69results about How to "Fine and uniform grain size" patented technology

A RE oxide doped fine-crystal Mo-alloy is prepared from MoO2 through doping RE oxide by atomizing method, ball grinding, sieving, reducing in H2 atmosphere in muffle furnace at 800-1100 deg.C, cold isostatic pressing under 150-200 MPa for shaping, segmental sintering in MF induction furnace and mechanical deforming to obtain rod or plate. It has high strength, ductility and toughness.

The invention relates to a preparation method of a molybdenum alloy electrode material doped with nano rare oxides. According to the preparation method, molybdenum powder is used as a raw material, the molybdenum powder and nano rare oxide powder are uniformly mixed by adopting a solid-solid doping method, wherein the nano rare oxides are lanthana oxide, cerium oxide or mixed rare earth oxide; and then the molybdenum alloy electrode material doped with different kinds and contents of nano rare earth oxides is prepared through adopting the processes of sieving, pressing and forming, sintering,forging and vacuum annealing heat treatment under certain temperature. The preparation method disclosed by the invention and the heat treatment process are simple and feasible; and the molybdenum alloy electrode material doped with the nano rare earth oxides, which is prepared by using the method disclosed by the invention, has the characteristics of uniform tissues, high compactness, high strength, high recrystallization temperature, high elongation rate, favorable deep processing performance, and the like.

The invention discloses a process method for obtaining a bimodal grain size distribution ultra-fine grain structure of hypoeutectoid steel. The method obtains an ultra-fine grain structure through a control process method. The ultra-fine grain structure is characterized by: The distribution of medium grain size has bimodal characteristics, that is, there are relatively large grains with a fractional size of 1-3 μm in the ultra-fine grain matrix with a diameter of 0.4 μm or less; the composition characteristics of this type of engineering steel are containing Hypoeutectoid steel with carbon mass fraction less than 0.4%. The invention can be combined with the controlled warm rolling technology to economically produce ultra-fine grain steel plates and strips with high ductility.

The invention discloses a technology of processing a magnesium alloy with high intensity and flexibility, which subsequently includes vacuum melting, continuous casting, extrusion, forging and such procedures. The invention reasonably matches the solution body composition and the metamorphism liquid during casting process, and the grains are refined through the chilling action of a crystallizer at first; the magnesium alloy liquid is transmitted by an electromagnetic pump so as to prevent secondary oxidation and ensure safety in casting of the magnesium alloy; and then further refining the grains through electromagnetic mixing power, large ratio extrusion and heat treatment secondary crystallization, which effectively ensures tiny enough isometric crystals can be obtained from the alloy microstructure. The magnesium alloy elements of the automotive steering control arms, support elements of motorcycles and bicycles, can be obtained for the first time by the improvement, which are fully filled, good in surface quality, fine and even in grain size, reasonable in streamline distribution and without disordered streamline, vortexing and draining phenomena. The invention combines a plurality of technological processes into a production cycle, which reduces the turnover links, saves energy and reduces cost.

A process for preparing high-purity Ti-Al-C block by discharge plasma sintering includes such steps as proportionally mixing Ti3AlC2 powder or Ti powder, Al4C3 powder and active carbon powder, ball grinding, baking sieving, loading in graphite mould, discharging plasma sinter under protection of inertial gas, holding the temp for a certain time and cooling. Its advantages are high purity (90% or more) and high mechanical performance.

The invention provides a preparation method of a high performance nanometer lanthanide oxide doped molybdenum-silicon-boron alloy. The preparation method comprises the following steps: molybdenum powder, silicon powder and boron powder are used as raw materials, different contents of nanometer lanthanide oxide are doped, the materials are mixed evenly through ball milling, prepressing and presintering are performed, the obtained sintered body is smelted in a vacuum arc furnace, the smelting working current is 800-1000A, the obtained alloy ingots are ground and subjected to ball milling to prepare powder, the alloy powder is sieved with a 200-300 mesh Tyler sieve, the obtained alloy powder is sintered in a vacuum hot-pressing sintering furnace at 1500-1700 DEG C and 30-50MPa for 1-3 hours,and the product is cooled to the room temperature along with the furnace after sintering. By adopting the method, the defects such as high sintering temperature, long time, inadequate reaction and more macro-defects, of the traditional powder metallurgy technology for preparing the molybdenum-silicon-boron alloy can be overcome; and the prepared nanometer lanthanide oxide doped molybdenum-silicon-boron alloy is characterized by uniform structure, high density and high strength.

The invention belongs to the field of chemical power electrode materials, and discloses an anode strip material for a magnesium-air battery and a preparation method and application thereof. The preparation method comprises the steps of: placing magnesium, aluminum, lead and a magnesium-rare earth intermediate alloy into a graphite crucible, filling with argon gas, and casting a stirred melt into astainless steel crucible in a furnace to obtain a cerium and yttrium-modified casting state AP65 magnesium alloy; under an argon protection atmosphere, homogenizing and annealing the magnesium alloyand quenching with water; after preheating, performing hot extrusion, and controlling the amount of extrusion deformation to obtain a series of magnesium alloy strips with different thicknesses. The microstructure of the AP65 magnesium alloy can be regulated by alloying and extrusion deformation, so that the AP65 magnesium alloy has good corrosion resistance under an open circuit potential, can discharge, uniformly dissolve and inhibit hydrogen evolution under certain current density, thereby having a high open circuit voltage, discharge voltage and high anode utilization rate, and is suitableas anode materials for magnesium-air batteries.

The invention belongs to the technical field of metal materials, and particularly relates to a preparation method of a high-strength and high-toughness CrCoNi medium-entropy alloy homogeneous fine-grain thin plate. The preparation method comprises the five steps of vacuum smelting, alloy ingot annealing, hammer cogging and drawing-out and high-temperature back-and-forth rolling forming. Accordingto hammer cogging and drawing-out, upsetting and drawing-out forging treatment is carried out on an annealed alloy cast ingot to prepare a plate blank; and the upsetting rate is 50-200 mm/s, and the drawing-out forging ratio is 2-10. According to the method, hammer cogging and drawing-out treatment is carried out after annealing, a large number of dendrites in an as-cast structure can be completely broken through severe plastic deformation in a short time, a fine and uniform grain structure is obtained, and metallurgical defects such as pores and looseness are reduced; and a high-temperature back-and-forth rolling process method is adopted, the grain size and the structure are refined, the strength, plasticity and toughness of materials are improved, and the anisotropy problem of an CrCoNimedium-entropy alloy is obviously reduced.

The invention relates to a nanocrystal ceramic corundum abrasive material and a preparation method thereof, and belongs to the field of ceramic corundum abrasive materials. The nanocrystal ceramic corundum abrasive material is prepared from the following components of Al2(SO3)3.18H2O and additives, wherein the additives comprise a dispersant, a liquid composite sintering additive and an Al2O3 (aluminum oxide) sol crystal seed. The preparation method of the nanocrystal ceramic corundum abrasive material comprises the following steps of adding the liquid composite sintering additive and the Al2O3 sol crystal seed into an Al2(OH)3 gel precursor; performing uniform ball milling, and drying by stages, so as to obtain a dry gel; crushing the dry gel, granulating, and screening, so as to obtain gel particles meeting the particle size requirement; calcining the gel particles by sections, cooling along with a furnace, and screening, so as to obtain the ceramic corundum abrasive material with different particle sizes. The invention also discloses a preparation method of the Al2O3 sol seed crystal and the prepared ceramic corundum abrasive material. The nanocrystal nanocrystal ceramic corundum abrasive material has the advantages that by introducing the Al2O3 sol crystal seed, the defects of difficulty in introducing of solid-state nanocrystal seeds and nonuniform mixing are overcome, andthe uniform mixing of the raw materials and additives is guaranteed; the microtopography with fine and uniform crystal seed size is realized, and the compressive strength and grinding property are improved.

The invention discloses a heat-treatment-free high-toughness die-casting aluminum alloy and a preparation method thereof. The alloy comprises the following components in percentage by weight: 7.5 to 9.5 percent of Si, 0 to 1.5 percent of Ni, 0.4 to 0.8 percent of Mn, 0 to 0.4 percent of Mg, 0.08 to 0.3 percent of Cr, 0.01 to 0.15 percent of Zr, 0.03 to 0.1 percent of Ti, 0.005 to 0.025 percent of Sr and the balance of aluminum and inevitable impurity elements. The die-casting aluminum alloy is good in thermal stability, the mechanical property change does not exceed 10% after the die-casting aluminum alloy is kept at the temperature not higher than 150 DEG C for 1000 h, the die-casting state yield strength is larger than 120 MPa, the elongation is larger than 14%, the performance requirement of a car body die-casting structural part can be met without subsequent heat treatment, and the die-casting aluminum alloy is suitable for large-scale production. And the percent of pass of thin-wall die-casting structural part products can be greatly increased, and the use cost of automobile parts is reduced.

The invention discloses a sol-gel preparation method of barium titanate PTC ceramics, which comprises the following steps that: (1) the materials are measured according to the formula (Ba1-xYx)TiO3, and x is equal to 6 to 20 permillage, barium acetate water solution with the concentration of 1.3 to 1.6 mol/L is prepared, and tetrabutyl titanate solution with the concentration of 1.0 to 1.3 mol/L is prepared; (2) Y(NO3)3.6H2O is incorporated into the Ba(CH3COO)2 water solution, and then the mixed solution is dropped into the Ti(OC4H9)4 solution to obtain the mixed solution; (3) the mixed solution is held at the room temperature to obtain the sol, and the sol is dried to obtain the gel; (4) the gel is smashed, ground and sieved to be pre-burned to synthesize the BaTiO3 powder containing yttrium; (5) the BaTiO3 powder containing the yttrium, the BaCO3 and the BN are measured according to the mol ratio of 1: (0.02 to 0.03) : (0.04 to 0.06) and are mixed and ball milled after being added with deionized water; (6) the BaTiO3 powder containing glass-phase raw material is ball milled with solvent and dispersant, and then the obtained mixture is ball milled with bond and plasticizer to obtain sizing agent for curtain containing; (7) the sizing agent is formed in a curtain coating way; and (8) and flakes are sliced and sintered to obtain the ceramic piece. The prepared PTC ceramic has the advantages of small crystal grains, small room-temperature resistivity and large PTC effect.

The invention relates to a normal-temperature plastic deformation-rapid solidification magnesium alloy anode material as well as a preparation method and application thereof. The preparation method comprises the following steps that S101, as-cast AP65 magnesium alloy is treated into magnesium chips, grains are refined through high-energy ball milling, and powder is obtained and ground; S102, in avacuum environment, spark plasma sintering is carried out after pretreatment, and the material is obtained, or S201, the as-cast AP65 magnesium alloy is treated into magnesium chips, grains are refined through high-energy ball milling, powder is obtained and ground; and S202, after spark plasma sintering is conducted, heat treatment is conducted under the vacuum condition, and the material is obtained. According to the invention, high-energy ball milling, spark plasma sintering and consolidation technology and the like are adopted, the magnesium alloy anode material is promoted to be rapidly and uniformly dissolved under low current density, and peeling off of a corrosion product is accelerated, so that the discharge voltage of the magnesium alloy is improved, the voltage fluctuation is reduced, stable work of an electric appliance is facilitated, and the comprehensive electrochemical performance of the magnesium alloy anode material is further improved.

The invention discloses a CoCrPt series alloy sputtering target and film and a preparation method thereof. The CoCrPt series alloy sputtering target comprises an element B, wherein the content of the element B is 0-20 atomic percent; the alloy target comprises a Co-enriched phase and a B-enriched phase; the B-enriched phase is uniformly distributed in the Co-enriched phase; the average grain size of the Co-enriched phase is 20-50mu m; and the average grain size of the B-enriched phase is 0-20mu m. The method for preparing the CoCrPt series alloy sputtering target comprises the following steps: (1) performing vacuum melting; (2) performing hot isostatic pressure; (3) performing thermal machining; and (4) performing cold machining. The invention also discloses a magnetic recording medium prepared by using the CoCrPt series alloy sputtering target. The magnetic recording medium comprises a substrate layer, an adhesive layer, a soft magnetic layer, an intermediate layer and a magnetic recording layer, wherein the coercive force of the magnetic recording medium is 3000-5000Oe; and the squareness is 0.80-0.95. The CoCrPt series alloy sputtering target is uniform in chemical components and small in deviated nominal composition, and the technical problems in a conventional preparation process that rolling cracking is caused, the yield is low, the mount of deviated nominal composition of the chemical components of the alloy target is large, the content of harmful impurities is extremely high are solved.

The invention provides a multi-layer and multi-pass composite wire arc additive manufacturing method and system for a metal structure. The multi-layer and multi-pass composite wire arc additive manufacturing method for the metal structure comprises the following steps of: 1, selecting a welding wire and a substrate required for forming a specific metal structural part, and determining technological parameters; 2, generating a multi-layer and multi-pass wire arc additive path of outer wall, short straight line filling and layered turning filling; and 3, enabling a welding gun to move according to the generated multi-layer and multi-pass wire arc additive path under the driving of a robot. The welding gun is driven by the robot to conduct 3D printing according to the generated outer wall, short straight line filling and layered turning filling composite path; the outer wall path improves the size precision of a formed workpiece; the short straight line filling path solves the problem that the heights of complex structural parts are inconsistent in the printing process, and obvious macro buckling deformation is not prone to being formed; and through layered turning filling, interlayer defects are greatly reduced through, and the mechanical property of the workpiece is improved. Digitization, intellectualization and parallelization of part manufacturing are achieved.

The invention discloses a CoCrPt-oxide magnetic recording target, film and a preparation method thereof. The CoCrPt-oxide target includes one or several oxides selected from SiO2, TiO2, CrO, Cr2O3, Ta2O3, W2O3, Al2O3 and Y2O3, wherein the average grain size of the oxides is in the range of 3-20 mum. In the Alloy target, Co, Cr and Pt form an alpha-Co and epsilon Co two-phase Co based solid solution, which mainly comprises low temperature phase hexagonal epsilon-Co solid solution; the target has a thickness in the range of 2-6 mm, and magnetic susceptibility (PTF) value of 40%-60%. A magnetic recording layer of a magnetic recording medium prepared from the alloy target material is in preferred orientation growth of (002) crystal face, and in the X diffraction analysis, the X ray diffraction peak intensity ratio of the (002) crystal plane represented by the formula (1) is 70%-90%. The sputtering target provided by the invention has low content of harmful impurity elements, fine and uniform grain size, homogeneous chemical composition with small deviation from the nominal composition. The magnetic recording medium prepared from the above sputtering target material has uniform and fine grains, clear nonmagnetic grain boundaries, and excellent magnetic properties.

The invention discloses a nanocrystal M-shaped ferrite powder and a synthesis method thereof. The nanocrystal M-shaped ferrite powder is a single M-shaped ferrite powder with the particle size of 65-100nm; in the contained nanocrystal M-shaped ferrite powder, M:Fe:O=1:12:19 and M is Pb, Ba or Sr. The synthesis method of the nanocrystal M-shaped ferrite powder comprises the following steps of: firstly, dissolving citric acid into distilled water; then, adding Fe salt and M metal salt, and sufficiently stirring the mixture until the mixture is dissolved, and adjusting the pH value of the solution to 5-7.5 by using ammonium hydroxide; next, stirring the solution at the temperature of 75-100 DEG C to form a complex solution, and then, controlling the temperature at 60-120 DEG C to form a precursor; and finally, calcining the precursor at the temperature of 850-900 DEG C for 60-120min to obtain the nanocrystal M-shaped ferrite powder. The synthesis method has the characteristics of short synthesis period, high efficiency, low synthesis cost, suitability for mass production and the like; and the synthesized powder nanoparticles are fine and uniform.

The invention provides a same-level multi-strand continuous casting device and method for magnesium alloy. The device comprises a flow guide pipe, a flow diversion box, hot top crystallizers, a flow diversion pipe, a shield gas pipe, a water tank and dummy ingots. The flow guide pipe is inserted in the flow diversion box. The flow diversion box and the hot top crystallizers are fixed to the water tank. The flow diversion box and the hot top crystallizers are connected through the flow diversion pipe. The shield gas pipe is connected with the flow diversion box and the hot top crystallizers. The dummy ingots are arranged under the top hot crystallizers. The method includes the technical steps that firstly, the dummy ingots stretch into the hot top crystallizers to be aligned, a heating sleeve is electrified, cooling water is led into the water tank, and shield gas is led into the shield gas pipe; secondly, a magnesium alloy melt is introduced into the device, a casting machine is started at a preset speed, and casting is conducted; and thirdly, when the preset cast ingot length is nearly reached, casting is stopped. Magnesium cast ingots manufactured through the same-level multi-strand continuous casting device and method for the magnesium alloy are smooth in surface, free of cracks, even in internal texture and even and fine in grain size.

The invention discloses a method for optimizing grain size and uniformity of a tantalum plate. The method comprises the following steps: 1, a tantalum cast ingot with a circular section shape is flattened by using a rapid forging machine in a room-temperature environment to obtain a tantalum blank with a rectangular section shape; 2, saw cutting is conducted, and a tantalum blank with the square cross section is obtained; 3, forging and rounding are conducted after heat preservation, and a bar blank with a circular cross section is obtained; 4, primary annealing treatment is performed to obtain an annealed bar billet; 5, the bar billet is extruded after heat preservation to obtain a plate blank with a rectangular section; 6, secondary annealing treatment is conducted, and an annealed plateblank is obtained; 7, rolling is performed to obtain a plate; and 8, third-time annealing treatment is conducted, and a finished tantalum plate is obtained. By the method, preparation of the medium-thickness tantalum plate with the thickness ranging from 5 mm to 20 mm can be achieved, the grain size is superior to 6.5 levels, the maximum grain size is less than or equal to 38 [mu]m, the grain size of the plate in the thickness direction is uniform, and the grain size level difference between a surface layer and the core portion is within 0.5 level.

The invention provides an automatic trajectory planning method and system for multi-layer and multi-channel wire arc additives of a metal structure. The automatic trajectory planning method comprises the following steps: Step 1, conducting layered slicing treatment on a model of a printed workpiece; Step 2, after obtaining a layered relation matrix, calculating a contour line according to triangles recorded in the matrix by means of a topological relation; Step 3, calculating filling line segments; Step 4, sorting all the intersection points obtained in the Step 3 according to the size of the X coordinate; Step 5, connecting the filling line segments; and Step 6, carrying out layered direction-changing scanning. Multi-layer and multi-channel 3D printing of a metal structural part is carried out according to the composite printing path of outer wall + short straight line filling + layered direction-changing filling, chemical components of a formed workpiece are uniform, the purity is high, and the structure is almost free of anisotropy. Multi-layer and multi-channel 3D printing of the metal structural part is carried out according to the composite printing path of outer wall + short straight line filling + layered direction-changing filling, the grain size of the formed workpiece is small and uniform, the mechanical performance is high, and the level of the formed workpiece can exceed that of a casting with the same component.

The invention discloses a cast ingot uniformizing method for improving the corrosion resistance of a 5083 aluminum alloy plate. The cast ingot uniformizing method for improving the corrosion resistance of the 5083 aluminum alloy plate comprises the steps that a cast ingot is cut to be in a block shape; then the cast ingot is subjected to heat preservation at the temperature of 500-560 DEG C for 4-8 h for homogenizing treatment; the cast ingot is hot-rolled to 8-10 mm; low-deformation cold rolling is conducted for five passes till the thickness of the aluminum plate reaches 4 mm; and after coldrolling, the aluminum plate is annealed, and thus, an O-state 5083 aluminum alloy plate with high corrosion resistance is obtained. By the adoption of the cast ingot uniformizing method for improvingthe corrosion resistance of the 5083 aluminum alloy plate, the problems that during existing industrial production, energy consumption for uniformizing the 5083 aluminum alloy plate is high, the timefor uniformizing the 5083 aluminum alloy plate is long, and the metal oxidization loss is large are solved; and the corrosion resistance of the 5083 aluminum alloy plate treated through the cast ingot uniformizing method is very good.

The invention discloses a preparing method of a strong-strength strong cubic texture layered composite base strip. The preparing method comprises the steps that (1) alloy smelting and hot rolling arecarried out, wherein continuous casting is carried out to obtain a nickel tungsten alloy ingot with the tungsten atomic percentage composition being 12% to 14%, the thickness is 500 mm to 700 mm, rough rolling is carried out until the thickness is 50 mm to 70 mm, according to the process, heat preservation at 1290 DEG C is carried out for 20 minutes, 5-gate machining is carried out, heat preservation is carried out at 1250 DEG C for 20 min, finishing rolling is carried out until the thickness is 12 mm, 3-gate machining is carried out, and water quenching is immediately carried out after the first-gate machining; (2) cold rolling is carried out on a hot rolled sheet, wherein the surface is polished and descaled to be subjected to cold rolling until the thickness is 90 microns to 100 microns; (3) deposition of an alloy film is carried out, wherein magnetron sputtering is carried out on the strip surface for deposition of a Ti-V-Cr-Zr alloy film with the thickness being 30 n, the atomic percentage composition of each element is 25%, the purity is more than 99.9%, magnetron sputtering is carried out on the surface of the film for deposition of a Cu-Ni-W alloy film, the atomic percentage composition of Ni is 35%, the atomic percentage composition of W is 1%-3%, the thickness is 10 nm to 30 nm, and the two films are both subjected to single-face deposition; and (4) heat treatment ofthe alloy film is carried out, wherein according to the heat treatment process of a composite strip, the temperature-reaching furnace-entering annealing manner is adopted, heat preservation is carriedout at 1200 DEG C for 1 min to 3 min, and pure hydrogen annealing is carried out. By means of the preparing method, a high strength layered composite base strip is obtained.