39 results about "Basal plane" patented technology

The invention relates to a method for constructing a deep learning potential function of a lithium alloy, which comprises the following steps of: establishing initial crystal models of magnesium-lithium alloys with different lithium contents, and carrying out structure optimization on the models to obtain equilibrium state lattice constants; and respectively constructing an elastic constant calculation model, a surface energy calculation model, an interstitial atom defect model and a vacancy defect model. The method comprises the following steps: applying a strain component, calculating a strain energy fitting elastic constant component, calculating surface energy after cutting a supercell structure and optimizing, calculating formation energy after determining a gap position, and introducing a vacancy to form the supercell structure and calculating the formation energy. And inputting the data set into a deep learning framework, optimizing model precision by adjusting truncation radius parameters, and finally generating a magnesium-lithium alloy deep learning potential function. Compared with the prior art, the method has the advantages that the problem that a classic MEAM potential function cannot accurately predict the variation trend of the basal plane fault energy along with the lithium content is solved, the defect of low calculation efficiency of a first principle is overcome, and the calculation efficiency close to that of an empirical potential function is realized.

The invention belongs to the technical field of testing and characterization of semiconductor materials, and particularly relates to a lossless characterization method of semiconductor material-based plane dislocation. Comprising the following steps: preparing a to-be-detected semiconductor material, selecting diffraction geometry according to a BPD (Bourysi vector) of the to-be-detected semiconductor material, and enabling a point product result of the diffraction geometry and the Bourysi vector to be not 0; using an X-ray morphology system to calculate corresponding detection parameters according to diffraction geometry to detect the semiconductor material, and imaging the BPD in the detection range; performing statistical analysis on an imaging result to obtain BPD quantity information in a unit area; or BPD length information in a unit volume is obtained, or a tomography imaging result is obtained. According to the method, non-extinction diffraction geometry is selected for accurate recognition and analysis, nondestructive testing of the silicon carbide material base plane dislocation is achieved, full-coverage imaging can be carried out on a large-size sample, and the destructive problem in a traditional characterization means is avoided.

Inventive techniques for forming unique compositions of matter are disclosed, as well as associated physical characteristics and properties of the materials. In particular, particles comprising a metal lattice are characterized by having carbon (preferably graphene) disposed within the crystalline lattice structure thereof. The carbon is at least partially disposed in interstitial sites of the metal lattice, and may be present in amounts ranging from about 15 wt % to about 90 wt % of the total particle mass, with about 15 wt % to about 60 wt % being disposed in the interstitial sites, e.g., between basal planes, of the metal lattice. The carbon, moreover, is substantially homogeneously dispersed throughout the resultant material, conveying unique and advantageous properties such as strength-to-weight ratio, density, mechanical toughness, sheer strength, flex strength, hardness, anti-corrosiveness, electrical and / or thermal conductivity, etc. as described herein. In some approaches, the graphene is pristine, and has corresponding physical characteristics as described herein.

To enable manufacturing a SiC laminate in which a cubic SiC layer and a hexagonal SiC layer are alternately laminated without a necessity of a strict management of an epitaxial growth condition and a substrate machining profile and a special surface treatment step.SOLUTION: A positive inclined plane and a negative inclined plane that are inclined from a basal plane of a crystal lattice are arranged on a hexagonal SiC surface, and an arrangement of a trail head line, which is a boundary part, is controlled. In addition, a formation of a cubic SiC layer is ensured by providing a trail head line peak protruding in a specific direction. Furthermore, a relative arrangement of multiple trail head line peaks is relatively displaced from an inclination direction and a vertical direction, allowing film thickness control of each SiC layer to be freely performed. Then, a SiC epitaxial growth is performed, allowing to manufacture a SiC laminate in which the cubic SiC layer and a hexagonal SiC layer are alternately laminated.SELECTED DRAWING: Figure 7

The present application belongs to the field of light metal plastic forming, and particularly relates to a device and method for preparing fine-grained magnesium alloy rod by asymmetric multi-directional shear extrusion. The wedge block combination in the present application can combine multi-directional shear extrusion deformation and differential speed torsional deformation, effectively weaken the magnesium alloy basal plane texture, and improve the mechanical properties of the magnesium alloy. While the magnesium alloy material is subjected to torsional extrusion in the torsional extrusion deformation zone, the sectional area of the channel gradually decreases, and the angle of the channel deflection is different, so that the frictional force of the magnesium alloy material on the surface of the convex and concave dies at the contact position is different, and the degree of torsional deformation is also different, so that the material realizes differential speed torsional deformation, and the grain refinement effect of the magnesium alloy rod is more remarkable. When the magnesium alloy material passes through the large and small concave dies, the deformation degrees of the magnesium alloy material are different due to the particularity of the structure, so that the grain refinement is effectively realized. At the same time, the flowability of the magnesium alloy material is also different, causing differential speed flow to deflect the c-axis, thereby weakening the texture.

The application discloses a method for improving the impact resistance and explosion resistance of a titanium alloy. The titanium alloy plate has an elongated macrostructure feature, the basal plane pole points of which are uniformly distributed in a plane perpendicular to the impact direction, and the overall {10-10} and {11-20} crystal face pole patterns have a uniform distribution feature. The preparation process comprises the following steps: forging blank selection, forging blank heating and pretreatment, square shaping, spread forming, multi-fire rolling, and solid solution aging heat treatment. According to whether the original forging blank has a specified organizational form, different high-temperature heating, holding and shaping systems are used to control and stabilize the macrostructure, alpha and beta two-phase structure and texture distribution of the plate. The titanium alloy plate prepared by the above process has good organizational stability, texture uniformity and impact damage resistance.

Provided are a method for manufacturing a silicon carbide single crystal, and a silicon carbide single crystal ingot which ensure a high crystal growth rate and increase the ratio of conversion from basal plane dislocations to threading edge dislocations. The method prepares a seed substrate composed of silicon carbide having an off-angle in a [1-100] direction with respect to a {0001} plane; and grows a silicon carbide single crystal layer on the seed substrate by an HTCVD method, thereby converting basal plane dislocations contained in the seed substrate to threading edge dislocations during crystal growth.

Provided are a method for manufacturing a silicon carbide single crystal, which can suppress conversion of threading edge dislocations into prismatic plane dislocations and conversion of the prismatic plane dislocations into basal plane dislocations; and a silicon carbide single crystal ingot and a silicon carbide wafer, in which conversion from threading edge dislocations into prismatic plane dislocations and conversion from the prismatic plane dislocations into basal plane dislocations have been suppressed. A silicon carbide single crystal is grown on the surface of a seed substrate by a gas method so that a temperature gradient in the radial direction of the seed substrate takes a predetermined value or lower during the growth. The area of regions T1 to T4, where regions R1 to R3 of a basal plane whose shear stresses exceed critical resolved shear stress, and regions S1 to S4 of a prismatic plane whose shear stresses exceed critical resolved shear stress overlap, is less than a half of the area of a crystal growth surface. Furthermore, the area of the regions T1 to T4 is smaller than the area of regions V1 to V4 where a region R4 of the basal plane whose shear stress does not exceed the critical resolved shear stress overlaps the regions S1 to S4.

The invention discloses a method for obtaining a basal plane uniaxial texture in a pure zirconium plate through one-way rolling. The method comprises the following steps: sequentially polishing a pure zirconium plate sample to be bright step by step by adopting different numbers of abrasive paper, cleaning and drying; the sample is subjected to vacuum tube sealing treatment and then subjected to a heat treatment process, the temperature is increased to 950-1050 DEG C at the speed of 4-6 DEG C / min and stabilized for 9-11 min, then the sample is placed in the furnace to be subjected to heat preservation for 1-1.2 h, and the sample is taken out to be subjected to air cooling after the heat preservation time is reached; rolling treatment is conducted on the pure zirconium plate sample, the rolling strain rate is 10-20 s <-1 >, the single-pass rolling reduction is 0.1-0.15 mm, the total rolling reduction is 20-50%, and the rolling temperature range is 0-25 DEG C. According to the method, a pure zirconium plate sample is subjected to heating and heat preservation (in a complete beta-phase region) and then is subjected to air cooling treatment, so that a disordered oriented thick lath structure is obtained; and in the rolling deformation process, a large number of {10-12} and {10-22} twin crystals can be generated and act together with dislocation slippage, and the orientation of original crystal grains is remarkably changed, so that a basal plane uniaxial texture which cannot be generated by conventional rolling machining is obtained.

The application discloses a titanium alloy extruded pipe blank with gradient texture and a preparation method thereof. The titanium alloy extruded pipe blank with gradient texture has gradient texture characteristics in the wall thickness direction, including a surface layer region: within a depth range of 0-1.5 μm from an outer surface and / or an inner surface, a {0001} basal plane strong shear texture is formed, and the crystallographic orientation of the region has an included angle of 30°-60° with the radial direction; a core region: a wall thickness center region, the texture strength is weak, and the texture strength is randomly distributed or weak; a transition region: between the surface layer region and the core region, the texture strength changes in a gradient manner; and a maximum pole density difference of the surface layer and the core region is greater than or equal to 4. Through the gradient texture design, the surface layer of the pipe blank forms a strong shear texture, has high crack resistance, the core region keeps random texture, and provides isotropic high plastic deformation capacity. The performance zoning enables the pipe to withstand a larger deformation amount without being prone to cracking in the subsequent cold working process.

The invention discloses an in-plane texture heterogeneous magnesium alloy and a preparation method thereof. The preparation method of the in-plane texture isomeric magnesium alloy comprises the following steps: (1) preparing a basal plane texture magnesium alloy plate; and (2) rolling the base texture magnesium alloy plate in the step (1) by using a roller-shaped rolling die to obtain the base texture magnesium alloy plate with the deformation of 3-8%, a main body of the roller-shaped rolling die is a roller, and a plurality of protrusions (2) which are evenly distributed in an array mode are arranged on the outer surface of a roller body (1) of the roller. According to the method, multi-pass deformation, complex intermediate / subsequent annealing and expensive special equipment are omitted, the process is extremely simple, the cost is extremely low, the huge potential of large-scale and low-cost industrial production is achieved, and the problems that in the prior art, the process is complex, the cost is high and the efficiency is low are solved.

The present invention provides a SiC substrate capable of reducing cracks and cracks during substrate processing such as grinding, polishing, and cutting. The SiC substrate is provided with a biaxially oriented SiC layer, and the SiC substrate and the biaxially oriented SiC layer have an off-angle. In the SiC substrate, in an X-ray topography (XRT) image obtained by performing X-ray topography (XRT) measurement on a certain 4-square region in the biaxially oriented SiC layer, the ratio of the number of BPDs in which the absolute value on the acute angle side of the angle formed by the progression direction of basal plane dislocations (BPD) and the [11-20] direction is 15 degrees or less to the total number of BPDs is 60% or more. The direction of progress of the BPD is defined as the direction of a line segment in which an end point of the BPD observed to be linear and a point separated from the end point by 150 [mu] m along the linear BPD are linked in the XRT image.

The invention relates to the technical field of laser cladding, in particular to a method and a system for predicting the size of a laser cladding cross section of an inclined base plane. Aiming at the problems of fracture, holes, noise and the like of the cladding layer boundary in a deep learning model prediction result, the invention provides an end point extension repair algorithm based on graph structure analysis, and boundary defects are effectively repaired through the steps of morphological operation, connected domain analysis, path reverse extension and the like. In order to improve the cladding layer section prediction precision, a Pix2Pix model is applied to cladding layer section form prediction for the first time, and perception loss is introduced to enhance the perception ability of the model to boundary details and a global structure. Besides, structural similarity indexes are introduced, molten pool images with high similarity are extracted from molten pool videos under different parameter conditions to serve as an extended training set, and the generalization ability and robustness of the model are effectively improved.

A method of preventing basal plane dislocations (BPDs) from expanding from a SiC substrate or a highly doped buffer layer into an epitaxial device / active layer comprising the steps of providing a substrate, etching the substrate, converting BPDs to electrically benign threading edge dislocations, growing a first buffer layer on the substrate, creating a growth interrupt layer or second etch layer, growing a second buffer layer, growing a drift layer, and preventing BPDs from expanding into the drift layer. A device capable of preventing basal plane dislocations (BPDs) from expanding from a SiC substrate or a highly doped buffer layer into an epitaxial device / active layer comprising a substrate, a first buffer layer, a growth interrupt layer or etch layer, a second buffer layer and a drift layer. The drift layer carrier lifetime is not reduced. BPD expansion is prevented at current densities up to 12 kA / cm2.

To reduce "BPD" in a buffer layer.SOLUTION: When the basal plane dislocation concentration in the buffer layer is equal to or more than 0cm - 2 and less than 5cm - 2, the buffer layer of the product substrate is formed under the same condition as the film formation condition when the buffer layer is formed on the inspection substrate. In the inspection method described above, the wavelengths of the exciting light are equal to or less than 386nm. The integrated illumination of the exciting light is 1. 6W. cm - 2. sec or more. The photoluminescence light is received via a light receiving filter. The light-receiving wavelengths are equal to or longer than the wavelengths of the exciting light and equal to or shorter than the 399nm.SELECTED DRAWING: Figure 4

Ion implantation in which an ion beam (10) comprising nitrogen ions is implanted into a substrate (12) is used to reduce the effects of basal plane dislocations in the substrate (12). The substrate (12) is at least partially formed from SiC in the region (14, 16, 21) to be doped or the regions to be doped. The doping concentration (c) of nitrogen doping atoms that are added to the substrate (12) as a result of irradiation with the ion beam (10) is between 1E14cm-3 and 5E17cm-3 in each region (14, 16, 21) to be doped.

The invention discloses an epitaxial growth method and an epitaxial structure. The epitaxial growth method comprises the following steps: providing a substrate; growing a composite buffer layer on the substrate, wherein the composite buffer layer comprises a first buffer layer and a second buffer layer which grow alternately; and growing an epitaxial layer on the composite buffer layer, the carbon-silicon ratio of the first buffer layer being greater than the carbon-silicon ratio of the second buffer layer. The conversion efficiency of base plane dislocation can be improved through the composite buffer layer, and the electrical performance of the epitaxial structure can be improved.

The present invention provides a bonding wafer structure and a manufacturing method thereof, wherein the bonding wafer structure comprises a support substrate, a bonding layer, and a silicon carbide layer. The bonding layer is formed on the surface of the support substrate, and the silicon carbide layer is bonded to the bonding layer, wherein the carbon surface of the silicon carbide layer is in direct contact with the bonding layer. The basal plane dislocation (BPD) of the silicon carbide layer is 1000 ea / cm 2 ~20000ea / cm 2 The total thickness variation (TTV) of the silicon carbide layer is greater than the total thickness variation of the support substrate, and the diameter of the silicon carbide layer is equal to or smaller than the diameter of the support substrate. The bonding wafer structure has a TTV of less than 10 μm, a bow of less than 30 μm, and a warp of less than 60 μm.

The present invention provides a SiC substrate capable of reducing cracking and cracking during substrate processing. The SiC substrate is provided with a biaxially oriented SiC layer, and when the entire region of an XRT image obtained by X-ray topography (XRT) measurement of the biaxially oriented SiC layer is divided into a lattice shape in which a region having a longitudinal direction of 4 mm * a transverse direction of 4 mm * a depth of 28 [mu] m is given per lattice, X (cm / cm < 3 >) represents the average volume density of basal plane dislocations (BPD) per lattice, and X (cm / cm < 3 >) represents the average volume density of the basal plane dislocations (BPD) per lattice. There are no continuous 10 cells or more on one vertical and horizontal straight line in a region that reaches 5X (cm / cm < 3 >) or more per cell.

There is provided a SiC substrate including a biaxially oriented SiC layer, wherein, in an XRT image obtained by subjecting the biaxially oriented SiC layer to X-ray topography (XRT) measurement, when the entire XRT image is divided into a lattice pattern giving a region of 4 mm longitudinal length×4 mm lateral length×28 μm depth per square and an average value of a volume density of basal plane dislocations (BPDs) per square is defined as X (cm / cm3), regions having 5X (cm / cm3) or more per square do not extend for 10 or more continuous squares in a straight line in either a longitudinal or lateral direction.

A SiC epitaxial wafer according to the present embodiment includes: a SiC substrate; and a SiC epitaxial layer deposited on the SiC substrate, wherein, in the SiC substrate, a density of basal plane dislocations is 1 / cm2 or more and 3000 / cm2 or less, and wherein, in the SiC epitaxial layer, a density of double Shockley (2SSF) type stacking faults is 4 / cm2 or more and 10 / cm2 or less, and a density of stacking faults other than the double Shockley (2SSF) type stacking faults is 2 / cm2 or less.

The application discloses a method for regulating magnesium alloy basal precipitates, and belongs to the technical field of magnesium alloys. The method comprises the following steps: melting and casting raw materials according to a preset Mg-Gd-Y-Zn-Mn alloy composition and content, and then performing rapid solidification and artificial aging treatment; the Mg-Gd-Y-Zn-Mn alloy comprises 8.67%-8.89% of Gd, 3.85%-3.95% of Y, 3.28%-6.47% of Zn and 0.96%-1.96% of Mn in terms of mass percentage, and the balance is magnesium and inevitable impurities; and (Gd+Y):Zn=1:1 or 2:1 in terms of atomic percentage. According to the above method, high-density gamma'' basal precipitates are maintained during peak aging and overaging, and the process window for forming high-density distributed gamma'' basal precipitates in the Mg-Gd-Y-Zn-Mn alloy is effectively increased.

There is provided a SiC substrate including a biaxially oriented SiC layer, and the SiC substrate and the biaxially oriented SiC layer have an off angle. With regard to this SiC substrate, in an XRT image obtained by subjecting a certain 4 mm-square region in the biaxially oriented SiC layer to X-ray topography (XRT) measurement, with respect to a total number of basal plane dislocations (BPD), a percentage of the number of BPDs such that an absolute value of an acute angle between a BPD extension direction and the [11-20] direction is 15° or less is 60% or more. The BPD extension direction is defined as a direction of a line segment connecting an end point of a BPD observed as a linear shape and a point 150 μm away from the end point along the linear BPD in the XRT image.

The present invention provides a silicon carbide wafer and a preparation method thereof. The silicon carbide wafer has no small-angle grain boundaries formed by aggregation of basal plane dislocation defects within an area of ​​5 mm from the edge of the silicon carbide wafer, and the curvature of the silicon carbide wafer is less than 15 μm.

The present invention discloses a method for constructing a deep learning potential function for magnesium-lithium alloys. The method includes obtaining the lattice constants and elastic constants of magnesium-lithium alloys with different concentrations in a stable state through high-throughput density functional theory calculations; obtaining the surface energy of different crystal planes of magnesium-lithium alloys and the generalized stacking fault energy curves of different slip systems to obtain the energy and atomic force information of all configurations; and using the deep learning software DeePMD-kit to train and test the DFT data set, and fitting a deep learning potential function model for Mg-Li alloys. The present invention adopts the above-mentioned method for constructing a deep learning potential function for magnesium-lithium alloys, and the obtained Mg-Li potential function model is consistent with the DFT calculation results in predicting the trend of basal plane stacking fault energy changing with Li atomic concentration, solving the problem that the classical MEAM potential function cannot accurately predict the trend of basal plane stacking fault energy changing with Li concentration.

The invention discloses a silicon carbide crystal growth device. The silicon carbide crystal growth device comprises a growth container; the powder container is suitable for containing silicon carbide powder, the powder container is arranged in the growth container, and a containing space is formed between the outer circumferential surface of the powder container and the inner circumferential surface of the growth container; the flow guide cylinder comprises a plurality of arc-shaped flow guide parts which can be mutually separated in the circumferential direction, the flow guide cylinder is supported on the upper end face of the powder container, and each arc-shaped flow guide part can move in the radial direction and is constructed to be suitable for sliding to the containing space from the upper end face of the powder container under the pushing of growing polycrystals. According to the silicon carbide crystal growing device, the dislocation defect density of a crystal basal plane can be reduced, an annealing process and growing temperature do not need to be sacrificed, and the silicon carbide crystal growing device has the advantages of small crystal defects, high production efficiency and the like.

A single-crystal silicon carbide wafer (31) of the present invention includes boron at a concentration of 1.0×1016 atoms / cm3 or less, and has a central region (33) whose basal plane dislocation density is 100 / cm2 or less on the surface. The central region (33) includes the center of the surface of the single-crystal silicon carbide wafer (31). An area of the central region (33) is one fourth or more of an area of the surface of the single-crystal silicon carbide wafer (31).

A silicon carbide epitaxial substrate includes a silicon carbide substrate, a silicon carbide epitaxial film. The silicon carbide epitaxial film is on the silicon carbide substrate. The first extended defect is in the silicon carbide epitaxial film. The first extended defect includes a particle, a triangular defect extending from the particle along an off-direction, and a basal plane dislocation originating from the particle and having a portion extending along a direction perpendicular to each of a thickness direction of the silicon carbide substrate and the off-direction. In the direction perpendicular to each of the thickness direction of the silicon carbide substrate and the off-direction, an extended width of the basal plane dislocation is twice or more a base width of the triangular defect. In a second main surface, an area density of the basal plane dislocation included in the first extended defect is 3 / cm2 or less.

To provide a SiC epitaxial wafer capable of estimating the density of basal plane dislocation in a SiC substrate in a nondestructive manner.SOLUTION: A SiC epitaxial wafer according to the present embodiment includes a SiC substrate and a SiC epitaxial layer deposited on the SiC substrate, wherein the SiC substrate has a basal plane dislocation density of 1 dislocation / cm2 or more and 3000 dislocations / cm2 or less, and the SiC epitaxial layer has a double Shockley (2SSF) type stacking fault density of 4 dislocations / cm2 or more and 10 dislocations / cm2 or less and has a stacking fault density other than the double Shockley (2SSF) type stacking fault density of 2 dislocations / cm2.SELECTED DRAWING: Figure 1

Provided is a method capable of simultaneously producing multiple sheets of an SiC single crystal substrate having a small amount of warpage, a low basal plane dislocation density, and a large crystal growth thickness. This method involves: a step for preparing a plurality of containers; a step for arranging, in each of the containers, an SiC single crystal as a seed crystal and SiC powder mixture containing SiC powder and a liquid phase generation aid so as to form an SiC powder mixture layer in which the SiC powder mixture is in contact with at least one plane of the SiC single crystal, wherein the liquid phase generation aid contains an oxide; a step for arranging the containers so as to be aligned with each other in the horizontal direction and / or the vertical direction in a firing furnace; and a step for heating the inside of the firing furnace so as to form a temperature gradient in which the temperature is increased or decreased from an upper portion toward a lower portion to subject the containers containing the seed crystal and the SiC powder mixture to heat treatment at an average furnace temperature of 2240-2560°C, thereby growing the SiC single crystal on the seed crystal.