194 results about "Crystal twinning" patented technology

Alloy steels that combine high strength and toughness with high corrosion resistance are achieved by a dislocated lath microstructure, in which dislocated martensite laths that are substantially free of twinning alternate with thin films of retained austenite, with an absence of autotempered carbides, nitrides and carbonitrides in both the dislocated martensite laths and the retained austenite films. This microstructure is achieved by selecting an alloy composition whose martensite start temperature is 350° C. or greater, and by selecting a cooling regime from the austenite phase through the martensite transition region that avoids regions in which autotempering occurs.

PROBLEM TO BE SOLVED: To provide a method for growing a β-f-based single crystal which is less prone to be cracked even when it is worked into a large size and high quality substrate or the like. ŽSOLUTION: The β-Ga<SB>2</SB>O<SB>3</SB>single crystal 8 is allowed to grow in one orientation selected from a-axis <100> orientation, b-axis <010> orientation, and the orientation inclined by 13.7°, determined crystallographically, from c-axis toward a-axis and having an angle of 90° with respect to a-axis by heating a seed crystal 7 and a polycrystalline base material 9 while rotating the crystal 7 and the base material 9 mutually in the opposite directions by using an infrared heating single crystal manufacturing device 1. Ž

There is provided a copper alloy sheet including 1.0 to 3.5 mass % Ni, 0.5 to 2.0 mass % Co, and 0.3 to 1.5 mass % Si, a Co/Ni mass ratio being 0.15 to 1.5, an (Ni+Co)/Si mass ratio being 4 to 7, and a balance being composed of Cu and an unavoidable impurity, wherein in observation results of a crystal grain boundary property and crystal orientation by EBSP measurement, a density of twin boundaries among all crystal grain boundaries is 40% or more and an area ratio of crystal grains with Cube orientation is 20% or more, on a rolled surface.

A nano-class twin-crystal copper material with ultrahigh strength and ultrahigh electric conductivity is prepared by electrolytic deposition technique. The resultant high-purity polycrystal copper material features that its microstructure is composed of nearly equiaxed submicron (300-1000 nm) crystals, and in the crystal there are high-density parallel twin crystal layers with different orientations. Its advantages are high yield strength up to 900 MPa and break strength up to 1086 MPa, and high electric conductivity (1.75+/- 0.02 X to the power -8 ohm.m).

A method for preparing block nano-magnesium alloy by utilizing twinning deformation comprises: magnesium alloy cast ingots or extruded bars are cut into rectangular blocks; compression twin crystal deformation with multiple channels and axes is respectively carried out along three direction of X axis, Y axis and Z axis of the rectangular block at the room temperature; the true strain capacity and the strain rate at every channel are controlled; when the true strain capacities along all the directions are accumulated to reach at least 1.5h, the twin crystal reinforced block nano-magnesium alloy having the average size being less than 0.5mum can be obtained. The method has simple processing technique and equipment requirements as well as convenient operation, and can overcome the problems of incontrollable recrystallization, poor effect of strain accumulation and difficult scale in severe plastic deformation of the prior art when in thinning magnesium alloy crystal grains; the method can be used for preparing large dense superfine grained magnesium alloy material and has good industrial application prospect.

The invention provides a biomedical Mg-Sn-Zn-Mn magnesium alloy and a preparation method thereof. The preparation method comprises the following steps: (1) smelting and casting pure magnesium ingots, pure tin ingots, pure zinc ingots and an Mg-Mn intermediate alloy under the protection of a fusing agent to prepare Mg-Sn-Zn-Mn magnesium alloy ingots; (2) keeping the temperature of the Mg-Sn-Zn-Mn magnesium alloy ingots at 300-400 DEG C for 3-5 hours, and extruding or rolling for predeformation; and (3) performing solution heat treatment to the predeformed Mg-Sn-Zn-Mn magnesium alloy at 400-450 DEG C for 12-28 hours, and performing water quenching, furnace cooling or air cooling to the room temperature. The microstructural characteristic of the prepared alloy is that single phase-Mg grains contain a lot of tiny growth twins; and owning to the presences of the growth twins in the grains, the obdurability of the alloy is effectively increased, the tensile strength is up to 195-238MPa, the elongation rate is up to 23-30% and the hemolysis rate is up to 4.68-7.58%. Therefore, the alloy has the advantages of no toxicity, complete degradability and high obdurability, and can be used as orthopedic internal fixation and implantation materials such as intravascular stents, bone screws and bone plates.

The invention relates to the technical field of rolling of metal composite plates, specifically relates to a method for preparing an aluminum-magnesium-aluminum three-layer metal composite plate by prefabricating a crossed corrugated interface, and aims to solve the technical problems of low composite plate bonding strength and serious texture of a magnesium plate basal plane in a conventional method for preparing the aluminum-magnesium-aluminum three-layer metal plate. According to the technical scheme, the method comprises the following steps: rolling a magnesium plate into a double-faced crossed corrugated shape; then covering two layers of aluminum plates on the upper surface and the lower surface of the magnesium plate; flatly rolling the three layers of plates together; and processing to obtain the three-layer metal composite plate with the upper surface and the lower surface being planes and the middle bonding surface being crossed corrugated. With the adoption of the method, the basal plane texture of a magnesium plate can be effectively weakened, and the bonding strength can be improved. Magnesium with uniform mechanical property can be obtained when the texture strength is obviously reduced, and because a weak and dispersed basal plane texture is obtained, basal plane slippage and twin crystal formation are facilitated during stretching, so that the forming property of the plate is improved.

An electrodeposited nano-twins copper layer, a method of fabricating the same, and a substrate comprising the same are disclosed. According to the present invention, at least 50% in volume of the electrodeposited nano-twins copper layer comprises plural grains adjacent to each other, wherein the said grains are made of stacked twins, the angle of the stacking directions of the nano-twins between one grain and the neighboring grain is between 0 to 20 degrees. The electrodeposited nano-twins copper layer of the present invention is highly reliable with excellent electro-migration resistance, hardness, and Young's modulus. Its manufacturing method is also fully compatible to semiconductor process.

The invention belongs to the field of preparing a steel material and in particular relates to a method for preparing a twin crystal induced plastic steel material with high carbon content. The twin crystal induced plastic steel material comprises the following compositions in the range: 0.2 to 0.49weight percent or 0.55 to 1.5weight percent of C, 10 to 22weight percent or 23.1 to 35weight percent of Mn, less than 1weight percent of Al, less than 1weight percent of Si, less than 0.008 percent of S, less than 0.02 percent of P and the balance being Fe and inevitable impurities. The preparation method comprises the following steps: a plate blank prepared through smelting is subjected to a hot rolling process to obtain a hot rolled sheet in a use state; or the plate blank is subjected to hot rolling and cold rolling to obtain a cold rolled sheet; the sheet is subjected to heat treatment in order that the tensile strength is between 750 and 1,200 MPa, the yield strength is between 230 and 615 MPa, the extension rate is between 45 and 70 percent; and no tough brittle turning point exists at a temperature of more than 100 DEG C. The steel material with high strength and high plasticity has excellent comprehensive mechanical performance, machining performance and forming performance, can be used for a steel rail of a railroad, automobile manufacture, engineering machinery, an oil and gas transportation pipeline, a liquefied natural gas transportation ship, war industry and other industries and has important value and great application space for an automobile industry and a war industry with rapid development.

An electrical connecting element, a method of fabricating the same, and an electrical connecting structure comprising the same are disclosed. The method of fabricating the electrical connecting structure having twinned copper of the present invention comprises steps of: (A) providing a first substrate; (B) forming a nano-twinned copper layer on part of a surface of the first substrate; (C) forming a solder on the nano-twinned copper layer of the first substrate; and (D) reflowing the nano-twinned Cu layer and solder to produce a solder joint, wherein at least part of the solder reacts with the nano-twinned copper layer to produce an intermetallic compound (IMC) layer which comprises a Cu₃Sn layer, This invention reduces the voids formation in the interface between the intermetallic compound and the solder, and then enhances the reliability of solder joints.

The invention provides a synthetic melting body method of growing crystal, using pulling method to seed, shrink neck, and extend shoulder, as the growth at equal diameter, adopting soaking method and/or temperature gradient method. It can grow large-sized high-quality crystals, especially oxide crystals like sapphire substrate crystal, doped or undoped aluminum oxide crystal, aluminate crystal, etc. It has the advantages of adopting pulling, soaking and temperature gradient methods: able to grow large-sized crystals, a little pollution, and able to observe the liquid surface and the growing situation of crystal; able to use the original pulling devices; the crystal quality is good, and has low dislocation density and good integrity and optical uniformity, easy to industrialize.

The invention discloses a preparation method of high-efficiency polycrystalline silicon ingots. The method comprises the following steps: uniformly mixing a silicon sol with a highly pure quartz sand slurry to obtain a mixed slurry, and brushing the internal bottom of the crucible in a polycrystalline silicon ingot furnace with the mixed slurry to form an adhesive layer; brushing the adhesive layer with a nucleation source to form a nucleation source layer, and brushing the upper layer of the nucleation source layer and the inner sidewall of the crucible with a silicon nitride coating; adding a solid silicon material to the crucible, and melting to form a silicon fluid; and controlling the gradient of the temperature of the inside of the crucible to make a bottom-up vertical temperature gradient in the crucible, and opening a heat insulation cover to reduce the temperature of the bottom of the crucible. Polycrystalline silicon ingots prepared through the method have the advantages of high conversion efficiency, fine grains and uniform distribution, and corresponding minority carriers have the advantages of long life, few impurity points, regular crystal boundary distribution and no obvious dendrite and twin crystals.

The invention provides a SEM transmission electron Kikuchi diffraction apparatus and an analytical method. The apparatus comprises the following components: an electron beam irradiation unit for irradiating electron beams on a sample; an electron backscatter diffraction detector and a sample stage which are located below the electron beam irradiation unit; wherein the sample stage is configured, so that an inclination angle is formed between the sample which is carried on the sample stage and a horizontal plane; and the detector is provided with a phosphor screen which is configured for acquisition and reception of transmission electron signals which are emitted by the sample. Clear transmission electron Kikuchi diffraction patterns are obtained, in order to realize phase identification and phase proportion calculation of crystal grains of nanometer scale, analysis of nanometer scale texture and misorientation, analysis of crystal grain size and shape, analysis of crystal boundary as well as properties of sub-grain and twin crystal, etc.

A papermaker's fabric, usable in the forming section of a paper machine, has three layers of cross-machine-direction (CD) wefts. The forming layer wefts are grouped into pairs. This twinning of the top-layer wefts results in non-equal spacing in the forming layer. This spacing imparts a desired non-uniformity in the web-supporting surface, thereby reducing the fabric diagonal problem. One of the top-layer wefts in each pair is vertically stacked with the middle and wear side layer wefts. The other top-layer wefts in each pair are unstacked. This alignment increases the drainage properties of the fabric. The middle layer wefts provide extra stability in the CD.

The invention discloses a preparation method for high-purity flaky alumina, belonging to the technical field of preparation of special powder. The preparation method comprises the following steps: with high-purity aluminum isopropoxide with a purity of 99.999%, pure water and isopropanol as main raw materials and ammonium bifluoride or ammonium fluoride as a crystal morphology controlling agent, dissolving the high-purity aluminum isopropoxide in isopropanol to prepare a solution A; preparing a solution B from pure water, isopropanol and ammonium bifluoride; then gradually adding the solution A into the solution B drop by drop at a certain addition speed; carrying out a reaction under the conditions of heating and stirring so as to produce hydrated alumina; and then successively carrying out filtering, drying and roasting so as to obtain the high-purity flaky alumina. The high-purity flaky alumina prepared by using the method has crystal grain thickness of no more than 1.0 [mu]m, a radial size of 5 to 20 [mu]m, a smooth surface, a flaky shape, no agglomeration and crystal twinning, and good dispersibility, and can be used in fields like cosmetics, pearlescent pigment, high-grade coatings and fine ceramics.

The invention discloses a method for refining magnesium alloy crystal grains, belonging to the technical field of plastic processing of nonferrous metals. According to the method, a magnesium alloy is easily subjected to twin dynamic recrystallization in a low-temperature thermal deformation process by virtue of the processes of twin crystal presetting, low-temperature annealing and low-temperature thermal deformation, and nucleation of new crystal grains is promoted by means of interaction of twin crystals as well as interreaction between the twin crystals and moving dislocation; twin crystal resetting can provide preferred nucleation points, including twin crystal boundaries, boundaries between twin crystals as well as boundaries between twin crystals and crystal boundaries, for dynamic recrystallization in order to accelerate a dynamic recrystallization process and realize refining of crystal grains. The method has the advantages of simple production equipment and low cost, is easy to implement and can be put into mass production.

The present invention provides a process for upgrowth of R surface sapphire to develop crystal with synthetic fused mass method, wherein a czochralski method is adopted for seminationsowing, neck receiving and shoulder putting, and a kyropoulos method and/or temperature gradient technique is adopted during the equal-diameter growth. The equipments and the modes of heating used in the process are not restricted strictly, and a czochralski equipment is adopted usually, which can be used regardless induction heating or resistance heating. Said process possess the advantages of czochralski method, kyropoulos method and temperature gradient technique: it can develop crystal with large size without much pollution, wherein the liquid level and the instances of crystal growth can be observed; it can also adopt the existent czochralski method equipment. At the same time, the process overcomes the shortcomings (such as high color centre and location erroneous rate) of the czochralski method and the temperature gradient technique, can produce crystal with excellent quality, small stress, without slip band and twins defects, with low dislocation density, with excellent crystal perfection and optical homogeneity, easy to its industrialization.

The invention discloses a preparation method of five-twin-crystal decanedron gold-silver alloy particles comprising chloroauric acid, silver nitrate, polyvinylpyrrolidone, water and N, N-dimethylformamide, and the five-twin-crystal decanedron gold-silver alloy particles prepared through the preparation method. The invention further discloses a preparation method of five-twin-crystal gold particles comprising chloroauric acid, the five-twin-crystal decanedron gold particles, polyvinylpyrrolidone, water and N, N-dimethylformamide, and also discloses the five-twin-crystal gold particles with the shape similar to spheroids, the pentagon dodecahedral five-twin-crystal gold particles with all crystal faces being {110} crystal faces, the pentagon-star five-twin-crystal gold particles with a part of crystal faces being {110} crystal faces, and the chamfered-decanedron five-twin-crystal gold particles with a part of crystal faces being {110} crystal faces, wherein all the five-twin-crystal gold particles are prepared through the preparation method. According to the five-twin-crystal gold-silver alloy particles, the preparation method of the five-twin-crystal gold-silver alloy particles, the five-twin-crystal gold particles and the preparation method of five-twin-crystal gold particles, the five-twin-crystal structure and the high-energy {110} crystal faces are combined for the first time, so that the five-twin-crystal gold particles have more physicochemical properties determined by shapes and forms.

The invention relates to a preparation method of silicon carbide nano-wire having periodic twin structure. Biphenyl is dissolved in acetone; nitrate is added and dissolved, tetraethyl orthosilicate is added into the solution and well mixed to be hydrolyzed to form sol; hexamethylene tetramine is added in the sol to form gel and the obtained gel is dried for 5-30h at the temperature of 80-110 DEG C to obtain dry gel; the dry gel is heated to 1200-1400 DEG C to be constantly reacted for 3-20h under the condition of argon, naturally cooled to room temperature, oxidized for 1-6h at the temperature of 600-800 DEG C, pickled by hydrochloride and hydrofluoric acid, then is cleaned by water and dried, and at last the silicon carbide nano-wire having periodic twin structure is obtained. The invention has the advantages of low production cost, low reaction temperature and simple and straightforward technique.

A magnesium alloy comprising up to about one weight percent of cerium may be hot worked to produce an intermediate or final alloy workpiece that exhibits enhanced ductility at room temperature. The addition of a small amount of cerium may affect the magnesium alloy by reducing yield strength, refining grain size, and improving the work hardening behavior. Recrystallization during hot deformation of the rare earth containing magnesium material alters the texture of the alloy and orients the grains in a manner that favors basal slip activity. The alloy thus deforms at room temperature by a combination of twinning and slip mechanisms.

The invention discloses a method for preparing a laminar alpha-Al2O3 pearlescent pigment base material by use of compound aluminum salt. The compound aluminum salt (aluminium potassium sulfate or aluminum sodium sulfate) is selected as the aluminium source, and is hydrolyzed to produce a required fused salt in situ; under the condition of adding laminar alpha-Al2O3 seed crystals and crystal growth regulators (a titanium salt and a phosphate), a gel produced by reaction is dried and calcined at 850-1100 DEG C to prepare laminar alpha-Al2O3 with favorable properties, so that the method is simple in process. The obtained laminar alumina (0.2-0.5 [mu]m in average thickness, 11-15 [mu]m in average particle diameter, larger than 20 in diameter-to-thickness ratio and no clustering or crystal twinning) can serve as the pearlescent pigment base material.

The invention discloses an MCrAlY coating with excellent oxidation resistance and a preparation method thereof. By adopting a plasma-assisted electron beam physical vapor deposition technique and controlling the substrate temperature, the anodal discharge voltage, the evaporation voltage and the bias voltage applied on a matrix, the MCrAlY coating is prepared, and the crystallite dimension of the coating is 10 Mu m to 50 Mu m of isometric crystal structure; the orientation of the coating along a (111) close-packed direction is strong; the twin crystal dimension in the coating is 200nm to 500nm; the Beta phase in the coating is uniformly distributed in the form of strips along the growing direction, moreover, the dimension of the Beta phase is less than 1 Mu m, and a large quantity of phase interfaces are formed. When the coating is used under the temperature of 1150 DEG C, the high-density twin crystals and the phase interfaces provide passages for Al element to quickly diffuse outwards, so that a dense Alpha-Al2O3 protective film can be more easily formed, meanwhile, the destructive effect of the outward diffusion of the matrix element on the oxide film is weakened, and thereby the oxidation resistance of the coating is excellent, and is increased by one order of magnitude compared with the oxidation resistance of the conventional EB-PVD coating.