61 results about "Dendrite (crystal)" patented technology

A samarium and cobalt sintered permanent magnet material comprises, in weight percent, 25-27%wt of samarium, 49-51%wt of cobalt, 5-6.5%wt of copper, 3-3.5%wt of zirconium and 15-18%wt of iron. A preparation method includes the steps: smelting; casting an ingot; absorbing hydrogen for the cast ingot; making powder; performing orientation forming and sintering. In the smelting process, the thickness of a casting mould cavity is decreased, cooling water is filled into the wall of the mould cavity, cooling of the cast ingot is accelerated, element composition segregation is decreased, the production process is stabilized, a dendrite crystal is restrained by adding a zirconium element, hydrogen absorbing is performed for the cast ingot in the smelting process, production steps are saved, and energy consumption is reduced. In the subsequent milling process, the cast ingot absorbed hydrogen is crystallized into particles, the particles fracture along crystal boundaries in the milling process of airflow, the integrality of crystal particles is ensured, the anisotropy of the crystal particles is improved, magnetic powder particles are obtained, particle size distribution is concentrated with the range of 3.5-4.5 micrometers, the sintering temperature needed by the magnetic powder particle of each point of a blank is the same in the later sintering process, the sizes of the sintered crystal particles are the same and uniform, and the performances, particularly, such as residual magnetism Br, maximum magnetic energy product (BH) max and critical magnetic field Hk of a sintered permanent magnet are improved.

The invention belongs to the technical field of nickel-based single crystal superalloy preparation, and relates to a method for determining the homogenization / solution heat treatment system of nickel-based single crystal superalloy. Determination of heat treatment temperature for homogenization / solution heat treatment, determination of intermediate level homogenization / solution heat treatment temperature and determination of homogenization / solution heat treatment system. Using the method of the present invention, the alloy can be homogenized / solution heat treated at higher than the as-cast incipient melting temperature without producing incipient melting defects; In the homogenization / solution heat treatment cycle, a better homogenization effect can be obtained without incipient melting defects, thereby effectively solving the serious element dendrite segregation caused by the high content of high melting point elements, the small homogenization / solution heat treatment window, Homogenization is difficult and other problems.

The invention relates to a method for preparing graphene dendritic crystals on an insulating substrate, and belongs to the technical field of microelectronic materials. The method comprises the following steps: cleaning an insulating substrate, and carrying out drying by blowing; placing the substrate into the outer wall of a quartz inner tube in a CVD tube furnace, vacuumizing the tubular furnace, carrying out heating to 200-300 DEG C, introducing hydrogen, and carrying out etching on the surface of the substrate when the temperature is raised to 800-900 DEG C; slowly carrying out heating to1050-1080 DEG C after the etching by hydrogen, keeping the temperature constant, introducing a carbon source and hydrogen, and carrying out graphene growth; stopping introducing gas after the growth is ended, carrying out cooling to 700-800 DEG C first, and then carrying out natural cooling to room temperature. The morphology of the graphene dendritic crystals is of a dendritic shape, and the graphene dendritic crystals are distributed at the top ends of branches. Through the control of the introduction amount of methane, the ratio of the methane to the hydrogen, and the like in the preparation method, the purpose that the graphene grows on the insulating substrate and form a dendritic crystal shape is realized. The dendritic crystal-like graphene has a better mechanical property and electrical property compared with reticulate graphene.

The invention discloses a seed crystal cutting device and a method for casting single crystal superalloys with different crystal orientations, belonging to the technical field of mechanical processing. The seed crystal cutting device consists of two parts: the bottom device that controls and corrects the Gamma angle of the primary dendrite direction and the top device that controls and corrects the Delta angle of the primary dendrite direction, the Alpha angle and the Beta angle of the secondary dendrite direction. X-ray diffractometer was used to measure the angles of the primary dendrite and the secondary dendrite, and the middle angle index of the top device was rotated to determine the corresponding angle for direction correction, and the angle index of the bottom device was rotated to the corresponding angle for direction correction; single crystals were obtained. After the direction of the test bar is accurately corrected, the seed crystal block is cut by the cutting machine, and the obtained seed crystal block is the seed crystal with the [001], [011] or [111] orientation. The seed crystal cutting device can easily and quickly cut single crystal sample seed crystals with different crystal orientations, and improves the yield of seed crystal cutting.

The invention discloses a metal continuous casting process of electromagnetic excitation combined mechanical stirring. When the alloy melt is solidified, the electromagnetic excited combined mechanical stirring technology is used to generate microscopic and macroscale strong shear flow to break dendrites. In this way, the goal of refining the solidification structure, fully equiaxed crystallization, and reducing the degree of solute segregation can be achieved, thereby improving the performance of the alloy. The invention also provides a metal continuous casting device, which is realized by a device composed of a main crystallizer, a rotor stirring paddle, a runner, a program-controlled motor, a magnetic field generator, a coil, and a voltage-regulated and frequency-regulated AC power supply. The present invention uses the microscopic flow generated by electromagnetic excitation and the macroscopic flow generated by mechanical stirring to form a very complex chaotic flow, forming a strong shear flow, breaking dendrites, promoting the proliferation of crystal nuclei, reducing the temperature gradient, and obtaining ultra-fine Fully equiaxed crystal structure, while significantly reducing or even completely inhibiting the segregation of alloy elements, the energy consumption of the present invention is significantly lower than that of conventional electromagnetic stirring, and the energy saving effect is remarkable.

The invention belongs to the field of laser cladding remanufacturing, and particularly relates to a laser cladding abrasion-resistant plate preparation method based on synchronous progressive shear deformation. The method comprises the procedures of surface abrasive blasting, laser cladding, progressive shear deformation and heat treatment, wherein the progressive shear deformation process comprises the steps that to the two ends of a cladding substrate are fixed correspondingly, and one of the ends can move freely in the vertical direction; a ball end cutter moves gradually along a predetermined path, the cladding plate is forced to conduct progressive shear deformation and to attach to a supporting slope; by adjusting the angle of the supporting slope, the degree of shear deformation ofthe cladding plate can be controlled; and the progressive shear deformation process and the laser cladding process are conducted synchronously, and the ball end cutter conducts shear deformation treatment on a recently solidified alloy layer immediately along with a molten pool. According to the laser cladding abrasion-resistant plate prepared through the method, columnar crystals and dendrites which are grown in an oriented mode are broken, fine isometric crystal are fomred, the structure is uniformized, the dislocation density is high, the compactness is good, and the strength and abrasion resistance are high. Meanwhile, the strength of the substrate is improved through shear deformation, the defects of an interface between the laser cladding layer and the substrate are overcome, the bonding strength is improved, and compared with laser cladding wear plates prepared through traditional methods, the laser cladding abrasion-resistant plate has more excellent comprehensive mechanical properties.

The invention provides an Al-Ti-C-Nb intermediate alloy as well as a preparation method and application thereof. The Al-Ti-C-Nb intermediate alloy provided by the invention comprises the following alloy elements in percentage by mass: 1.0-5.0% of Ti, 0.5-2.0% of C and 0.5-2.0% of Nd. By the addition of 0.5-2.0% of Nd, the forming effect of TiC is improved, so that the prepared Al-Ti-C-Nb intermediate alloy has an excellent refining effect. Experimental results prove that when the Al-Ti-C-Nb intermediate alloy provided by the invention is used for refining pure aluminum, a fine equiaxial crystal structure can be obtained by virtue of the addition amount of 0.2wt%, and the grain size is 150-180 microns; and when the intermediate alloy is used for refining hypoeutectic aluminum-silicon alloys, thick dendrite can be enabled to become a fine equiaxial crystal structure of 20-50 microns by virtue of the addition amount of 0.5wt%, and the eutectic silicon is changed from a thick strip form to a fine short-rod or granular structure of 5-10 microns.

The invention relates to a dendritic crystal etchant of a large ingot type modified IN617 alloy and a corrosion method thereof, belongs to the technical field of metallographic sample preparation, andsolves the technical problem that the existing etchant cannot corrode a clear dendritic crystal structure of the ingot type modified IN617 alloy in the prior art. The dendritic corrosion agent of thelarge ingot type modified IN617 alloy comprises 80-120 ml of concentrated hydrochloric acid, 9-15 ml of concentrated nitric acid, 100-130 ml of water and 10-20 ml of ethanol. The etchant provided bythe invention can rapidly and clearly corrode the dendritic structure in the as-cast state and the homogenized heat treatment state of the modified IN617 alloy, measure the dendritic spacing, measurethe components between dendrites and dendrite arms through energy spectrum, analyze the segregation degree of the dendrites, evaluate the elimination effect of the as-cast structure and the homogenized heat treatment of the modified IN617 alloy on the dendritic segregation, and provide an important basis for formulating the homogenization process before forging.

The invention discloses a control method for dendritic crystal spacing in a growth process of a Ni-based single-crystal high-temperature alloy, and belongs to the technical field of single-crystal high-temperature alloys. The method aims to the Ni-based single-crystal high-temperature alloy, and achieves the purpose of controlling the dendritic crystal spacing through adjusting a dendritic crystalgrowth path in the process of directional solidification; and when dendritic crystals of a Ni-based single-crystal casting are coarsened, the method can adjust the dendritic crystal spacing through changing a single-crystal casting growth mode. The method provided by the invention achieves the purpose of controlling the dendritic crystal spacing through adjusting the dendritic crystal growth path, and lays a foundation for preparing single-crystal structural parts with variable cross-section characteristics in the future.

A method for cutting and preparing cast single crystal superalloy seed crystals. Based on the strict correspondence between the growth direction of single crystals and crystal directions, the directions of primary dendrites and secondary dendrites are precisely cut and calibrated, and standard dendrites are constructed based on the dendrite directions. The FCC crystal structure can cut out the (001) crystal plane of the single crystal test rod, and then use the crystal plane angle formula of the FCC crystal to calculate the angle θ between the target crystal plane and the (001) crystal plane, and according to the FCC crystal structure Features Mark the intersection line between the target crystal plane and the (001) crystal plane on the (001) crystal plane, and cut out the target crystal plane along the intersection line with an angle of θ with the (001) crystal plane; cut perpendicular to the target crystal plane A seed crystal with the target orientation is obtained. The invention adopts metallographic observation and directional cutting to directly cut seed crystals with any crystal orientation on cast single crystal test rods, has simple equipment and operation steps, and the orientation deviation of cut out seed crystals is less than 5°.