to 1 weight percent of Co, 0.05 to 0.55 weight percent of Cu, 0.3 to 0.6 weight percent of Ga, 0 to 0.55 weight percent of M2, 0.1 to 0.6 weight percent of M3, 66 to 70 weight percent of Fe and the balance of Fe, wherein R is a rare earth element and at least comprises PrNd; the triangular region grain boundary phase comprises an R6T13M1 phase, the element M in the R6T13M1 phase is selected from any two or more elements of Al, Cu, Ga, Ti, Sn and / or Zr, and the element T comprises Fe and / or Co; the sum of the areas of the R6T13M1 phases in the microscopic structure cross section of the neodymium-iron-boron magnet accounts for 5.2%-8.4% of the area of the microscopic structure cross section. The rare earth permanent magnet with high residual magnetism, high coercive force and good squareness consistency is obtained under the condition that no heavy rare earth is added or a small amount of heavy rare earth is added.

The invention discloses a production method of a high-performance sintered neodymium-iron-boron magnet. The production method comprises the steps of rapid quenching flaking, hydrogen decrepitation mixing, magnetic field forming, multi-stage treatment and composite coating. A nanocrystalline sheet is prepared through a rapid quenching technology, and uniform distribution of a grain boundary phase and rare earth elements is achieved through hydrogen decrepitation and material mixing; forming in a strong magnetic field and applying high pressure to improve the orientation degree; through high-temperature sintering, medium-temperature annealing and low-temperature aging treatment, magnet densification, grain boundary phase reconstruction and a magnetic domain structure are optimized; and finally, the corrosion resistance is improved by adopting a composite coating. The high-performance sintered neodymium-iron-boron magnet produced by the method comprises a main phase alloy, a grain boundary phase additive and a rare earth supplementary phase. Through low-oxygen nanocrystal preparation, grain boundary coordinated regulation and green process integration, compatibility of high performance, low cost and environmental protection is realized, and sustainable development of the rare earth permanent magnet material is promoted.

The invention relates to high-performance low-cost microalloyed steel for an automobile I-shaped front axle and a preparation method of the microalloyed steel, and belongs to the technical field of materials. The steel comprises the following chemical components in percentage by weight: 0.20 to 0.60 percent of C, 0.2 to 1.0 percent of Mn, 0.1 to 0.5 percent of Si, 0.6 to 1.2 percent of Cr, 0.01 to 0.10 percent of Nb, 0.01 to 0.06 percent of Mo and the balance of Plt, 0.01%, Slt; 0.01%, Olt; 0.0040%, and the balance being iron. According to the invention, the contents of Nb and C key alloy elements in the material are accurately controlled, so that Nb can be completely dissolved into a matrix in the smelting process, and the phenomenon of one-time NbC liquation is avoided. Heat treatment is directly carried out after smelting and casting, and the component control strategy is adopted, so that the precipitation of nano-sized dispersed NbC on an original austenite grain boundary is promoted, austenite grains are effectively pinned, and a microstructure with uniform and fine grain size is obtained; a martensitic structure is obtained through quenching, and uniform dispersion and precipitation of NbC carbide are realized in the martensitic structure through a subsequent tempering process, so that the strength and the toughness of the I-shaped front axle are ensured to reach the best match.

The invention relates to the technical field of magnetic materials, in particular to a grain boundary diffusion method of a neodymium-iron-boron rare earth permanent magnet material, which comprises the following steps: preparing a sintered neodymium-iron-boron diffusion matrix, a diffusion source being turbid liquid slurry consisting of a mixture of rare earth fluoride and rare earth oxide and a proper amount of organic solvent; the method comprises the following steps: processing a diffusion substrate into a required size, carrying out grain boundary diffusion treatment after oil removal and acid pickling treatment, coating the surface of the diffusion substrate with a diffusion source, drying the coated magnet, carrying out primary diffusion treatment, and carrying out secondary low-temperature tempering treatment. The diffusion method provided by the invention is simple in process, can effectively improve the coercive force of the neodymium-iron-boron magnet, especially the coercive force of a Ce-containing magnet, and is embodied in the following aspects: improving the anisotropic field of the surface of a crystal grain, improving the microstructure of a crystal boundary, effectively increasing the diffusion depth, obviously improving the coercive force of the magnet, and improving the coercive force of the neodymium-iron-boron magnet. And the original residual magnetism and the maximum magnetic energy product of the magnet are not obviously reduced.

The invention relates to the technical field of high-performance structural ceramic materials and corrosion resistance optimization thereof, in particular to a preparation method of high-performance silicon nitride ceramic, which realizes performance improvement through dynamic optimization of a composite sintering aid, closed-loop regulation and control of air pressure sintering and multi-process data linkage. In the raw material pretreatment stage, a laser particle size analyzer is adopted for monitoring particle size distribution in real time, surface modification parameters are adjusted in a linkage mode, and a uniform monomolecular coating layer is formed; the proportion of rare earth oxide and aluminum oxide in the composite sintering aid is dynamically adjusted according to the fluctuation of the mixing torque, and agglomeration and segregation of the aid are inhibited. And in the air pressure sintering stage, the argon pressure and the heating rate are dynamically adjusted based on the slope of a shrinkage curve, and directional arrangement of beta-phase grains is promoted by combining low-temperature nitrogen protection and high-temperature argon densification. And multi-dimensional process control synergistically optimizes grain boundary components, structure and density, so that the corrosion resistance and the service life of the silicon nitride ceramic in a sulfur-containing environment are remarkably improved and the service life of the silicon nitride ceramic in the sulfur-containing environment is remarkably prolonged.

Alloy elements are reasonably matched, N and nitrides are added to form elements such as tungsten W, vanadium V, niobium Nb, cobalt Co, rare earth RE and the like for microalloying smelting, a forged and rolled material finished product is subjected to proper heat treatment, and the stainless steel subjected to heat treatment has good heat treatment performance through metallographic observation. According to the stainless steel, nanoscale carbides are separated out in a solid solution state, and fine particles mainly containing nitrides are dispersed and separated out in crystals in a thermodynamic state, so that the material is strengthened and does not diffuse to a crystal boundary, and the room-temperature mechanical property and the high-temperature mechanical property of the material are greatly improved; and when the stainless steel material produced by the method is used for manufacturing related products, the thickness of the stainless steel material can be reduced, and the overall input of the stainless steel material is greatly reduced, so that the large-scale application of noble metal strategic resource nickel is saved, and the aims of saving resources, energy and investment are fulfilled.

The invention provides a deep learning-based bridge structure erosion degree monitoring method, which comprises the following steps of: for bridge steel samples of different types and parts, characterizing grain boundary structures and grain orientation microstructure characteristics by utilizing an electron back scattering diffraction method, and determining typical microstructure types of crystals; performing preprocessing and feature engineering processing on the obtained large sample data set, extracting chloride ion concentration and microstructure features, and constructing training data of an intercrystalline corrosion prediction model; according to the change rule of the chloride ion concentration and the typical microstructure type of the crystal, a bridge steel intergranular corrosion prediction model is constructed, and training and verification are carried out on a large sample data set; a wireless sensor network is arranged in a bridge steel service environment, chloride ion concentration and temperature and humidity environment parameters are collected in real time, and data needed by model input are obtained through data preprocessing and feature extraction.

The present invention discloses a medium-high performance neodymium iron boron and a preparation method thereof. Through the master-slave phase double alloy process, the master phase alloy is cerium iron boron with a low total rare earth content, and the slave phase is a neodymium iron boron alloy with a high total rare earth content, avoiding the entry of light rare earths in the master phase into the grain boundaries, while the surplus rare earths in the slave phase enter the grain boundaries and are recombined into rare earth-rich phases. The prepared magnet is processed into a thin magnetic sheet, and a low-melting-point HReM alloy is magnetron sputtered, realizing low-temperature grain boundary diffusion. This alloy improves the grain boundary wettability and also improves the fluidity of the rare earth-rich phase, enabling the cerium-containing neodymium iron boron master and slave phase grains to be quickly isolated during grain boundary diffusion. The low-temperature diffusion avoids the replacement of the diffused heavy rare earths by praseodymium, neodymium, and cerium elements, inhibits the exchange coupling between cerium iron boron grains, and makes the heavy rare earths free in the grain boundaries or interact with the rare earth-rich phase to form a core-shell structure on the surface layer of the master phase grains, enabling the rare earth-rich phase to be continuously and uniformly distributed, effectively enhancing the effectiveness of the grain boundary diffusion of heavy rare earth elements in improving the intrinsic coercivity of the cerium-containing magnet.

A method to achieve a yield ratio of 0.60 or more in a component from non-heat-treated steel having bainitic microstructure. The component includes a predetermined chemical composition, in mass %, in amounts such that a value of F1 obtained by Formula (1) is 0.65% or more, with the balance as Fe and inevitable impurity. Bainitic microstructure area fraction is 85% or more and Retained austenite area fraction is 5% or less. Crystal grains of the bainitic microstructure have an average diameter of 10 μm or more and 25 μm or less, an average aspect ratio of 0.5 or more, and an average ratio of crystal grain boundary length to crystal grain circumference of 60 or less.F⁢1=C+Si / 24+Mn / 6+Ni / 40+Cr / 5+Mo / 4+V / 14(1)

The invention discloses an yttrium-rich neodymium-iron-boron magnet and a preparation method thereof, and belongs to the technical field of rare earth permanent magnet material preparation. The preparation method comprises the following steps: mixing yttrium-rich neodymium-iron-boron matrix alloy powder with grain boundary doped alloy powder containing Gd and / or Ho, and carrying out compression molding and sintering tempering treatment to obtain a first yttrium-rich neodymium-iron-boron magnet. According to the invention, the grain boundary doped alloy powder containing Gd and / or Ho is added into the yttrium-rich neodymium iron boron matrix alloy powder and then is sintered, so that a continuous and uniform non-magnetic thin-wall grain boundary phase structure is formed in the grain boundary, and the coercive force of the magnet is enhanced. Dy and / or Tb heavy rare earth element grain boundary diffusion is carried out based on the first yttrium-rich neodymium-iron-boron magnet after grain boundary modification, a second yttrium-rich neodymium-iron-boron magnet is obtained, the diffusion depth of Dy and / or Tb in the magnet can be increased, the utilization rate can be increased, the cost can be reduced, the coercivity of the magnet can be improved, and the adverse effect of Dy and / or Tb on residual magnetism can be reduced.

The invention provides a perovskite thin film passivation modifier, a perovskite thin film and a preparation method thereof, and a perovskite solar cell. The passivation modifier comprises passivation molecules providing passivation groups; the passivation groups and uncoordinated lead ions or other defect sites in the perovskite thin film form coordinate bonds; the passivation group is amino. Amino groups in the passivation modifier have relatively strong coordination capability and can form coordination bonds with uncoordinated lead ions or other defect sites in the perovskite material, so that grain boundary and surface defects are passivated, and in addition, the three-dimensional structure of the passivation modifier is beneficial to preventing moisture and oxygen from invading the perovskite thin film; and the stability of the perovskite thin film is further improved.

The invention provides a high-strength and high-conductivity copper alloy with a fine grain structure and a preparation method of the high-strength and high-conductivity copper alloy, and belongs to the technical field of copper alloy preparation. The copper alloy comprises the following elements in percentage by mass: 2.0-12.0 wt.% of Ni, 0.4-3.0 wt.% of Si, less than or equal to 1.0 wt.% of Zn, less than or equal to 5.0 wt.% of Ti, less than or equal to 1.0 wt.% of B and the balance of Cu and inevitable impurities. According to the method, the heat treatment process is adjusted, generation of Ni16Ti6Si7 and TiB2 phases is promoted through introduction of Ti and B elements, micron-sized particles can serve as nucleation sites and pinning grain boundaries in the heat deformation process, and grain refinement is promoted. The high-strength and high-conductivity copper alloy with a fine grain structure is obtained by changing the content of Ti and B elements in the copper alloy and regulating and controlling the proportion of Ni16Ti6Si7, a TiB2 micron phase and a Ni2Si nano phase.

Disclosed are a neodymium-iron-boron magnet material, a preparation method, use thereof and a motor. The neodymium-iron-boron magnet material has an amorphous RE-rich phase located in a grain boundary phase. The amorphous RE-rich phase, containing elements TM, RE, Cu and Ga at an atom ratio of TM:RE:Cu:Ga=(15-30):(40-60):(10-25):(10-30), accounts for 3-8% by volume of the grain boundary phase. TM is Fe and Co. RE is a rare earth element. The neodymium-iron-boron magnet material increases the coercivity using none or a small amount of heavy rare earth elements, while maintaining high remanence and magnetic energy.

The invention relates to the technical field of neodymium-iron-boron magnets, in particular to a neodymium-iron-boron rare earth magnet and a preparation method thereof.The neodymium-iron-boron rare earth magnet is a sintered neodymium-iron-boron permanent magnet and comprises a main phase, a two-particle grain boundary phase and a triangular area grain boundary phase; the main phase comprises an R2T14B phase, R refers to at least one of Nd and Pr, T refers to Fe, and Co at least contains Fe; the two-particle grain boundary phase comprises a grain boundary copper-rich phase, and / or a needle-shaped ZrBx phase with the width of 10-50 nm, and / or a needle-shaped TiBx phase with the width of 10-50 nm; the triangular region grain boundary phase comprises an FCC type NdOx phase, an RCu phase, an RGa phase, an R-rich phase, a 6: 14 phase and / or a needle-shaped ZrBx phase with the width of 10-50 nm and / or a needle-shaped TiBx phase with the width of 10-50 nm, the neodymium-iron-boron rare earth magnet does not contain heavy rare earth and is good in uniformity, and the coercive force and residual magnetism can be regulated and controlled through the design of the grain boundary phase.

The invention relates to the technical field of piezoelectric materials, in particular to a lead zirconate titanate film and a low-temperature preparation method and application thereof.The preparation method comprises the steps that Ti metal serves as a radio frequency target material and is subjected to first sputtering deposition treatment on a substrate, and a Ti adhesion layer is formed; forming a bottom electrode on the Ti adhesion layer; taking PbxZr0. 52Ti0. 48O3 ceramic as a radio frequency target material, carrying out second sputtering deposition treatment on the bottom electrode, and carrying out rapid heat treatment to form a PZT seed layer; and carrying out third sputtering deposition treatment on the PZT seed layer by taking PbxZr0. 52Ti0. 48O3 ceramic as a radio frequency target material, carrying out rapid heat treatment, and repeating the step to form the lead zirconate titanate film. According to the method, the substrate tray is not additionally heated in the process of sputtering and depositing the PZT thin film material, so that the loss and volatilization of PbO are reduced, and the stability of thin film components can be effectively maintained; the PZT seed layer is utilized to provide more crystal nucleuses, so that the uniform crystallization of the PZT film is promoted, the crystallization quality and the electrical property of the PZT film are improved, the grain boundary defect is reduced, and the adhesive force and the stability of the film and the substrate are enhanced.

The invention provides a method for strengthening the coercive force of a neodymium-iron-boron magnet through composite reduction grain boundary diffusion, which comprises the following steps of: (1) mixing a reducing agent, a dispersing agent and a composite rare earth diffusion source to obtain mixed powder; the composite rare earth diffusion source comprises a multi-element rare earth compound diffusion source and / or a composite compound diffusion source; (2) coating the mixed powder obtained in the step (1) on the surface of a neodymium-iron-boron magnet to obtain a coating layer magnet; and (3) carrying out sectional composite reduction-grain boundary diffusion heat treatment and tempering treatment on the coated magnet in the step (2) to obtain the neodymium iron boron diffusion magnet. According to the method, the composite rare earth diffusion source is adopted, the preparation cost of the neodymium iron boron diffusion magnet is reduced, meanwhile, the grain boundary diffusion efficiency is improved, and the large-scale market application prospect is achieved.

The invention provides a method for preparing a high-coercivity sintered neodymium-iron-boron magnet, and belongs to the technical field of rare earth permanent magnet material preparation, and the method comprises the following steps: 1, taking the sintered neodymium-iron-boron magnet as a base material, and removing an oxide layer through alkali washing deoiling, ultrasonic water washing and acid pickling cleaning; 2, taking the Pr-Dy-Cu-Ga quaternary alloy as a diffusion source, and cutting the Pr-Dy-Cu-Ga quaternary alloy into slices; 3, attaching the thin sheet to the surface of a base material for diffusion heat treatment; fourthly, low-temperature tempering is conducted; 5, testing a room temperature demagnetization curve of the sample; light rare earth Pr replaces a part of heavy rare earth Dy and is matched with Cu and Ga elements in a certain proportion to be smelted to obtain quaternary alloy, the quaternary alloy with low heavy rare earth serves as a diffusion source, the microscopic characteristics of the magnet are improved, grain boundary phase distribution is optimized, and under the condition that residual magnetism and the maximum magnetic energy product are slightly reduced, the coercive force of the sintered neodymium-iron-boron magnet is improved; and terbium and dysprosium are not used, so that the use amount of heavy rare earth elements and the production cost are reduced.

The invention relates to the technical field of glass, in particular to microcrystalline glass and a preparation method thereof, reinforced microcrystalline glass and a preparation method thereof, and a glass product. The invention provides microcrystalline glass which comprises the following components in percentage by mass based on the total mass of 100%: 58.21-70.63% of SiO2; the content of Al2O3 is 6.46 to 7.83 percent; zrO2: 3.23% to 3.92%; 1.86%-2.3% of P2O5 (P2O5); 0.4 to 0.5 percent of B2O3; 1.9 to 14.4% of a rare earth metal oxide; an alkali metal oxide: 10.86 to 12.99%; wherein the rare earth metal oxide is prepared from Y2O3 and La2O3; the alkali metal oxide comprises Na2O and Li2O. According to the microcrystalline glass disclosed by the invention, the link of a glass network is enhanced by utilizing the rare earth metal oxide and Al2O3 together to form a high-density network structure, uniform nucleation is induced through the nucleating agent, fine grains are generated, grain boundary defects are reduced according to a multi-step nucleation-crystallization system, and the mechanical property is remarkably improved.

The invention discloses a grain boundary diffusion method of a high-performance sintered neodymium-iron-boron magnet. The preparation method comprises the following steps: sequentially carrying out hydrogen decrepitation, jet milling, magnetic field forming, cold isostatic pressing and low-temperature presintering treatment on a neodymium-iron-boron alloy rapid hardening sheet to obtain a presintered neodymium-iron-boron magnet; depositing a non-rare earth metal or metal oxide film layer on the surface of the pre-sintered magnet by using a pulse laser deposition process; performing diffusion heat treatment on the neodymium-iron-boron magnet deposited with the non-rare earth metal or metal oxide film layer; depositing a heavy rare earth element film layer on the surface of the treated neodymium-iron-boron magnet by using the pulse laser deposition process again; and performing diffusion heat treatment and tempering treatment on the treated neodymium-iron-boron magnet. According to the method, the diffusion cost is reduced, meanwhile, the diffusion depth of heavy rare earth elements in the magnet is increased, the neodymium-iron-boron magnet with high coercive force and high magnetic energy product is prepared, and the urgent application requirements of emerging industries such as rare earth permanent magnet motors are met.

The invention relates to a red copper material as well as a preparation method and application thereof. The red copper material comprises the following components in percentage by mass: 10-100ppm of at least one element of Zr, Ca and La, and the balance of Cu and inevitable impurities, the grain size of the red copper material is 10-25 microns, the volume percentage ratio L of small-angle grain boundaries and the volume percentage ratio H of large-angle grain boundaries are controlled to be larger than or equal to 2.0 and smaller than or equal to 2.4, the small-angle grain boundaries are grain boundaries with the adjacent grain orientation difference smaller than 15 degrees, and the large-angle grain boundaries are grain boundaries with the adjacent grain orientation difference larger than 15 degrees. According to the method, through specific annealing and cold machining modes and addition of grain refinement elements, high-temperature abnormal growth of grains is inhibited, and meanwhile the surface quality of the red copper material is optimized. The ceramic copper-clad material prepared by taking the obtained red copper material as a substrate can be applied to the fields of automobile connectors, semiconductor coolers, high-power power semiconductor modules and the like.

The invention relates to the field of additive manufacturing nano precipitated phase reinforced refractory high-entropy alloys, in particular to an additive manufacturing nano precipitated phase reinforced refractory TiNbVAlSix high-entropy alloy. The high-entropy alloy comprises the following chemical components by atomic percent: 45-55% of Ti; 15%-25% of Nb; v, 15%-25%; 8%-15% of Al; and 0-9% of Si. The alloy is prepared through a laser directional energy deposition additive manufacturing method, precipitation of a nano Ti5Si3 phase at the grain boundary and in grains is promoted through addition of the Si element, microstructure characteristics of a disordered BCC phase, an ordered B2 phase and the nano Ti5Si3 phase are formed, and the content of the nano Ti5Si3 phase is in direct proportion to the content of the Si element. The high-entropy alloy has the performance characteristics of light weight and high strength, can meet the requirements of part of aerospace parts, and has important value for development and application of TiNbVAl and related light refractory high-entropy alloy systems.

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 method for automatically evaluating the average grain size of a metal material by using a cross-point method, and relates to the field of metal material metallographic image analysis, and the method comprises the following steps: selecting an identification model according to a tested material; inputting the optical microscope image pic into a system with an identification model; extracting scale information of the input image pic by using mask extraction and Hough straight line detection: firstly extracting a scale region by using a mask, then extracting a scale length by using a Hough straight line detection algorithm, and finally extracting a scale value by using a KNN classifier; and identifying the grain boundary pixels of the input image by using the selected identification model: classifying each pixel of the input optical microscope image pic by using UNet, judging whether the pixel is the grain boundary pixel, finally performing optimization, performing intercept method rating according to the optimized grain boundary image, counting the number of intersections per unit length, and calculating the grain size G. According to the method, the precision and consistency of grain size evaluation are remarkably improved.

The invention discloses a neodymium iron boron magnet. The neodymium iron boron magnet comprises the following components: 28 to 33 weight percent of R, 0.85 to 0.94 weight percent of B, 0.05 to 0.6 weight percent of Co, 0.05 to 0.5 weight percent of Cu, 0.3 to 0.6 weight percent of Ga, 0.05 to 1.1 weight percent of M1, 0.1 to 0.5 weight percent of M2, 63.2 to 69 weight percent of Fe and the balance of Fe. Wherein R is a rare earth element, R at least comprises PrNd, and R comprises R1; r1 is selected from one or two of Gd and Ce; m1 is selected from at least one element of Al and Sn; m2 is selected from at least one element of Zr, Ti and Nb; the neodymium-iron-boron magnet comprises main-phase crystal grains, thin-layer crystal boundary phases and triangular-region crystal boundary phases, and distribution of the triangular-region crystal boundary phases meets the following conditions that the area of all triangular-region crystal boundary phases in the section of the neodymium-iron-boron magnet accounts for 6%-8.5% of the total area of the section; the triangular region grain boundary phase comprises an R6T13M1 phase, M is selected from one or more of Al, Cu, Ga, Ti, Sn, Zr and Nb, T is selected from one or two of Fe and Co, and the ratio R1 / R of the atomic percent of R1 to the atomic percent of R in the R6T13M1 phase is 6.0%-9.0%.

The invention discloses a high-performance sintered neodymium-iron-boron magnet and a preparation method thereof.The high-performance sintered neodymium-iron-boron magnet is characterized in that raw materials for preparing the neodymium-iron-boron magnet comprise a main alloy and an auxiliary alloy, and the auxiliary alloy does not contain Fe and Co elements; the microstructure of the neodymium-iron-boron magnet comprises a matrix phase and a rare earth-rich grain boundary phase, the matrix phase is (RE / RE ') 2 (F) 14B, F is Fe and Co, the content of Co is 0-3, the mass percent of Fe to RE / RE' in the rare earth-rich grain boundary phase is 1: (1.4-7), RE is Nd or PrNd, and RE 'is one or more of Pr, Ho, Dy and Tb. The neodymium-iron-boron magnet has relatively high magnet magnetic performance.