44results about How to "Increase nucleation rate" patented technology

The invention belongs to the technical field of laser processing, and particularly relates to a multi-mode laser coupling high-efficiency and high-quality additive manufacturing method for a metal-based composite material, which comprises the steps of pretreatment, substrate pretreatment, multi-mode coupling laser construction, additive manufacturing and the like. High-power pulse laser is adopted as energy supply main laser to melt the metal matrix composite wire, meanwhile, flowing of a molten pool is accelerated, the nucleation rate is increased, and metal matrix composite parts are machined through the additive manufacturing method. The continuous laser is adopted to effectively slow down the cooling speed of the molten pool, and the residual tensile stress generated in the component due to rapid solidification of the molten pool is greatly reduced. Oscillating laser is adopted to improve the shape of a molten pool and reduce the number of times of transverse lap joint. According to the method, multi-mode laser coupling and cooperation with the flat-topped laser light source are utilized, and the metal-based composite material machining part with the uniform and flat surface appearance macroscopically and the stable and uniform organization structure microcosmically is obtained.

The invention belongs to the technical field of additive manufacturing, and particularly relates to a multi-mode laser coupling additive manufacturing method for a high-strength and high-toughness wear-resistant layered part, which comprises the steps of part manufacturing planning, base material pretreatment, multi-mode coupling laser construction, additive manufacturing and the like. Through the laser shaping system and the light path system, the laser light source is shaped into the continuous flat-topped annular laser, the continuous flat-topped annular laser is assisted by the flat-topped pulse laser and the flat-topped oscillation laser for additive manufacturing, the organization structure of a component is homogenized, the nucleation rate in the solidification process is effectively increased, and finally refined crystal grains are obtained; meanwhile, the shape and stress state of the molten pool can be changed, and then the performance of the component is improved. Gradient changes of component components are achieved through cooperative feeding of multiple wires, a workpiece obtains excellent strength, plasticity and toughness, meanwhile, the surface layer of the component is strengthened through a ceramic material, the part obtains extremely high wear resistance, and finally the part with high strength, toughness and wear resistance is obtained.

The invention relates to a preparation method of biphase hard nanoparticle reinforced nodular cast iron applied to lost foam casting. The preparation method comprises the following steps: (1) a synchronous chemical preparation process of TiC-TiB2 biphase hard nanoparticles; and (2) preparing the reinforced nodular cast iron containing the double-phase hard nanoparticles by using an evanescent mode casting process. The preparation method has the advantages that the preparation process is simple, casting equipment and the process are not changed, nano-particles are uniformly dispersed and the like, and the mechanical property and the wear resistance of the obtained nano-particle reinforced nodular cast iron are obviously improved; tiC-TiB2 double-phase hard nanoparticles are added into an evanescent mode model, in the casting process, the nanoparticles gradually enter molten iron along with melting of the model, the nucleation rate of a primary structure of nodular cast iron is effectively increased, grains are refined, and the obdurability of a matrix is improved; the nano-particle reinforced nodular cast iron can be widely applied to the fields of automobiles, mining equipment, ships, infrastructure construction and the like.

The invention discloses a forming method of a flash memory unit. The forming method comprises the following steps: providing a semiconductor substrate; forming a tunneling oxide layer on the semiconductor substrate; forming nanocrystalline silicon particles on the tunneling oxide layer; forming an isolation insulating layer on the tunneling oxide layer and the nanocrystalline silicon particles; and forming a control grid on the isolation insulating layer, wherein the step of forming the nanocrystalline silicon particles on the tunneling oxide layer comprises: forming an amorphous silicon layer on the tunneling oxide layer; and performing repeated seed crystal particle forming processes on the amorphous silicon layer, wherein surface annealing treatment is performed between two adjacent seed crystal particle forming processes, and an annealing process is performed after the last seed crystal particle forming process. The flash memory unit can be used for storing a large quantity of electrons, and has high performance.

The invention relates to the technical field of aluminum alloy materials, in particular to a rare earth microalloyed aluminum alloy cast rod and a production process thereof, and the aluminum alloy cast rod comprises the following chemical components in percentage by mass: 8.0%-9.0% of Zn, 2.2%-2.8% of Cu, 1.8%-2.5% of Mg, 0.005%-0.01% of Ti, 0.005%-0.01% of Si, 0.005%-0.01% of Mn, 0.005%-0.01% of Fe, 0.01%-0.05% of Cr, 0.01%-0.05% of Cl, 0.05%-0.4% of rare earth elements and the balance of Al and inevitable impurities. The rare earth elements are La, Ce and Nd. Rare earth elements in a certain proportion are added into the chemical components, so that the proportion of the alloy components is optimized, and the mechanical property of the aluminum alloy cast rod is improved.

The invention provides a preparation method of a chlorine salt conversion film with high corrosion resistance, which comprises the following steps: dissolving manganese chloride and calcium chloride in water, then adding ammonium dihydrogen phosphate, sodium nitrate and EDTA (Ethylene Diamine Tetraacetic Acid), and carrying out conversion treatment at 50-60 DEG C for 10-15 minutes to obtain a conversion film solution; placing the conversion film solution in a water bath kettle with the temperature of 50-60 DEG C for heating and heat preservation; the magnesium alloy is put into the conversion film solution to form a film for 10-15 min at the film forming temperature of 50-60 DEG C, and a conversion film is formed on the surface of the magnesium alloy; and taking out the magnesium alloy, washing and drying the conversion film, and characterizing. According to the preparation method of the chlorine salt high-corrosion-resistance conversion film, the preparation cost is low, and the prepared film layer is thick and uniform.

The invention discloses a composite plate strip for a water cooling plate, which relates to the technical field of aluminum alloy and comprises the following components in parts by weight: 100-120 parts of aluminum, 5-8 parts of manganese, 2-3 parts of silicon, 8-12 parts of rhenium, 5-10 parts of niobium, 12-16 parts of chromium, 2-5 parts of lanthanum, 2.50-3.50 parts of copper, 0.50-1.50 parts of zinc, 0.60-1.50 parts of strontium and 1.20-1.50 parts of titanium. According to the composite plate strip for the water cooling plate, the components of the aluminum alloy are reasonably adjusted, niobium and aluminum are combined, the aluminum alloy has extremely high chemical stability, lanthanum and strontium are added, in the melting process, lanthanum and strontium are fully combined with the aluminum alloy, lanthanum and strontium are matched, and therefore the heat resistance of the aluminum alloy is improved. And a protective oxidation film is formed on the surface of the aluminum alloy, so that oxidation and corrosion of the aluminum alloy can be effectively prevented, and the corrosion resistance of the aluminum alloy is improved.

The invention provides medium-entropy alloy composite powder for ultrahigh-speed laser cladding, a composite coating and application. The composite powder comprises medium-entropy alloy powder and Ni-coated WC powder. Wherein the mass fraction ratio of the medium-entropy alloy powder to the Ni-coated WC powder is (1-1.5): 1; the medium-entropy alloy powder comprises Fe, Cr, Ni and Ti, and the molar fraction ratio of Fe to Cr to Ni to Ti is 1: 1: 1: (0.4-0.75). The method has the technical effects that the ceramic strengthening phase is added into a medium-entropy alloy powder system, and in the ultra-high-speed laser cladding process, due to the fact that the laser absorptivity and the heat conductivity of Ni in the composite powder are low, the integrity of the WC ceramic phase is effectively protected, the wettability between the WC ceramic phase and a coating is improved through cladding of Ni, and the corrosion resistance of the WC ceramic phase is improved. And the binding force of a contact interface of the two is effectively enhanced, so that the preparation of the high-hardness and high-wear-resistance ceramic phase compounded medium-entropy alloy coating is realized.

The invention discloses a hydrogen engine powder metallurgy valve seat ring and a preparation method thereof, and belongs to the technical field of powder metallurgy manufacturing, the valve seat ring is composed of a Fe-based alloy matrix and a working face magnetron sputtering plating layer, and the valve seat ring is prepared from, by mass, 0.6%-1.2% of C, 4.0%-7.0% of Cr, 0.8%-1.2% of Ti, 0.8%-1.2% of Nb, 2.5%-5.8% of V, 2.0%-4.0% of W, 3.5%-7.0% of Mo, 2.0%-2.5% of Co, 1.5%-2.0% of Mn, 1.0%-2.0% of Al and the balance Fe. 1.0%-1.5% of a solid lubricant and the balance of Fe, and the particle size is 100-120 meshes. The hydrogen engine powder metallurgy valve seat ring has the advantages that the hydrogen engine powder metallurgy valve seat ring is prepared through the warm pressing-die wall lubrication technology and the like, has excellent hardness and strength, high compactness, corrosion resistance, high abrasion resistance, high-temperature performance, hydrogen embrittlement resistance and hydrogen corrosion resistance and is suitable for hydrogen engines of automobiles, ships, military heavy equipment and the like.

The invention discloses a method for preparing an Al-Zn-Mg-Cu aluminum alloy free forging, which comprises sequentially subjecting an Al-Zn-Mg-Cu aluminum alloy ingot after homogenization to variable temperature forging, solution treatment, cryogenic treatment, cold compression treatment and aging treatment. The method can improve the differences in the transverse, longitudinal and high-direction properties of high-strength aluminum alloy free forgings by introducing variable temperature forging technology and combining cryogenic treatment during the forging process, and has the advantages of simple operation and wide applicability.

The invention discloses a method for preparing a high thermal conductivity and low fluid resistance diamond microchannel heat sink, firstly, a dielectric layer film is deposited on the surface of a cleaned polished single crystal silicon wafer substrate, a groove structure with a microchannel frame is formed on the surface of the dielectric layer film by etching using a mask plate with microchannel gate holes; diamond polycrystalline film is epitaxially grown multiple times on the surface of the dielectric layer film with the groove structure, the groove is filled and the dielectric film is covered, and the growth surface of the diamond polycrystalline film is thinned and polished to be flat; the single crystal silicon wafer substrate and the dielectric layer film are removed by pickling or etching, and the nucleation layer of the diamond polycrystalline film is treated by plasma active etching to obtain a diamond wafer with a microchannel structure; finally, a layer of super-hydrophobic amorphous carbon film is deposited on the surface of the diamond microchannel, thereby obtaining a diamond microchannel heat sink with high thermal conductivity and low fluid resistance. The invention comprehensively utilizes the advantages of high thermal conductivity of diamond and super-hydrophobic amorphous carbon-based film, and has significant significance for improving the heat dissipation performance of high-power semiconductor lasers and large-scale integrated circuits.

The invention discloses an electro-gas welding method of a quenched and tempered high-strength steel plate for a large oil storage tank pressure vessel, which comprises the following steps: 1) when high-strength steel is refined, adding a Ca-Mg-Ce alloy block after refining; (2) when a welding test plate is prepared, a V-shaped groove with the angle of 22.5-34.5 degrees is adopted when the thickness size is smaller than 25 mm; an asymmetric X-shaped groove is adopted above 25 mm, the outer side of the groove angle ranges from 23 degrees to 33 degrees, and the inner side of the groove angle ranges from 48 degrees to 69 degrees; (3) assembling the welding test plates, and reserving an assembling gap; (4) electrogas welding is carried out on one side face of the opening face of the V-shaped groove or the outer side face of the asymmetric X-shaped groove, a side face welding seam is formed, and the other side face of the welding test plate is forcibly cooled; and (5) electrogas welding is conducted on the other face, namely the inner side face, of the asymmetric X-shaped groove, an inner side back face welding seam is formed, and a copper water cooling test block with a notch is additionally arranged on the completed outer side face welding seam for forced cooling. A welding joint has excellent low-temperature toughness; and during heat input welding, the three areas of the joint have high impact toughness reserve and safety margin.

The application provides a method for optimizing microstructure of a neodymium-iron-boron magnet rapid solidification sheet by using ultrasonic waves, and belongs to the technical field of neodymium-iron-boron alloy rapid solidification casting sheet. The application applies ultrasonic vibration on a copper roller by using an ultrasonic wave introduction device while the copper roller is rotating, then neodymium-iron-boron alloy melt is cast onto the surface of the copper roller to obtain a neodymium-iron-boron magnet rapid solidification sheet; the initial driving frequency of the copper roller is accurately designed and the amplitude is limited during the casting process, so that the nucleation rate of the magnetic phase grains near the roller surface of the rapid solidification sheet is increased, the growth of the magnetic phase grains in the direction from the near roller surface to the far roller surface is promoted, the magnetic phase columnar crystals are effectively refined, and the uniformity of the microstructure and the thickness consistency of the rapid solidification sheet are significantly improved, so that the effects of improving the nucleation rate and inhibiting the growth of coarse crystals are achieved, and finally the rapid solidification sheet with refined columnar crystals and good orientation is obtained.

The present invention belongs to the field of laser processing technology, and in particular, relates to a method for multi-modal laser coupled additive manufacturing of aluminum alloys, the method comprising the steps of pre-treatment, construction of multi-modal coupled laser, additive process and strengthening treatment. The present invention shapes the laser light source into an annular flat-top laser through a laser shaping system and an optical path system, and uses an annular flat-top pulse laser to assist annular flat-top continuous laser for additive manufacturing, homogenizes the organizational structure of aluminum alloy parts, effectively improves the nucleation rate of the solidification process, and finally obtains refined grains, thereby enabling the workpiece to obtain excellent strength and plastic toughness. An annular flat-top pulse laser is used to strengthen the surface of the processed aluminum alloy, and the residual tensile stress generated by rapid laser solidification is changed into residual compressive stress, thereby obtaining an aluminum alloy workpiece with high strength and high fatigue resistance.

This invention discloses a method for refining primary silicon in Al-Si alloys through synergistic modification with nano-ceramics based on laser additive manufacturing. The method involves uniformly mixing Al-Si alloy powder with TiB2 and Al2O3 nano-ceramics using a ball mill under inert gas protection to obtain a ceramic-reinforced nano-Al-Si alloy composite powder. This nano-ceramic-modified Al-Si alloy powder is then melted and solidified layer by layer using a laser powder bed melting and forming equipment to create the desired target part. In this method, during the solidification of the nano-ceramic-reinforced Al-Si alloy melt, Al2O3 nanoparticles, due to their similarity to the Si crystal structure and the existence of a good interfacial coherence relationship, act as heterogeneous nucleation sites for primary silicon, increasing the nucleation rate and refining the size of primary silicon. TiB2 nanoparticles, distributed at the solid-liquid interface, can to a certain extent prevent the diffusion and aggregation of Si atoms into Si-Si atom clusters, thereby inhibiting the growth of the primary silicon phase, promoting the regularization of the primary silicon morphology and refining its size, and effectively reducing matrix grain size, significantly improving the mechanical properties of the Al-Si alloy.

This invention discloses a high-adhesion, high-temperature resistant composite coating and its preparation method, belonging to the field of surface thin film preparation technology. The method includes: micro-machining and etching a substrate material to form a periodic pattern on the substrate material surface; sandblasting; sputtering a tetrahedral amorphous carbon transition layer film on the substrate material surface; and continuing chemical vapor deposition to deposit a diamond protective film, thereby obtaining a high-adhesion, high-temperature resistant composite coating on the substrate material surface. This method can improve the nucleation rate of diamond on the substrate material and increase the bonding force between the diamond protective film and the substrate material. The tetrahedral amorphous carbon film can be bonded to different materials, such as metals, plastics, and inorganic non-metals, without the serious stress problem during deposition. Using tetrahedral amorphous carbon as a transition layer for the substrate material can increase the stability of diamond on the substrate material and effectively protect the substrate material's anti-oxidation and anti-corrosion properties at high temperatures.

The invention discloses a method for preparing a lightweight semi-solid aluminum alloy die casting for new energy vehicles, and relates to the technical field of semi-solid die castings. The invention adopts a reasonable ratio of elements such as aluminum, magnesium, and silicon, and adopts pulsed airflow to assist stirring to enhance the smelting effect, which can effectively refine the grains and make the crystal phase uniform, which is beneficial to improving the mechanical properties of the die casting. At the same time, there are no bubbles in the melt formed, and the mold cavity can be completely filled; then, metal aluminum, metal nickel, and rare earth lanthanum are used as raw materials to obtain a metal modifier, which is used as a nucleation particle to improve the nucleation rate and purify the interface, and a semi-solid state is initially formed to enhance the mechanical properties of the die casting. Then, a vertical spiral pipe is used as a cooling pipe for secondary cooling. During the cooling process, the spiral blade surface is driven to rotate by the flow of the molten liquid, so as to effectively control the solid phase fraction of the semi-solid slurry, thereby improving the mechanical properties of the die casting.

The present invention discloses a pretreatment trough for semi-continuous casting electromagnetic energy grain refinement, comprising a trough body and a heat-insulating cover arranged on the trough body, two connecting ports are arranged on two opposite trough walls of the trough body, at least one pair of U-shaped silicon steel cores are fixedly arranged on the heat-insulating cover and the trough body, four end posts of each pair of U-shaped silicon steel cores are in the same straight line, a magnetic induction coil is wound around each end post of the U-shaped silicon steel core, and both ends of the magnetic induction coil are connected to a power supply. The present invention is provided with a trough body, a heat-insulating cover and a U-shaped silicon steel core on the trough body and the heat-insulating cover, and a magnetic induction coil is wound around the U-shaped silicon steel core, and a pulse magnetic field is generated after a pulse current is passed through the magnetic induction coil, and the pulse magnetic field instantly generates a large magnetic flux, thereby obtaining pulse electromagnetic energy, which is used to treat the melt and refine the grains of the casting. When in use, the trough body is placed between the flow trough and the casting plate, which can slow down the flow rate and increase the processing time, thereby improving the nucleation rate.

The application discloses a coating material for promoting grain refinement of internal organization of a coating and a preparation method thereof. The method comprises the following steps: drying micron-sized powder, performing ultrasonic dispersion treatment, performing grinding and crushing treatment, mixing the crushed powder with a dispersant I, a binder, a defoaming agent and water to obtain a slurry; performing centrifugal spray drying on the slurry to obtain micron-sized agglomerated particles; uniformly mixing nanometer-sized powder, a solvent and a dispersant II by ultrasonic mixing to obtain a nanometer suspension; adding the micron-sized agglomerated particles into the heated nanometer suspension, uniformly mixing by magnetic stirring, performing solid-liquid separation, cooling the solid, and performing vacuum drying to obtain nanometer-micron composite particles in which the micron-sized agglomerated particles contain nanometer-sized powder; and depositing the nanometer-micron composite particles on a substrate by laser cladding to form the coating material for promoting grain refinement of internal organization of the coating. The method realizes grain refinement of internal organization of the coating and effectively improves the hardness and wear resistance of the coating.

The invention provides a preparation method of an iron-based coating, which comprises the following steps: S1) respectively arranging a laser head and an induction coil on two sides of a sample to be processed, spraying iron-based alloy powder from the laser head, and starting laser cladding from one side of the sample to be processed by the laser head; s2) after the laser head advances 4-6 cm on the surface of the to-be-processed sample, starting the induction coil until the end; and S3) tempering the sample obtained in the step S2). The invention further provides a preparation device of the iron-based coating. According to the preparation method of the iron-based coating, preparation of the iron-based coating is achieved through combination of laser cladding and induction cladding, the problems that the coating is prone to cracking and poor in compactness due to independent laser cladding are solved, generation of defects such as pores and cracks of the coating can be greatly reduced, and the wear resistance and corrosion resistance of the iron-based coating are improved.

The invention discloses a preparation method of an isotropic arc additive manufacturing titanium alloy with fine equiaxed β grains, the method comprising: 1. selecting titanium alloy wire as a matrix alloy, selecting Cu powder, Co powder and Si powder as additives; 2. ball milling and mixing the Cu powder, Co powder and Si powder to obtain a mixed powder; 3. simultaneously feeding the titanium alloy wire and the mixed powder into a molten pool for arc additive manufacturing. The invention promotes the nucleation of a large number of β equiaxed crystals by using β fast eutectoid element Cu, β slow eutectoid element Co and trace element Si to co-segregate at the front of the solid-liquid interface of the arc additive manufacturing titanium alloy molten pool, and limits the growth of β grains during the arc additive manufacturing reheating cycle by rapidly solidifying Ti5Si3, thereby obtaining a titanium alloy with fine equiaxed β grains and almost isotropic. The process is easy to implement, low in cost, wide in application range, short in time, and suitable for industrial production.

The invention discloses a heat treatment process for improving the overall quality of an SJB-4 forge piece, which comprises the following steps: loading the forge piece into a high-temperature heating furnace for primary high-temperature normalizing, then loading the forge piece into the high-temperature heating furnace for secondary high-temperature normalizing, then loading the forge piece into the high-temperature heating furnace for quenching, and then loading the forge piece into a tempering heating furnace for high-temperature tempering, the temperature difference between the surface and the core is reduced through stepped heating, so that the heating stress is reduced, and deformation or cracking caused by overlarge stress is avoided; tissue homogenization is promoted by adopting a two-time high-temperature normalizing mode, rapid cooling is performed after normalizing heating, surface and core pearlite tissue transformation is promoted, and mixed crystals or coarse crystal grains brought by non-equilibrium tissues caused by tissue heredity are cut off; through rapid heating and repeated austenitizing, pearlite with small interlamellar spacing is promoted to be converted into an austenite structure, the nucleation rate is increased, and the grain size is refined; and the quenching cooling strength is enhanced to guarantee the hardenability depth, the austenite-martensite structure from the surface to the core of the forging is promoted, and the quenching uniformity of the forging is improved.

The invention relates to a corrosion-resistant aluminum alloy plate for a new energy automobile battery and a preparation process of the corrosion-resistant aluminum alloy plate, and belongs to the technical field of alloys, the aluminum alloy plate comprises the following components in percentage by mass: 0.50-1.00 wt% of Si, 1.80-2.20 wt% of Mg, 1.10-1.20 wt% of Mn, 0.5-1.0 wt% of Re, 0.15-0.20 wt% of Sc, 0.60-1.20 wt% of La, less than or equal to 0.05 wt% of inevitable impurities and the balance of Al. The corrosion resistance of the aluminum alloy plate is improved through the synergistic effect of manganese, rhenium, magnesium and lanthanum, meanwhile, the lubricant is self-made and is used for preparing the aluminum alloy plate, abrasion of a tool to alloy in the pressing process can be reduced, the quality of the aluminum alloy plate finished product is improved, and the surface attractiveness of the aluminum alloy plate finished product is also improved.

The invention relates to a double-gradient aging treatment method and a preparation method of a high-performance sintered samarium-cobalt permanent magnet, belongs to the technical field of rare earth magnetic materials, and solves the problem that in the prior art, a high-iron samarium-cobalt permanent magnet is limited by at least one factor of squareness and / or maximum magnetic energy product, so that the comprehensive magnetic performance is difficult to improve. The invention discloses a double-gradient aging treatment method for a high-performance sintered samarium-cobalt permanent magnet. The double-gradient aging treatment method comprises the following steps of pre-gradient aging, isothermal aging and post-gradient aging. The square degree and the maximum magnetic energy product of the magnet are improved at the same time, and the magnet shows more excellent comprehensive magnetic performance.

The application provides an electroplating solution and an electroplating method for preparing nanotwinned copper, wherein the electroplating solution comprises copper sulfate, sulfuric acid, chloride ions, a polyether-type inhibitor, a sulfur-containing accelerator, a main twinning inducer and a stress biasing component, the stress biasing component comprises metal ions or metal complexes, the metal ions are not copper ions, and the metal complexes are not copper complexes. The electroplating solution of the application can regulate the dynamic adsorption layer on the cathode surface, the copper nucleation density, the local internal stress and the (111) plane preferred growth by adding the main twinning inducer and the stress biasing component and the like, so that the nanotwinned copper with a high volume fraction can be prepared under the direct current electroplating condition.

The invention discloses a mesoporous material coated carbon fiber, which is prepared by the following method: 1) plasma treatment of carbon fiber electrode; 2) mesoporous material coating; nano silver / carbon film / carbon fiber, wherein the mesoporous material coated carbon fiber is used as a positive electrode, a polypyrrole film is prepared by an electrodeposition method, and carbonization; silver nitrate is added to a 0.1M KNO3 electrolyte to prepare nano silver / nitrogen doped carbon film / carbon fiber; the prepared nano silver / nitrogen doped carbon film / carbon fiber is used as a working electrode, Ag / AgCl is used as a reference electrode, and Pt is used as a counter electrode, a graphene quantum dot water dispersion solution is added to a buffer solution, and graphene quantum dots are deposited on the surface of the material; nano silver / graphene quantum dot / carbon fiber is used as a working electrode, silver nitrate is added to prepare nano silver / carbon film / carbon fiber; the prepared carbon fiber electrode improves the detection range and sensitivity, and reduces the detection lower limit; and can be widely used in electrochemical detection of various substances.

This invention relates to the field of magnesium alloy smelting technology, and in particular to a smelting process and apparatus for a semi-solid non-dendritic slurry of rare earth AS-based magnesium alloy. Using AS magnesium alloy as the base material and a Ce-La-Nd ternary rare earth mixture as the rare earth modifier, the process involves vacuum melting, electromagnetic stirring, and stepped cooling to obtain an ingot. A three-dimensional curve is plotted based on the JMAK equation to determine the critical temperature. Using a rheological casting apparatus, through internal cooling gradient, stirring-assisted slurry preparation, and ultrasonic-assisted isothermal treatment, combined with three-level quality judgment and defect closed-loop adjustment, a slurry with controllable liquid phase content, fine and rounded grains, and uniform rare earth distribution is prepared. The process exhibits high repeatability and meets the requirements of high-end semi-solid forming.

The invention discloses a preparation method of superfine tungsten-nickel-iron composite powder. The method comprises the following steps: 1, carrying out dry mixing, crushing and dispersing on WO3, NiO and Fe2O3 powder; 2, mixing with nano carbon black particles, and drying to obtain a mixture; 3, segmental carbon thermal reduction treatment; and fourthly, the superfine tungsten-nickel-iron composite powder is obtained through deep hydrogen reduction treatment. Nano carbon black particles are used as a nucleating agent and a reducing agent, the nucleation and growth process of reducing WO3 to W is effectively regulated and controlled, the nucleation rate of W is remarkably increased, the particle size of a reduction product is refined, regulation and control of the particle size of the tungsten-nickel-iron composite powder are achieved, and the superfine tungsten-nickel-iron composite powder which is uniform in particle size distribution and high in dispersion is obtained through hydrogen reduction; the method is simple in process, low in cost, suitable for large-scale industrialization and wide in application range, the density of the tungsten-nickel-iron alloy is effectively improved, and preparation of the high-performance tungsten-nickel-iron alloy material is facilitated.

The application relates to the technical field of alloy materials, in particular to a 4341E high-speed steel and a preparation method thereof. The high-speed steel is characterized in that Ti, B and N elements are introduced for ternary micro-alloying and synergistic modification on the basis of a W-Mo-V-Co component system, nanoscale particles generated in-situ by Ti-N are used as heterogeneous cores to significantly refine grains, the grain boundary is strengthened by the grain boundary segregation effect of boron elements, and the reticular carbide is effectively broken. The obtained steel material realizes perfect matching of high hardness, excellent red hardness and excellent impact toughness, solves the problem that the strength and toughness of traditional high-speed steel are difficult to be compatible, and is particularly suitable for manufacturing high-performance cutting tools, cold and hot precision dies and high-temperature wear-resistant parts.