161 results about "Equiaxed crystals" patented technology

The invention provides a round billet continuous casting machine and multi-stage multi-mode electromagnetic stirring device matching method, and belongs to the technical field of metallurgy continuous casting, and the method comprises the steps that an electromagnetic stirrer in a crystallizer area applies a rotating magnetic field in the initial solidification stage, and the forming quality of an initial solidification shell is optimized; an electromagnetic stirrer in the secondary cooling area utilizes a traveling wave magnetic field to continuously regulate and control the solidification process of the core part of the casting blank; the feeding effect of a final solidification section is remarkably improved through the action of a high-intensity magnetic field by an electromagnetic stirrer in a solidification tail end area, and multiple matching modes are produced to be matched with existing continuous casting processes of different steel grades according to the characteristics of the steel grades, the throwing direction of each area and the type of the electromagnetic stirrer. And then through linkage of the multi-stage multi-mode electromagnetic stirring device and cooperative control over continuous casting process parameters, the equiaxed crystal area of the casting blank is enlarged, segregation is reduced, the internal quality of the casting blank is improved, and the density, uniformity and mechanical performance of the casting blank are improved.

The application provides a superplastic forming process for preparing a large-size titanium alloy component, and belongs to the field of welding, heat treatment and superplastic forming of metal materials. The process is characterized in that: two or more titanium alloy plates are spliced together by using a friction stir welding technology under low heat input, fine equiaxed crystal organization is obtained at the welding core, and then the large-size titanium alloy plate after splicing is subjected to heat treatment to further control the microstructure. By using the principle that the coarse rate of the fine organization is greater than that of the coarse organization during the heat treatment, the holding temperature and the holding time are adjusted, and finally the microstructure of the base material and the welding core is uniform. Then, under a specific process, the large-size titanium alloy plate with the weld is subjected to overall superplastic forming, synchronous superplastic deformation of the weld and the base material is realized, and a high-performance large-size titanium alloy integral component is prepared.

The invention belongs to the field of ferrous metallurgy, and particularly relates to a method for improving the quality of a continuous casting billet through ultrasonic waves. According to the method, a multi-directional focused ultrasonic field and solidification front edge dynamic regulation and control combined mode is adopted, and electromagnetic stirring phase difference control and cooperative control of a secondary cooling section (fan-shaped section) auxiliary ultrasonic vibrator are combined at the same time. Wherein the composite action mode of the longitudinal standing wave field and the transverse traveling wave field of the multidirectional focused ultrasonic wave field and the solidification front edge dynamic regulation and control mode act on the casting blank, so that the equiaxed crystal rate can be remarkably increased, and the combination of ultrasonic waves and electromagnetic stirring is beneficial to reducing the segregation degree of the casting blank; and the addition of nano aluminum oxide and magnesium oxide mixed particles in the casting powder is beneficial to improving sound wave conduction so as to reduce subcutaneous bubbles. The isometric crystal rate of the finally obtained continuous casting billet is increased to 30%-55%; the center segregation index of the finally obtained continuous casting billet is reduced to 1.05 or below; and the number of subcutaneous bubbles per square meter is less than 0.5.

The invention discloses a solidification melting zone thermal compensation repairing device and method for adjusting a heat source mode, and belongs to the technical field of metal part repairing. In the traditional Gaussian laser single crystal repairing process, columnar crystal orientation isometric crystal transformation can be induced due to the violent heat dissipation effect on the top of a molten pool and the component supercooling effect of the solidification front edge, new crystal grains preferentially nucleate and grow on the top of the molten pool, and the mixed crystal defect on the top of a repairing layer is caused. The scheme that annular laser is adopted as main laser, a thermal compensation auxiliary laser beam and a zoom laser beam expander are added for cooperative regulation and control is provided, the temperature gradient and the cooling speed of a molten pool are controlled by accurately adjusting a heat source energy distribution mode, the tendency of columnar crystal orientation isometric crystal transformation is restrained, and the quality of the molten pool is improved. And mixed crystal defects at the top of the repair layer are eliminated. Compared with an existing method, the method is large in process window and good in parameter adaptability; the material application range is wide, and the repairing requirements of different alloy systems can be met; equipment adjustment is simple, and industrial application is easy to achieve.

The invention belongs to the related technical field of additive manufacturing, and discloses an electron beam melting wire liquid nitrogen copious cooling additive manufacturing method and system.The method comprises the steps that in the electron beam melting printing forming process, liquid nitrogen is sprayed to a molten printing wire under electron beam irradiation, and the liquid nitrogen is sprayed to the molten printing wire; the molten printing wires are subjected to nitridation reaction under the action of electron beams while being subjected to liquid nitrogen cryogenic cooling, so that the crystal structure of a formed part is regulated and controlled, and the mechanical performance is enhanced; and / or liquid nitrogen is sprayed to the printing wire material which begins to be solidified, so that the printing wire material is subjected to liquid nitrogen deep cooling, and the crystal structure of the formed part is regulated and controlled to achieve mechanical property enhancement. Liquid nitrogen is introduced into the electron beam additive manufacturing device for deep cooling, the extruded printing wire is solidified at an extremely high cooling speed after being melted, a large number of homogeneous nucleation sites are formed in a melting area due to the high supercooling degree, the solidification speed is high, a microstructure is customized into uniform and fine equiaxed crystals, the strength and toughness of the material are improved, and the production cost is reduced. The mechanical property is improved.

The invention belongs to the technical field of alloys, and provides a lightweight refractory multi-principal-element alloy with excellent high-temperature creep property, and a preparation method and application thereof. The general formula of the light refractory multi-principal-element alloy with the excellent high-temperature creep property is TiaVbAlcCrdMoe, wherein 43% < = a < = 48%, 43% < = b < = 48%, 2% < = c < = 8%, 2% < = d < = 8% and 1% < = e < = 5%, a + b + c + d + e = 100%, and a, b, c, d and e are mole percentages. The alloy presents an isometric crystal structure in a complete recrystallization state in a thermal mechanical treatment state, the phase structure is a single-phase body-centered cubic BCC structure, the alloy has low density and shows excellent creep property at 650 DEG C / 100 MPa, the creep time exceeds 90 h, and the creep elongation is lower than 10%.

The invention discloses a method for preparing fine-grain copper and copper alloy through pulsed magnetic field and rare earth adding composite regulation and control, and belongs to the technical field of copper and copper alloy material preparation. Graphite mold casting is adopted in the method, and the method comprises the specific steps that electrolytic copper with the purity larger than or equal to 99.95 wt% or a copper alloy with specific components is prepared as a matrix raw material; after smelting, adding pure lanthanum blocks and uniformly stirring; after the melt is poured into a preheating mold, a pulsed magnetic field is applied immediately for treatment, and the parameters of the magnetic field are as follows: the pulse voltage is 180-250 V, the frequency is 4.5-6.5 Hz, and the duration time is 15-20 minutes. According to the method, the heterogeneous nucleation effect of rare earth lanthanum is combined with the melt forced convection and dendritic crystal crushing effect caused by the pulsed magnetic field to synergistically refine a solidification structure and promote columnar crystal orientation equiaxed crystal transformation, so that a cast ingot with fine crystal grains is directly obtained in the casting stage, and the possibility is provided for simplifying the subsequent processing technology.

The invention relates to the technical field of heat treatment of steel for high-performance heading machine tools, and discloses an ultra-fine grain solid-phase regulation and control process for improving the structure uniformity of alloy steel, which comprises the following steps: collecting electrical parameters of an induction loop and identifying sudden change of parameters of a phase change point to determine a phase change leading edge position; triggering pulse disturbance heating at a preset depth to generate transient volume dislocation stress, breaking core carbide segregation and driving stress extreme values to gather towards the center; controlling the temperature rise rate to make the nucleation rate higher than the diffusion rate so as to form a dispersed crystal nucleus; according to the method, the phase change transient volume dislocation strain field is used for blocking the continuity of the net-shaped hard and brittle phase, the structure heredity of the large-scale section steel is eliminated, the total cross-section structure is highly homogenized, equiaxed crystals are ultra-refined, and the intergranular fracture resistance of the material in the service environment is enhanced.

The invention discloses a continuous casting production method of a medium carbon steel large round billet, which is characterized in that electromagnetic stirring is carried out in the following three solidification stages in the continuous casting process of the large round billet: (1) electromagnetic stirring is carried out at the middle lower part of a crystallizer, and the value range of magnetic field intensity distribution along the center line of the crystallizer is 0-10mT; (2) electromagnetic stirring is conducted at the position where the solidification rate of the casting blank ranges from 65% to 75%, and the value range of magnetic field intensity distribution ranges from 7 mT to 16 mT; and (3) electromagnetic stirring is conducted at the position where the solidification rate of the casting blank is 85%-90%, and the value range of magnetic field intensity distribution is 10-25 mT. The method acts on the casting blank in the appropriate solidification process, appropriate electromagnetic stirring force is applied, and macrosegregation of the large round blank is improved; the electromagnetic field is used for acting on three casting blanks in different solidification stages, on one hand, the flow field in the crystallizer can be improved, and the impact depth is reduced; and on the other hand, electromagnetic stirring is used in a casting flow area to reduce positive segregation of a CET area, the grain size of an equiaxed crystal area is refined, then the macrosegregation degree of a casting blank is reduced, and the carbon range is reduced.

The application belongs to the technical field of aluminum alloy additive manufacturing, and particularly relates to an in-situ strengthening method for improving the fracture toughness of aluminum alloy in additive manufacturing, which comprises the following steps: (1) preparation before additive manufacturing; drying high-strength aluminum alloy powder and then putting the powder into a powder feeder; (2) setting of a remelting width of a forming path; the remelting width is controlled by a laser scanning interval method or a line energy density method; and (3) additive manufacturing and heat treatment; through the setting of the remelting width, partial grain remelting and re-nucleation and growth are realized, at the bottom of a molten pool, new crystal nuclei form fine equiaxed crystals with Al3(Zr, Er) as the core instead of epitaxial columnar crystals; through the alternate distribution of the columnar crystals and the equiaxed crystals, the crack propagation resistance is increased, and the fracture toughness of the material is significantly improved, while the high-strength characteristics are maintained.

The application provides a method for rapidly improving the surface structure and roughness of a cast aluminum alloy part, and relates to the technical field of laser beam processing, and comprises the following steps: fixing the cast aluminum alloy part on a multi-axis movable object platform; using a continuous laser beam to scan the initial surface layer of the cast aluminum alloy part, and controlling the laser power and scanning speed to make adjacent molten pools continuously overlap to form a uniform molten layer; when the thickness of the uniform molten layer reaches a first preset thickness required for surface structure reconstruction, stopping the laser scanning; the uniform molten layer is self-cooled and solidified in a room temperature environment to form a solidified surface layer; wherein the solidified surface layer forms a submicron equiaxed crystal structure, and the roughness of the solidified surface layer is smaller than that of the initial surface layer. The method directly generates a submicron equiaxed crystal structure under the condition of room temperature self-solidification by accurately controlling the molten pool overlap and the cooling rate, and achieves the purpose of rapidly modifying the surface layer of the cast aluminum alloy part.

The application discloses an alloy vacuum self-consumption electric arc smelting magnetic pulse grain refining device, which comprises a vacuum self-consumption electric arc furnace body and a copper crucible, a metal molten pool is arranged in the copper crucible, a plurality of non-contact magnetic pulse coils are wound on the outer wall of the copper crucibble, and a water-cooling interlayer is arranged between the vacuum self-consumption electric arc furnace body and the copper crucible; a screw rod is arranged between the vacuum self-consumption electric arc furnace body and the copper crucible, and the screw rod is connected with a motor. The application further discloses a method for alloy vacuum self-consumption electric arc smelting magnetic pulse grain refining, cooling water is introduced into the water-cooling interlayer, a power supply of the vacuum self-consumption electric arc furnace is turned on for smelting, a pulse power supply is turned on when the height of the metal molten pool formed at the bottom of the copper crucible reaches 50 mm, and the plurality of non-contact magnetic pulse coils are uniformly moved upwards until the process is finished. The metal molten pool is directionally treated by electromagnetic pulse in a moving mode, the columnar crystal-equiaxed crystal transition is realized in the alloy ingot preparation process, the grain is refined, and segregation is reduced, so that the overall organization of the large-size long ingot is refined.

The invention relates to a method and a device for regulating and controlling the structure performance of a nickel-based high-temperature alloy in pulse laser-assisted additive manufacturing, and belongs to the technical field of additive manufacturing. The method comprises the following steps: controlling the oxygen content in a sealed forming cabin of an LPBF forming device, and paving nickel-based high-temperature alloy powder on a substrate of the sealed forming cabin; and the pulse laser and the continuous laser are controlled to output laser beams, the pulse laser beams and the continuous laser beams are coupled in a polarization beam combination or wavelength beam combination mode, and after the focal length of the coupled laser beams is adjusted, the nickel-based superalloy powder on the substrate is subjected to fusion forming. According to the method, the pulse laser and the continuous laser are coupled into the coaxial light spots, in-situ synchronous disturbance on the molten pool in the LPBF additive manufacturing process is achieved, the solidification behavior of the nickel-based high-temperature alloy can be accurately regulated and controlled, epitaxial growth of columnar crystals is effectively broken, formation of fine isometric crystals is promoted, and the yield of the nickel-based high-temperature alloy is improved. And the anisotropy and cracking risk of the material can be reduced.

The invention belongs to the technical field of aluminum alloys, and particularly relates to a high-strength and high-toughness microalloyed Al-Cu-Mg alloy with good creep property as well as a preparation method and application of the high-strength and high-toughness microalloyed Al-Cu-Mg alloy. The preparation method of the microalloyed Al-Cu-Mg alloy comprises the following steps that raw materials are weighed and fully mixed; performing vacuum drying after mixing; a micro-alloyed Al-Cu-Mg alloy is prepared by adopting a selective laser melting technology; the raw materials comprise, by mass, 96% of Al-Cu-M alloy powder, 1%-2% of Si powder and 1%-2% of Zr powder. Based on Si-Zr composite microalloying, the alloy which is free of obvious hot cracks and high in compactness is prepared through the selective laser melting technology at the high scanning speed, and the double-peak grain structure of the alloy is promoted to be further refined or transformed into a fine equiaxed crystal structure, so that the strength plasticity and creep property of the aluminum alloy are obviously improved.

The application relates to the technical field of refractory metal material processing, in particular to a vacuum smelting system and method for high-purity molybdenum and a fiber-structure molybdenum material, the vacuum smelting system for high-purity molybdenum comprises a three-layer composite crucible, the vacuum smelting method for high-purity molybdenum comprises the following steps: step S1): under the condition of a vacuum degree of less than or equal to 5*10 ‑3 Pa, a three-layer composite crucible is used to perform consumable smelting on molybdenum raw materials; step S2): a directional solidification rate is controlled to be 8-12 mm / min, and a longitudinal temperature gradient is formed to be greater than or equal to 100 DEG C / cm; step S3): multi-stage plastic deformation is implemented on a solidified ingot, and a total deformation amount is greater than or equal to 90%; the fiber-structure molybdenum material is formed with a longitudinal continuous fiber structure in the material, a grain length-diameter ratio is greater than or equal to 10:1, a fiber diameter is less than or equal to 5 microns, hydrogen content is less than or equal to 5 ppm, oxygen content is less than or equal to 50 ppm, and a room-temperature tensile strength is greater than or equal to 780 MPa; the application can prepare high-purity fiber-structure molybdenum material, and improves the problem of insufficient axial performance caused by the isotropy of a traditional equiaxed crystal structure.

This invention discloses a method for controlling the uniformity of gear steel microstructure, including hot metal desulfurization and vanadium extraction, semi-steel converter smelting, LF refining, RH refining, and continuous casting processes. The method controls the solidification process of the molten steel in the molten pool during continuous casting, ensuring solidification is completed within a 1 / 4 arc-shaped region of the slab, and implementing a specified cooling and solidification control process. This method effectively improves the macroscopic solute concentration uniformity in all directions of the cross-section of the gear steel continuous casting slab, improves the regional symmetry of the solidified microstructure, and promotes more uniform phase transformation and stress distribution in the gear microstructure during gear processing and subsequent heat treatment. The range of distance between the equiaxed crystal zone boundary and the slab surface is reduced from 30-40 mm to 10-15 mm. After rolling into a round bar, the range of distance between the equiaxed crystal trace zone boundary and the round bar surface is controlled to ≤5 mm, and the range of solute segregation (circumferential) at the same radial distance from the surface of the round bar is ≤0.02. The resulting gear steel grain size stabilizes from grade 6.0-7.0 to grade 7.0.

A preparation method for a gradient near-equiaxed crystal Cr coating on the surface of a zirconium alloy cladding is described. According to the present invention, a high-power impulse magnetron sputtering technology is adopted, and by self-modification of HiPIMS equipment, argon gas is introduced into a zirconium alloy cladding tube, the flow rate of the argon gas in the tube is controlled to regulate and control the tube wall temperature, parameters such as bias voltage, target-substrate distance, sputtering pressure and the like are comprehensively controlled to obtain a pure Cr near-equiaxed crystal coating on the surface of the zirconium alloy with three-layer gradient structure grains. The coating has good toughness and can improve the high-temperature oxidation resistance of the zirconium alloy cladding, significantly enhancing the ability of the cladding to resist serious accidents of the reactor.

The application belongs to the field of aluminum-based composite materials, and particularly relates to a kind of additive manufacturing high-performance aluminum-titanium metal composite material and a preparation method thereof. Micron-sized aluminum alloy powder and micron-sized titanium alloy powder are mixed uniformly by ultrasonic-assisted water bath stirring method for laser powder bed melting, wherein the mass fraction of the aluminum alloy powder and the titanium alloy powder is 85-98 wt.% and 2-15 wt.% respectively. The micron-sized titanium alloy powder is used to promote the formation of multi-scale layered structure of equiaxed crystal, core-shell structure, cellular substructure and nano precipitate phase, so as to simultaneously improve the strength and plasticity of the material and realize isotropic mechanical properties. The aluminum alloy-titanium metal composite material for additive manufacturing disclosed by the application has simple and easy-to-control process and low cost, and can be suitable for large-scale production.

The present application relates to the technical field of steel rolling, and particularly relates to a method for predicting the size of a center equiaxed crystal zone of an ingot in a rolling process, which comprises the following steps: S1, obtaining the height and width of an original ingot cross section and the height and width of a center equiaxed crystal zone; S2, according to a rolling method, determining the height and width of the ingot cross section after n-pass rolling based on the height and width of the original ingot cross section by using a Usatov spread formula; S3, based on the height and width of the original ingot, the height and width of the center equiaxed crystal zone, and the height and width of the ingot after n-pass rolling, calculating the height and width of the center equiaxed crystal zone of the ingot after n-pass rolling by using formulas (1) and (2); and S4, based on the height and width of the center equiaxed crystal zone of the ingot after n-pass rolling, calculating the box ratio of the center equiaxed crystal zone of the ingot after n-pass rolling. The method provided by the present application is simple to calculate and fast to respond.

This invention discloses an anti-scaling and anti-wax alloy material for circulating water systems and its surface treatment method, relating to the field of scale inhibition and prevention. The material includes an alloy matrix, the chemical composition of which, by mass percentage, is as follows: Cu 60-75%, Zn 15-28%, Al 3-8%, Ni 1.2-3.5%, Sn 0.5-2.0%, rare earth composite agent 0.1-0.8%, B 0.02-0.15%, with the balance being unavoidable metallurgical impurities. The metallographic structure of the alloy matrix is ​​ultrafine equiaxed crystals with an average grain size ≤5μm and a material density ≥99.5%. This invention utilizes a Cu-Zn-Al-Ni-Sn alloy system with a specific ratio of rare earth composite agent and trace amounts of boron, supplemented by ultrafine equiaxed crystal structure control, and then undergoes a composite surface treatment involving plasma nitriding, micro-arc oxidation, and vacuum impregnation with fluorosilane. The resulting anti-scaling and anti-wax alloy material for circulating water systems possesses both stable mechanical and electrical properties and excellent adaptability to the water environment.

The invention relates to the technical field of titanium alloys, in particular to a preparation method of a microtexture heterostructure titanium alloy and the microtexture heterostructure titanium alloy. The preparation method of the microtexture heterostructure titanium alloy comprises the following steps that titanium alloy powder obtained after hydrotreating and hydrogenated and dehydrogenated titanium powder are mixed and pressed into a blank, sintering and hot extrusion are conducted, and alpha-Ti in the obtained titanium alloy forms lt in the direction parallel to the hot extrusion direction; 0001 gt, 0001 gt; and meanwhile, the material has a heterostructure of an isometric crystal and an alpha-Ti / beta-Ti lamellar structure. Titanium alloy powder subjected to hydrotreating and hydrogenated and dehydrogenated titanium powder are mixed, so that the strength of a pressed blank is improved, the oxygen content is reduced, the sintering temperature is reduced, meanwhile, different recrystallization degrees occur in the sintering and thermal deformation process, different grain sizes, crystal orientations and phase distributions are presented, and the lt is actively constructed; 0001 gt, 0001 gt; the microtexture heterostructure titanium alloy material achieves comprehensive improvement of strength, plasticity, fracture toughness and other properties.

The application discloses a manufacturing method of an ultra-low-temperature high-strength non-magnetic austenitic stainless steel rod, which comprises the following steps: forming a fine-grain protective layer on the surface of a steel ingot by radial forging, small-deformation high-frequency forging and breaking down, so as to reduce the cracking risk in the fast forging process; increasing the forging ratio by fast forging, upsetting and elongating; and making the structure of the center of the steel ingot recrystallize to a certain extent; and finally, forming the steel rod by radial forging, large-deformation low-frequency forging and breaking down, so that dynamic recrystallization occurs in the whole cross-section of the steel rod, and uniform equiaxed crystals are formed, thereby solving the problems of multiple forging times, easy surface cracking and poor structure uniformity of the ultra-low-temperature high-strength non-magnetic austenitic stainless steel rod.

The present application belongs to the technical field of nickel-based alloy seamless pipe and its manufacturing technology, and particularly relates to a coarse equiaxed crystal structure N08120 nickel-based alloy seamless pipe and a preparation method thereof. By controlling the content of carbon, chromium, nickel and niobium and the like in the N08120 nickel-based alloy, and the cold rolling deformation and the heat treatment temperature, the formation and uniform distribution of the coarse equiaxed crystal structure in the nickel-based alloy seamless pipe are ensured, and the performance of the N08120 nickel-based alloy seamless pipe is not adversely affected. The preparation method of the N08120 nickel-based alloy seamless pipe provided by the present application realizes the requirement of the nickel-based alloy seamless pipe having the coarse equiaxed crystal structure, and the prepared seamless pipe has good high-temperature stability, corrosion resistance and mechanical properties, high size precision and good surface quality, and can be used in the structural material field of various specifications of furnace pipes, heating pipes and hot storage devices and the like, improves the stability and corrosion resistance of the structural material, and has important significance for actual production.

The present application relates to a method for controlling the solidification segregation of niobium in ferritic stainless steel containing niobium, and the smelting of the ferritic stainless steel comprises the following process flow: primary smelting, VOD furnace refining, LF furnace refining, continuous casting and casting, and the method comprises the following steps: after the molten steel is well reduced after primary smelting, the prepared niobium metal is added to the molten steel at one time, and the stirring intensity of bottom blowing is greater than 600 NL / min, and the stirring time is more than 10 min; and the parameters of the continuous casting process are controlled to improve the equiaxed crystal ratio of the casting blank. The present application controls the solidification segregation of niobium in ferritic stainless steel containing niobium from the aspects of molten steel niobium alloying process and continuous casting process, reduces the intergranular segregation of niobium in the primary blank shell of continuous casting, improves the equiaxed crystal ratio of the casting blank, and further improves the banded structure defects of the rolled material caused by the solidification segregation of niobium.

A method for manufacturing an equiaxed crystal target material, comprising the following steps: a metal bar is made into a forged base material by a radial forging process; the forged base material is made into a first plate material by a rolling process and a plate forging process, the rolling process is rolling along the axial direction of the forged base material; a second plate material is obtained by reciprocating an equal channel angular extrusion process on the first plate material with an equal channel angular extrusion die, the cumulative average equivalent strain of the second plate material is greater than 10, wherein the feeding direction of the first plate material into each equal channel angular extrusion die is the same as the rolling direction of the forged base material; and an annealing and recrystallization heat treatment process is performed on the second plate material to obtain an equiaxed crystal target material. Through the above steps, an equiaxed crystal target material with a grain size of not greater than 20 μm can be obtained for use in the semiconductor industry.

The invention provides a high-strength and high-toughness titanium-aluminum coating and a preparation method and application thereof.The preparation method comprises the following steps that A, first mixed powder and second mixed powder are laid on the surface of a titanium alloy component layer by layer, and a prefabricated titanium-aluminum coating is obtained; the first mixed powder comprises Ti powder and TC4 powder; the second mixed powder comprises Al powder and TC4 powder; and (B) pulse current treatment is conducted on the prefabricated titanium-aluminum coating, and the high-strength and high-toughness titanium-aluminum coating is obtained. According to the method, gradient thermal expansion coefficient matching and interface stress reduction are achieved by arranging the multiple TC4 alloy transition layers, pulse instantaneous energy of pulse current treatment can enable local micro-areas of the coating to be remelted, grain growth is restrained, submicron-order equiaxed crystals are obtained, dislocation slippage is induced by electromagnetic force, residual stress is released, and the thermal expansion coefficient of the coating is reduced. And in addition, the in-situ exothermic reaction promotes mutual diffusion of elements, a metallurgical bonding interface is formed, and the strength and toughness of the coating are improved.

The present application relates to an electrolytic copper foil and a preparation method therefor, a negative electrode sheet, and a secondary battery. The electrolytic copper foil comprises at least one copper layer, the ratio coefficient of columnar crystals to equiaxed crystals in a cross-section of the copper layer along the thickness direction being TJM, the maximum average value of grain boundary angles being KAMmax, and the grain size being R; the cross-section satisfies at least one of the following conditions (1)-(3): (1) 0.2≤TJM≤0.4; (2) KAMmax≤5.5°; and (3) the proportion of grains for which R≤0.3 μm is 40% -50%, the proportion of grains for which R≤0.4 μm is 70% -80%, and the proportion of grains for which R≤0.5 μm is greater than or equal to 95%. The described electrolytic copper foil has high tensile strength, high elongation, and high thermal stability.

1. Name of the product in this design: Casting Chamber Assembly. 2. Application of this design: for use in the mold chamber assembly of an equiaxed crystal vacuum precision casting furnace. 3. The key design feature of this product is its shape. 4. The image or photograph that best illustrates the design's key points: a 3D model.

This invention discloses a flaw detection method to improve the accuracy of shrinkage cavity detection in titanium alloy ingots. Specifically, instead of drilling ejector pin holes, flaw detection is performed directly within a 200mm radius of the center of the ingot head end face. After sawing the riser, an ultrasonic coupling agent is applied within a 200mm radius of the center of the sawn surface of the riser, and then the end face flaw detection is repeated. This flaw detection method avoids the interference of longitudinal columnar crystal and equiaxed crystal interface or ejector pin holes on the flaw detection signal in traditional titanium alloy ingot flaw detection methods, improves the accuracy of ultrasonic detection of shrinkage cavities in titanium alloy ingots, and avoids the problem of misinterpreting longitudinal columnar crystal and equiaxed crystal interface signals or ejector pin hole signals as shrinkage cavity signals, thereby increasing the sawing amount at the ingot head end.

This invention provides a high-strength, high-ductility 7075 aluminum alloy and its preparation method, belonging to the field of additive manufacturing. The alloy composition, by mass percentage, is: Zn: 7.5-8.5%, Mg: 2.7-3.7%, Zr: 1.0-3.0%, Cu: 1.5-2.5%, Ti: 0.7-1.3%, Y: 0.1-0.4%, with the balance being Al and unavoidable impurities, the impurities being ≤0.02%. The alloy preparation method includes: forming under high-purity argon protection using laser powder bed melting process, solution treatment, and aging treatment. The alloy has an average grain size ≤2.1μm and a three-peak structure, consisting of columnar crystals (5%-25% area), coarse equiaxed crystals (30%-60% area), and fine equiaxed crystals (35%-55% area). The 7075 aluminum alloy possesses high-density nanoscale η-Mg(Al,Zn,Cu)2 phase (radius ≤ 19 nm), primary L12-Al3Zr phase (radius ≤ 50 nm), and secondary L12-Al3Zr phase (radius ≤ 2.9 nm). The alloy exhibits a tensile strength ≥ 515.9 MPa and an elongation ≥ 12.7%, achieving a synergistic improvement in both strength and ductility.