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65 results about "Grain boundary strengthening" patented technology

Grain-boundary strengthening (or Hall–Petch strengthening) is a method of strengthening materials by changing their average crystallite (grain) size. It is based on the observation that grain boundaries are insurmountable borders for dislocations and that the number of dislocations within a grain have an effect on how stress builds up in the adjacent grain, which will eventually activate dislocation sources and thus enabling deformation in the neighbouring grain, too. So, by changing grain size one can influence the number of dislocations piled up at the grain boundary and yield strength. For example, heat treatment after plastic deformation and changing the rate of solidification are ways to alter grain size.

Castable and forgeable solid solution tungsten alloy and preparation method

The invention discloses castable and forgeable solid solution tungsten alloy and a preparation method, and belongs to the technical field of refractory alloy. According to the chemical components, thecastable and forgeable solid solution tungsten alloy comprises, by weight percentage, 20%-75% of W, 0%-20% of Mo, 0%-20% of Nb, 0%-20% of Ta, 0%-10% of Hf, 0%-10% of V, 0%-10% of Zr, 0%-10% of Ti, 0%-10% of Al, 0%-5% of Cu and the balance Ni or Co and inevitable impurity elements and microelements, specifically, the Ni element and the Co element can be partially replaced by one or two or more elements of 0%-50% of Ir, 0%-30% of Fe, 0%-20% of Cr, 0%-20% of Re and 0%-20% of Ru. The castable and forgeable solid solution tungsten alloy further comprises the following one or two or more grain boundary strengthening elements of 0.001%-1.0% of C, 0.001%-1.0% of B, 0.001%-1.0% of Y, 0.001%-1.0% of La or Ce or the rare earth element, 0.001%-1.0% of Mg and 0.001%-1.0% of Ca. The castable and forgeable solid solution tungsten alloy has the advantages of being high in density, ultrahigh in strength, high in toughness and high in hot-working performance. The alloy is castable and forgeable and canbe formed through 3D printing, the density ranges from 11.0g/cm<3> to 15.0g/cm<3>, the impact toughness is 80J/cm<2> or above, and the tensile strength is 1700MPa or above.
Owner:CENT IRON & STEEL RES INST

Laser cladding alloy powder and laser cladding method for H13 die steel

The invention discloses laser cladding alloy powder and a laser cladding method for H13 die steel. The the laser cladding method comprises the following steps that re-treating is carried out on a matrix before cladding; H13 plus nickel-clad WC alloy powder is prepared for laser cladding; the matrix is preheated; and a laser cladding machine is adopted, argon is used as protective gas, an optical fiber laser is an emitting laser source, the prepared laser cladding H13 plus nickel-clad WC alloy powder through a conical powder beam coaxial powder feeding mode is subjected to multi-channel lap joint to the matrix for laser cladding, laser cladding is carried out by controlling the laser power, the light spot diameter, the scanning speed and the powder feeding speed of laser cladding, and lasercladding of the H13 die steel is modulated and then is completed. According to the laser cladding method, the cladding layer forms a grain boundary strengthening type network structure, and has the characteristics of low friction coefficient, high wear resistance, high corrosion resistance and the like. The problem of dilution rate is reduced, the thermal stress is reduced, the metallurgical bonding with the matrix is increased, and the problem of easy cracking of large-area multi-channel lap joint is solved.
Owner:XIAN UNVERSITY OF ARTS & SCI

Preparation method of high-performance sintered Nd-Fe-B magnet with multi-layer grain boundary structure and prepared product

The invention discloses a preparation method of a high-performance sintered Nd-Fe-B magnet with a multi-layer grain boundary structure and a prepared product, and aims at solving the problems of a single grain boundary strengthening effect, serious waste of heavy rare-earth resources and the like due to the fact that fine control on the grain boundary structure cannot be achieved in an existing method. According to the multi-layer grain boundary structure of the prepared magnet, a heavy rare-earth thin shell distributed on a grain boundary of a main phase has a relatively high magnetocrystalline anisotropy field, so that magnetic domain inversion of a weak area of the grain boundary in a reverse magnetic field can be inhibited, thereby improving the coercivity and the high-temperature stability of the magnet. Meanwhile, the heavy rare-earth thin shell is only distributed on the grain boundary of the main phase and is rarely diffused to the main phase and a center area of the grain boundary, so that the dosage of heavy rare earth can be greatly reduced and the production cost of the magnet is reduced. In addition, an electrode potential difference between a grain boundary phase and the Nd2Fe14B main phase can be reduced through formation of a high-potential grain boundary center layer in the magnet, the electrochemical corrosion drive force is reduced and the corrosion resistance of the magnet is obviously improved.
Owner:MATERIAL INST OF CHINA ACADEMY OF ENG PHYSICS

Preparation method of high-abundance rare earth sintered neodymium-iron-boron magnet capable of regulating and controlling grain boundary multi-layer structure and product prepared by preparation method

The invention discloses a preparation method of a high-abundance rare earth sintered neodymium-iron-boron magnet capable of regulating and controlling a grain boundary multi-layer structure and a product prepared by the preparation method, and aims at solving the problems that the grain boundary strengthening effect is single and waste of heavy rare earth resources is serious due to the fact that fine regulation and control on the grain crystal structure cannot be achieved by an existing method, and limited rare earth resources are greatly consumed along with a dramatic increase in the dosage of the magnet. According to the preparation method, preparation of the high-abundance rare earth sintered neodymium-iron-boron magnet capable of regulating and controlling the grain boundary multi-layer structure is achieved by adopting a double-alloy process and a second sintering technology. The prepared magnet has a double main phase structure and has an Nd2Fe14B main phase and an (La, Nd)2Fe14B/(Ce, Nd)2Fe14B main phase at the same time; and the grain boundary phase has a multi-layer grain boundary structure of a heavy rare earth thin shell layer/a high-potential grain boundary center layer containing high-abundance rare-earth/another heavy rare earth thin shell layer. According to the preparation method, overall improvement of the magnetic property and the corrosion resistance of the magnet is achieved through fine regulation and control on the grain crystal structure on the basis of achieving full utilization of the high-abundance rare earth; and the preparation method has relatively high application value and economic value.
Owner:MATERIAL INST OF CHINA ACADEMY OF ENG PHYSICS

High-nickel ternary positive electrode material as well as preparation method and application thereof

The invention provides a high-nickel ternary positive electrode material as well as a preparation method and application thereof. The high-nickel ternary positive electrode material is prepared from a high-nickel ternary precursor, a lithium source and an additive for improving the grain strength, the additive for improving the grain strength is enriched at the grain boundary; the preparation method comprises the following steps: a) uniformly mixing a high-nickel ternary precursor and a lithium source in a ball mill at a high speed, and introducing an additive for improving the grain strength through low-speed mixing to obtain mixed powder; the speed of the high-speed mixing is 250 to 600 rpm (revolutions per minute); the speed of the low-speed mixing is 50 rpm to 200 rpm; and b) sintering, washing, drying and re-burning the mixed powder obtained in the step a) in sequence to obtain the high-nickel ternary positive electrode material. Compared with the prior art, the additive can be enriched at the grain boundary, the ternary positive electrode material which is strengthened in grain boundary, excellent in particle pressure resistance and good in chemical stability and thermal stability is obtained, and the cycle performance, the DCR performance and the gas production performance of the positive electrode material are obviously improved.
Owner:NINGBO RONBAY LITHIUM BATTERY MATERIAL CO LTD

Hot rolled steel, manufacturing method of hot rolled steel, mooring cable and manufacturing method of mooring cable

The invention provides hot rolled steel, a manufacturing method of the hot rolled steel, a mooring cable and a manufacturing method of the mooring cable. The manufacturing method of the hot rolled steel comprises the steps that raw materials are melted into molten steel, and steel tapping is conducted; the molten steel is refined, constituents of the molten steel are slightly adjusted, and accordingly, the refined molten steel comprises, by weight, 0.20-0.35% of vanadium, 0.020-0.030% of titanium and 0.015-0.020% of nitrogen; the refined molten steel is cast into a cast blank; and the cast blank is rolled and air-cooled into the hot rolled steel. According to the scheme provided by the invention, microalloying (V, Ti and the combination element N of V and Ti are added ) is conducted during steel smelting production, the finish rolling temperature is controlled in the steel rolling process, thus, the precipitation amount of VN and Ti3N4 in the grain boundary and primary-precipitated ferrite is controlled, the purposes of grain boundary strengthening and dispersion strengthening are achieved, and the hot rolled steel with the toughness being identical to that of steel which comprises a large quantity of alloy elements and is subjected to tempering treatment is obtained; and in addition, heat treatment does not need to be conducted in the manufacturing process, the production cost is greatly reduced, and energy consumption is reduced.
Owner:NEW FOUNDER HLDG DEV LLC +2

Preparation method for deforming Al-Mg alloy with ultrahigh Mg content

ActiveCN108330420AImprove solid solution strengtheningEnhanced dislocation strengtheningManufacturing technologyIngot
The invention relates to a preparation method for a deforming Al-Mg alloy with ultrahigh Mg content. The preparation method comprises the following steps of firstly, carrying out component homogenization treatment, densification treatment, and solid solution treatment for forming a single-phase solid solution on an Al-Mg alloy ingot at the temperature of 0-80 DEG C lower than the alloy solidus temperature; then carrying out plastic deformation at the temperature of 20-300 DEG C; and carrying out annealing at the temperature of 50-300 DEG C according to requirements so as to obtain the final deforming Al-Mg alloy with ultrahigh Mg content. Compared with an existing industrialized deforming and casting Al-Mg alloy manufacturing technology, the preparation method has the advantages that solidsolution strengthening, dislocation strengthening and grain boundary strengthening of Mg can be enhanced, and the strength of the Al-Mg alloy can be improved; and compared with a deforming Al-Mg alloy with ultrahigh Mg content prepared through severe plastic deformation and nanocrystalline powder consolidation, the method has the advantages that a large amount of deforming Al-Mg alloys with ultrahigh Mg content can be prepared efficiently at low cost, and a wide industrialization prospect can be achieved.
Owner:WUHAN UNIV OF TECH

Q345B medium-wide band steel and production method thereof

The invention discloses Q345B medium-wide band steel and a production method thereof. The production method comprises the steps of heating, hot rolling, cooling and winding. A steel billet contains the following ingredients by weight percent: 0.14 to 0.19 percent of C, less than or equal to 0.25 percent of Si, 0.45 to 0.85 percent of Mn, less than or equal to 0.035 percent of P, less than or equal to 0.035 percent of S, 0.010 to 0.040 percent of V, 0.004 to 0.015 percent of N, and the balance of Fe and unavoidable impurities. The medium-wide band steel adopts nitrided ferrovanadium to be under microalloying, and the precipitation of vanadium is promoted by increasing the nitrogen, and the crystal grain is refined; trace amount of vanadium is used for substituting a great amount of manganese, and the precipitation strengthening is used for substituting the solution strengthening. The content of Mn in the medium-wide band steel is reduced by about 0.45 percent; meanwhile, by adding V, the cost of the steel per tonnage is effectively reduced; the precipitation strengthening and the fine-grain strengthening are adopted as main strengthening means, so that the content of sulfide impurities is reduced, the internal tissue is improved, and effects for reducing the production cost and improving the quality of the medium-wide band steel product can be achieved. By adopting the method, the addition amount of the alloy element is reduced, the reduction production is realized, the fine-grain strengthening and precipitation strengthening can be better realized, and the comprehensive performance of the product is better.
Owner:HEBEI IRON AND STEEL

Subboundary-reinforced high-strength interstitial free steel containing Ti, and preparation method thereof

The invention belongs to the field of metallurgical technology, and especially relates to subboundary-reinforced high-strength interstitial free steel containing Ti, and a preparation method thereof. The subboundary-reinforced high-strength interstitial free steel comprises 0.12 to 0.16wt% of Mn, 0.08 to 0.10wt% of Ti, the balance Fe and unavoidable impurities. Tensile strength is 540 to 710MPa, and yield strength is 510 to 600MPa. Microstructure of the subboundary-reinforced high-strength interstitial free steel containing Ti is formed by equiaxed ferritic grains, diameter of the equiaxed ferritic grains ranges from 20 to 30 <mu>m, separation distance between geometrically necessary dislocation boundaries ranges from 300 to 500nm, and the size of a cellular structure ranges from 400 to 800nm. The preparation method comprises following steps: Fe, Mn and Ti are subjected to melting and casting so as to obtain ingot casting; the ingot casting is subjected to solution treatment, and hot rolling so as to obtain hot rolled plates; thin steel plates are obtained after further processing; and the thin steel plates are subjected to annealing treatment so as to obtain the subboundary-reinforced high-strength interstitial free steel containing Ti. The subboundary-reinforced high-strength interstitial free steel containing Ti possesses high strength and relatively excellent plasticity and deformability, and possesses significant values for development of the fields of rapid developed automobile industry and machine building industry.
Owner:NORTHEASTERN UNIV
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