1161 results about "Brittleness" patented technology

The invention discloses a brittle material laser cutting thermal stress control method and system, and the method comprises the steps: obtaining real-time temperature distribution through infrared thermal imaging, combining finite element analysis and material characteristic dynamic data, constructing a thermal stress and fracture relation model, carrying out the iterative calculation of a thermal stress out-of-control threshold through a lambda algorithm, and determining a regulation boundary condition. According to the boundary condition, laser parameters are optimized, synchronous cooling airflow is introduced, the temperature gradient is dynamically controlled through an airflow pressure adjusting algorithm, historical data are processed through a convolutional neural network, the optimal laser parameter combination is predicted, in the cutting process, the microcrack diffusion state is monitored in real time, and auxiliary technological parameters are finely adjusted when necessary. The problem of fracture caused by out-of-control thermal stress in laser cutting of the brittle material is effectively solved, the cutting quality and efficiency are improved, and a new technical scheme is provided for precision machining of the brittle material.

The invention discloses a 340MPa grade P-containing hot-dip galvanized iron alloy high-strength IF steel, the chemical composition of which is as follows by weight: C: ≤0.003%, Si: ≤0.03%, Mn: 0.35-0.65%, P: 0.03-0.075%, S≤0.010%, Als: 0.020-0.045%, Nb: 0.008-0.015%, Ti: 0.02-0.03%, B: 0.0004-0.0010%, N≤0.0035%, and the remainder is Fe and unavoidable impurities; The elements also meet the following restrictions: calculated according to the corresponding weight percentage of each element, 10C+3N+2S≤Ti+2Nb≤12C+3N+2S, 60B≤P≤80B; the present invention adds P element to IF steel, and through composition and process optimization control, obtains a P-containing hot-dip galvanized iron alloy high-strength IF steel with a yield strength of 180-320 MPa, a tensile strength of 340-440 MPa, an elongation of 35-46%, a value (average plastic strain ratio) ≥1.8, high surface quality, high formability, and good cold brittleness.

The invention provides an analysis method and system for dynamic fracture of a quasi-brittle material. The method is used for solving the technical problem that an existing method is insufficient in dynamic fracture capturing capacity in quasi-brittle materials. The method comprises the following steps: constructing a representative volume element RVE of a quasi-brittle material with two embedded fracture planes; a dual-scale model of the RVE is constructed, the dual-scale model comprises a macroscale sub-model and a mesoscale sub-model, and the crack traction force and the displacement jump increment in the mesoscale sub-model meet the rate-dependent cohesive friction law; identifying the parameters of the dual-scale model; and embedding the dual-scale model into finite element software to simulate the dynamic fracture of the quasi-brittle material. The contained mesoscale crack plane has the key characteristics of the dynamic fracture behavior of the quasi-brittle material, and has remarkable advantages compared with a classical empirical model.

The invention relates to a 1100MPa-grade high-strength tool steel wire rod and a manufacturing method thereof, the wire rod adopts a middle-carbon Nb-V-containing chemical component design, after a steel billet is rolled and spun into the wire rod according to the spinning temperature of more than or equal to 860 DEG C, online molten salt semi-quenching isothermal treatment is performed, the wire rod is controlled to be subjected to front-section molten salt treatment, and then the steel wire rod is subjected to hot rolling and hot rolling to obtain the 1100MPa-grade high-strength tool steel wire rod. According to the method, the steel wire rod enters a bainite phase region from a high-temperature austenite state at the cooling speed of more than or equal to 30 DEG C / s to form a structure taking quenched bainite as a main component, and then is subjected to rear-section molten salt heating isothermal tempering and toughening destressing treatment, and finally is subjected to roller way slow cooling to prepare the steel wire rod with a microscopic structure comprising tempered bainite and ferrite, so that the material cost can be reduced, and the production efficiency is improved. The method has the advantages that martensite brittle structures are effectively avoided, the structure state of the hot-rolled wire rod is controlled, the plasticity and cold working performance of the wire rod are improved, the tensile strength of the product can reach 980-1030 MPa, the percentage reduction of area is 61%-66%, and the product can be directly machined into tool parts after cold forming.

The invention discloses a dissimilar metal friction welding interface regulation and control layer and an aluminum steel friction welding method. The dissimilar metal friction welding interface regulation and control layer comprises a micro-texture arranged on the metal surface, paste is laid at the micro-texture, and non-metal substances in the paste are completely volatilized before dissimilar metal metallurgical bonding; the welding method comprises the steps that a microstructure is prepared in a designated area on the surface of a stainless steel plate, Zn-20Al powder and ethyl alcohol are mixed and stirred into paste, then the paste is evenly laid on the microstructure area on the surface of base metal, and then friction stir welding is conducted. A welding joint obtained through the scheme is good in toughness (plasticity) and high in strength, atomic-level tight combination of a joint interface is achieved, the mechanical property of the joint is excellent, the joint is free of air hole and crack defects, the adverse effect of brittle intermetallic compounds on the mechanical property is weakened, the wetting spreading performance and the element diffusion capacity of the interface are enhanced, and the welding quality is improved. The obtained welding joint has a good mechanical embedding characteristic.

The invention provides a high-entropy alloy intermediate layer for GH5188 instantaneous liquid phase diffusion bonding and a bonding method of the high-entropy alloy intermediate layer, and relates to the technical field of metal welding, the high-entropy alloy intermediate layer is composed of Co, Ni, Cr, Al, Ta, Ge, Zr and Y according to the atomic ratio of 25: 20: 20: 15: 10: 5: 3: 2, and the element purity is larger than 99.99 wt.%. The invention further provides the bonding method of GH5188 instantaneous liquid phase diffusion bonding. The high-entropy alloy intermediate layer is arranged in the middle of the base metal GH5188 and is arranged in the vacuum diffusion welding furnace for welding, and compared with conventional instantaneous liquid-phase diffusion bonding, formation of brittle compounds can be inhibited, and improvement of the comprehensive performance of an interface is facilitated.

The invention belongs to the technical field of high-performance cutter coatings, and relates to a cross-scale bionic gradient coating design method based on a multi-principal-element high-entropy system, which comprises the following steps: sequentially forming a high-entropy alloy plastic layer, a high-entropy alloy / high-entropy ceramic tough layer and a nanocrystalline high-entropy ceramic superhard layer on the surface of a cutter matrix, and constructing a gradient transition structure; the method comprises the following steps: matching a high-entropy alloy plastic layer with a tool matrix binding phase, optimizing a high-entropy alloy / high-entropy ceramic tough layer material, improving interface binding force, optimizing gradient transition design by adopting thermal-mechanical coupling calculation, constructing an atomic model, simulating and optimizing a microstructure based on molecular dynamics, and establishing a finite element model to simulate thermal cycle and mechanical load. The interface performance is optimized, a mathematical model is constructed through a BP neural network and a particle swarm optimization algorithm, and gradual transition design of the tool base body and the coating is achieved. The problems that the tool coating interface is high in brittleness, insufficient in adhesiveness, limited in thermal stability and the like are solved, and the bonding performance of the coating interface and the stability and durability of the coated tool are improved.

The invention belongs to the technical field of iron-based material preparation, and particularly relates to a method for optimizing soft magnetic performance of an iron-based amorphous alloy through cyclic stress annealing, the iron-based amorphous alloy and application. The method comprises the steps that periodic stress is applied to the iron-based amorphous alloy, and periodic strain is generated; the peak strain of the periodic strain is less than or equal to 2%, and the valley strain of the periodic strain is lower than the peak strain. Appropriate periodic stress is applied to the iron-based amorphous alloy at the low temperature, periodic strain is generated, the negative influence of rapid cooling on the soft magnetic performance during preparation of the iron-based amorphous alloy in the prior art can be improved, the brittleness problem generated by high-temperature annealing can be avoided, the soft magnetic performance and brittleness are better balanced, and the service life of the iron-based amorphous alloy is prolonged. And the effect of coexistence of ultralow coercive force and good toughness is achieved.

The invention belongs to the field of material mechanical property testing and strain measurement, and particularly relates to a local strain measurement method and system based on a four-point bending and digital image correlation (DIC) technology, and the method specifically comprises the following steps: cutting to prepare a sample, carrying out surface electrolytic polishing, preparing speckles on the surface of the sample to be tested, and carrying out a four-point bending experiment; speckle images of the lower surface of the sample are collected, displacement correction is conducted in combination with bending deflection calculation, the bending load and the strain of the upper surface of the sample are obtained in real time, the stress-strain relation and local strain distribution of the lower surface of the sample are obtained through calculation, and finally deformation and failure mechanism analysis is conducted in combination with surface deformation and crack morphology. The method provided by the invention combines four-point bending and DIC plane strain measurement technologies, can realize stretching, compression and dynamic fatigue loading on the surface of the sample, is suitable for performance test and failure analysis of tension, compression and fatigue deformation of brittle metal materials such as intermetallic compounds and amorphous materials, and has the characteristics of convenience, rapidness and low cost.

Aspect of the disclosure provides a method of pumping a liquid material. The method may include pumping the liquid material by rotating an impeller attached to a shaft assembly. The pump includes the impeller, the shaft assembly, and a pump chamber. The method includes controlling the minimum pressure of the liquid material in the pump chamber to be above a threshold pressure by controlling a pressure of a gas that is supplied to the pump chamber. The shaft assembly includes a first shaft and a second shaft that are separated by a gap and are physically coupled by a coupling component.

The invention belongs to the technical field of metal composite materials and hydrogen storage and transportation materials, and particularly relates to a high-strength hydrogen-embrittlement-resistant layered metal composite material for hydrogen storage and a preparation method and application of the high-strength hydrogen-embrittlement-resistant layered metal composite material. According to the preparation method, the nickel-saving austenitic stainless steel (NEASS) and the 30CrMo steel are alternately overlapped in a multi-layer mode, and the processes of vacuum electron beam welding, high-temperature hot rolling, accumulative ply rolling, multi-stage heat treatment and the like are combined, so that the composite board with the layer number reaching hundreds of layers, firm interface bonding, excellent mechanical performance and good hydrogen embrittlement resistance is prepared; the technical problem that strength, toughness and hydrogen brittleness resistance of an existing metal material in a high-pressure hydrogen environment are difficult to consider at the same time is solved. The obtained composite material has high strength, high plasticity and excellent hydrogen embrittlement resistance, and is suitable for structural materials of high-pressure hydrogen storage tanks, hydrogen conveying pipelines and other key hydrogen energy equipment.

The invention discloses a deep tunnel surrounding rock mechanical parameter inversion method based on a three-dimensional brittle failure zone contour and sparrow optimization algorithm-information vector machine (SSA-IVM) combined optimization algorithm. The engineering technical problem that due to the fact that excavation instantaneous displacement is difficult to monitor, deep tunnel surrounding rock mechanical parameters are difficult to reasonably obtain through displacement back analysis is solved. The method comprises the following steps: firstly, constructing a tunnel FLAC3D numerical simulation model with the same ground stress condition at the occurrence position of a three-dimensional brittle failure zone; secondly, taking an absolute error between the total number of computational grid units in the actually measured brittle failure zone and the total number of computational grid units entering a plastic state in the range of the actually measured brittle failure zone after calculation of the FLAC3D numerical model as an optimization objective function; and then, by taking the tunnel surrounding rock mechanical parameters as optimization variables and taking a target function reaching a global minimum value as a target, performing global optimization by combining a tunnel FLAC3D numerical model and adopting an SSA-IVM joint optimization algorithm, thereby obtaining reasonable tunnel surrounding rock mechanical parameters.

A preparation and use method for an Nb5Si3 composite spheroidized powder. The preparation method comprises: A) mixing an Nb powder, an Si powder, PVA and water, and ball milling the resulting mixture to obtain a slurry; and subjecting the slurry to spray granulation and sieving, so as to obtain an Nb5Si3 composite agglomerated powder; and B) subjecting the Nb5Si3 composite agglomerated powder to plasma spheroidization to obtain the product. The use method comprises mixing the Nb5Si3 composite spheroidized powder with NbTiX, wherein X is three or more of Zr, Hf, V, Mo and Ta; Nb and Si in the raw materials are subjected to an in-situ reaction during a laser additive melting process; and in combination with a rapid solidification process, a submicron Nb5Si3 particle-reinforced Nb5Si3 / Nbss dual-phase alloy can be obtained. Compared with a cast alloy having the same components, the Nb5Si3 particle-reinforced phase can be greatly reduced from a size level of dozens of microns to a submicron level, which greatly reduces the brittleness of the particle-reinforced refractory alloy, and significantly improves the strength of the particle-reinforced refractory alloy.

The invention relates to the technical field of ceramics, and provides an environment-friendly ceramic containing bamboo fiber and a preparation method thereof, the environment-friendly ceramic containing bamboo fiber comprises the following raw materials by mass: 50-60 parts of kaolin, 18-28 parts of quartz sand, 10-16 parts of feldspar powder, 22-36 parts of modified bamboo charcoal fiber, 0.5-1 part of a binder and 0.2-0.6 part of a dispersant. Wherein the bamboo charcoal fiber is used as a raw material and is environment-friendly and biodegradable; the bamboo charcoal fiber modified by alkali treatment and a sol-gel method has better compatibility with a ceramic matrix and is uniformly dispersed, and the agglomeration phenomenon is reduced, so that the impact resistance and toughness of the ceramic are improved, and the defect of high brittleness of the traditional ceramic is overcome; the honeycomb microporous structure of the bamboo charcoal fiber endows the ceramic with the functions of adsorbing harmful substances, resisting bacteria and deodorizing, so that the ceramic prepared by the invention has excellent antibacterial, deodorizing and mechanical properties, is environment-friendly, and has important application value in the fields of sanitary ware, tableware and the like with high sanitary requirements.

The invention discloses an annular furnace heat-resistant supporting forged chassis and an additive manufacturing process and a fixing device thereof, and belongs to the technical field of plating of metal materials, and the annular furnace heat-resistant supporting forged chassis comprises the steps that heat-resistant alloy steel base metal with specific components is prepared; carrying out laser texturing and nickel-based alloy bottom layer pretreatment on the surface of the steel plate; performing laser cladding on high-silicon high-temperature alloy powder containing niobium and rare earth elements to form a functional cladding layer, and performing gradient cladding on the edge of the atmosphere guide hole; and finally, carrying out heat treatment and assembling with a fan-shaped refractory brick fixing device. A composite oxide film and a multi-scale strengthening system are constructed, hydrogen resistance and brittleness resistance are effectively achieved, interface thermal stress is relieved, cracking and stripping of a cladding layer are avoided, a fixing device adapts to thermal expansion, the atmosphere is dredged, and the annealing uniformity of a steel coil is improved; the problems of creep deformation, hydrogen embrittlement, cladding layer stripping and thermal stress cracking of a traditional supporting component under the conditions of high temperature, heavy load and nitrogen and hydrogen atmosphere are solved.

The invention discloses a fragile material crack detection and damage evaluation method based on box dimension. Change information of a material surface displacement field is calculated by adopting a DIC technology (a digital image correlation technology), a main strain graph is obtained, then the box dimension of the material surface main strain field is calculated by combining a fractal theory, and the damage degree of the material is quantified based on change development of the box dimension. According to the invention, the development process of the cracks of the material test piece from no to penetrating through the test piece can be observed, the crack growth path can be obtained, the crack development can be quantified through the specific box dimension, the damage degree of the structure can be evaluated, and the early warning of the large crack propagation behavior is realized. The method has important practical engineering significance for health detection and risk assessment of fragile material structures such as steel fiber reinforced concrete.

The invention belongs to the technical field of steel forging, and particularly relates to martensite heat-resistant steel and a forging method. A forging process is optimized and improved, and after forging, furnace cooling of a forge piece is changed into the mode that the forge piece is rapidly cooled in air to 30-50 DEG C above the Ms transition point firstly, and then the forge piece is put into a furnace to be cooled along with the furnace. And coarse carbides generated during slow cooling of the material in a high-temperature area are avoided, then the material is put into a furnace to be cooled along with the furnace, and the forge piece is prevented from cracking during rapid cooling at the Ms point and below the Ms point. In the forge piece heat treatment process, the quenching charging mode is changed from furnace heating to temperature charging, the forge piece heating rate is increased, the superheat degree in the material austenitizing process is increased, the nucleation rate is promoted to be increased, and the grain size of the quenched forge piece is effectively increased. And the second tempering cooling mode is changed from air cooling to oil cooling. And the generation of second-class tempering brittleness in the tempering process is effectively avoided. A plurality of batches of forgings are produced according to the optimized process scheme, the impact performance tends to be stable, and the situation that the accidental impact performance is unqualified does not occur any more.

The invention discloses a composite high-temperature wear-resistant gradient coating special for a titanium alloy knife edge. The composite high-temperature wear-resistant gradient coating comprises a Ni-Ti transition coating, a Co-based alloy coating and a Co-based ceramic composite wear-resistant coating which are sequentially arranged on the surface of the titanium alloy knife edge in a laser cladding mode. The preparation method comprises the following steps: 1, polishing and cleaning a titanium alloy knife edge; 2, Co-based ceramic composite wear-resistant coating powder is prepared; 3, drying the raw material powder; and fourthly, the dried powder serves as raw materials, and laser cladding of a Ni-Ti transition coating, a Co-based alloy coating and a Co-based ceramic composite wear-resistant coating is sequentially conducted on the treated titanium alloy knife edge. By controlling the gradient change of the contents of Ti and Ni elements in the Ni-Ti transition coating, Ti and Co elements are prevented from being combined to form a brittle phase, the cracking sensitivity of the Co-based alloy coating is reduced, and falling is prevented; according to the laser cladding method, the heat input amount is controllable, and the bonding strength of the coating and the titanium alloy knife edge base body is improved.

The invention relates to the technical field of stainless steel production and manufacturing, and discloses a high-strength corrosion-resistant duplex stainless steel shaft forging method which comprises the steps of blank preparation, homogenization treatment, preheating treatment, multidirectional forging, interrupted cooling, solution treatment, aging treatment and surface finish machining. Uniformity of components in the blank and consistency of temperature distribution are guaranteed, a uniform microstructure basis is provided for subsequent forging, meanwhile, grains are refined through large deformation and multi-pass deformation in multi-directional forging, the strength and toughness of the shaft are improved, brittle phase formation is avoided, and the mechanical property is optimized; by interrupting cooling and solution treatment, controlling the cooling rate and heating parameters in real time, inhibiting harmful phase precipitation and optimizing the austenite-ferrite phase proportion, the shaft has high corrosion resistance, and by means of aging treatment, through a stable structure, the long-term durability of the shaft in a severe environment is guaranteed, and the corrosion weight loss and pitting corrosion risk are reduced.

The invention relates to a multi-component composite modified geopolymer material and a preparation method thereof, and aims to solve the problems of high brittleness, easiness in cracking and poor durability of a traditional geopolymer. According to the material, industrial solid wastes (carbonized steel slag, volcanic ash and the like) are used as main matrixes, a macroscopic anti-cracking framework is constructed through red copper fibers, micropores are nanofilled with CVD silicon oxide substrate graphene, and polyamide resin flexibly buffers stress, so that a cross-scale reinforcing system is formed. The preparation method adopts a solid phase premixing-liquid phase excitation-gradient compounding process, and functional components are doped in sections, so that the dispersity and constructability are guaranteed. The technical effects are obvious: the breaking strength is reached, the splitting tensile strength is obviously improved, the mass loss rate is obviously reduced after freezing and thawing for 100 times, and the shrinkage crack self-limit is within 50 [mu] m. The carbon emission of the material is greatly reduced, the high-durability standard is met, and the material is suitable for severe environmental engineering.

The invention provides a hot forming method of a zinc-based coated steel plate, the coated steel plate, a hot forming part and a hot forming system. According to the hot forming method of the zinc-based coated steel plate, cracking caused by brittleness of liquid metal on the surface of the coated steel plate is prevented through the uniform controlled cooling effect of the high-temperature spraying medium, and when the temperature of the steel plate is reduced, cracking caused by the brittleness of the liquid metal can be prevented; and the formed hot forming part is good in surface quality, the defects of piebald and chromatic aberration caused by non-uniform cooling are avoided, high-strength parts within the range of 500-2000 MPa can be formed, the strength of the formed steel plate is guaranteed, and the brittleness problem of liquid metal can be prevented.

The invention belongs to the technical field of optical glass, and discloses an optical glass structure with a high-hardness scratch-resistant coating, which comprises the following structures: a chemically strengthened glass substrate; the refractive index gradient transition layer is deposited on the surface of the substrate; and the diamond-like carbon-based hard coating covers the surface of the transition layer. The defect is thoroughly overcome through a gradient strengthening system, the diamond-like carbon coating resists invasion of external abrasion particles through a crystal bonding network close to absolute hardness, so that the surface microhardness breaks through the upper limit of a brittle material, the gradient transition layer constructs an elastic buffer strip below the coating, impact stress is dissipated through the porous nano laminated layer, and the hardness of the coating is improved. The cooperation of the two ensures that no visible scratch is generated on the glass surface even if the glass surface is exposed to a high-wear environment for a long time, thereby fundamentally blocking linkage failures such as light path scattering, imaging blurring and dispersion imbalance caused by surface damage, and ensuring that the light transmittance of a precise optical system in the whole life cycle is stabilized at a theoretical extreme value.

The invention discloses a material with a silver coating for low-temperature brazing of brazing filler metal, and particularly relates to the field of brazing welding, which comprises the following steps: silver amalgam paste is prepared by oscillating and mixing silver powder and mercury according to the mass ratio of 1: 9-0.5: 9.5 in a manner and method for plating silver on the surface of base metal (metal, semiconductor, ceramic or glass); when brazing is carried out, the surface of the silver plating layer of the to-be-welded piece is coated with brazing filler metal, and then heating and pressurizing are carried out in a low-temperature interval of 120-350 DEG C in a vacuum, protective atmosphere or atmospheric environment to complete connection. According to the method, the amalgam reaction and isothermal solidification principles are utilized, a tough welding spot mainly comprising a silver-based solid solution is finally formed, generation of a large number of brittle intermetallic compounds is avoided, a connector has high strength, high reliability and excellent thermal fatigue resistance, and therefore the problems that gold-tin brazing filler metal is high in cost, the brittleness of the welding spot is large, and the welding temperature is high are successfully solved.

The invention discloses a device for manufacturing a progressive interface of a heterogeneous material and a control method, and relates to the technical field of laser additive manufacturing. The mixing uniformity of components in a heterogeneous material transition region is remarkably improved, and the size and distribution uniformity of grains and a brittle second phase in a heterogeneous interface transition region are reduced, so that the mechanical property of a heterogeneous material connection region is remarkably improved. And meanwhile, the double-barrel powder feeder and the spiral powder mixing stirrer are adopted, uneven mixing caused by large density difference of heterogeneous materials is avoided, online real-time adjustment and conveying of the metal powder in the progressive mixing proportion can be achieved, and cracking caused by interface component mutation due to component gradient step length of the mixed powder is avoided. On the basis, progressive transition of titanium alloy-transition interface-aluminum alloy components is formed, effective connection of heterogeneous materials with large physical property parameter differences is achieved, and then integrated composite forming of the heterogeneous alloy and large complex structural parts can be achieved.

The invention provides a brittle material cyclic loading and unloading test simulation method based on discrete elements. The method comprises the steps that a cyclic loading and unloading constitutive model used for describing the mechanical state of particles when a brittle material is affected by cyclic loading is constructed; based on a discrete element method and a cyclic loading and unloading constitutive model, inputting parameters and conditions, and if the time step length is not reached, calculating particle stress information; if the time step length is reached, directly outputting a calculation result and drawing a cloud picture; traversing all the particles, calculating the speed and displacement of the particles according to the stress information of the particles, outputting a calculation result, and drawing a cloud picture. According to the invention, reference can be provided for mechanical characteristics of cyclic loading and unloading tests of the fragile material, cyclic loading, fatigue and plastic failure of the fragile material under the cyclic loading condition can be reflected, and production safety in the construction process can be guaranteed; the technical problem that an existing cyclic loading and unloading test simulation method depends on experience judgment of linear regression and cannot meet the scene requirements of a nonlinear relation and plastic failure is solved.

The invention relates to a laser cutting method and system based on brittle materials and an intelligent terminal, and relates to the technical field of laser cutting. The cutting thickness is determined according to the manufacturing specification; when the cutting thickness exceeds the reference thickness, a cutting path is determined according to the manufacturing specification and the cutting specification; determining the beam splitting number and marking the beam splitting specification according to the manufacturing specification and the preset beam splitting specification, and controlling the laser beam spatial light modulator to operate according to the beam splitting number; according to the beam splitting number, marking beam splitting specifications and a beam splitting arrangement method to determine focusing parameters, and controlling a laser beam spatial light modulator to operate; determining output power according to the focusing parameter and the manufacturing specification, and controlling the laser device to perform laser cutting according to the cutting path and the output power; and after cutting is completed based on the laser device, a preset knocking device is controlled to conduct knocking according to the cutting path. The laser cutting device has the effect of improving the laser cutting efficiency of the brittle material.

The invention belongs to the technical field of brazing materials, and discloses high-entropy composite brazing filler metal and a preparation method and application thereof. The high-entropy composite brazing filler metal comprises a nickel-based brazing filler metal matrix and high-entropy alloy powder, and the high-entropy alloy powder comprises, by atomic percent, 15%-25% of Co, 15%-25% of Cr, 15%-25% of Fe and 25%-45% of Ni. According to the high-entropy composite brazing filler metal, the low melting temperature is kept, the high-entropy alloy particles can adjust joint residual stress caused by the large difference of thermal expansion coefficients of dissimilar materials, the interface regulation and control effect is achieved, generation and distribution of joint brittle phases are affected, a special core-shell structure is formed around the high-entropy particles, and therefore the high-entropy composite brazing filler metal can be obtained. A continuous brittle phase formed by a joint can be broken, crack propagation is prevented, the mechanical property of the joint is remarkably improved, the brazing filler metal preparation method is simple and easy to implement, and the high-entropy composite brazing filler metal adopts an instantaneous liquid diffusion brazing mode, so that weld joint structure components are homogenized.

An aluminum nitride ceramic welding assembly comprises a first aluminum nitride ceramic piece, a second aluminum nitride ceramic piece and a third aluminum nitride ceramic piece, a second pin hole corresponding to the first pin hole is formed in the welding surface of the second aluminum nitride ceramic piece; two ends of the aluminum nitride ceramic positioning pin are respectively inserted into the first pin hole and the second pin hole; and the slurry layer containing rare earth oxide is arranged on the welding surface of the first aluminum nitride ceramic piece, and the distribution density of the rare earth oxide is gradually reduced from the position close to the first aluminum nitride ceramic piece to the position far away from the first aluminum nitride ceramic piece. High-temperature displacement errors are eliminated by means of cooperative positioning of pin holes in the first aluminum nitride ceramic piece and the second aluminum nitride ceramic piece and aluminum nitride ceramic positioning pins; and meanwhile, generation of brittle phases is inhibited by utilizing a form that the distribution density of rare earth oxides in the slurry layer is gradually reduced from near to far, so that the effects of a high-precision welding interface and joint strength enhancement are obtained, and the reliability and the service life of the aluminum nitride ceramic component are improved.

The invention discloses a construction method of an assembly type prefabricated steel pipe-pipe pile composite high-strength toughness stand column pile, and belongs to the field of foundation pit supporting. According to the stand column pile construction method, an adopted stand column pile comprises a foundation pile section, a bottom plate section, a stand column section and a supporting section, the construction method comprises the steps of foundation pile section construction, bottom plate section construction, stand column section and supporting section construction, foundation pit excavation and supporting construction and foundation pit bottom plate and main body structure construction, and the foundation pile section is a prefabricated pipe pile; by improving the steel-concrete composite structure of the prefabricated steel pipe pile, the strength and toughness of the pile body of the stand column pile are improved, the structural strength of the stand column section is improved, brittle failure of the stand column pile in the construction process is avoided, holding and pressing construction can be conducted through a static pressure pile machine, and the optimal design of the construction sequence is matched. The construction efficiency of the stand column pile is greatly improved; moreover, the stand column section is assembled by adopting a socket structure, so that 100% recycling can be realized, the construction cost is reduced, and the economical efficiency of the stand column pile is remarkably improved.

The invention discloses a manufacturing process of a 1J22 alloy bar with high mechanical performance and high magnetic performance, and belongs to the technical field of precision alloy material processing, the process comprises a rapid cooling treatment step, in the cooling stage after forging or hot rolling forming of the bar, the bar is cooled to be below 650 DEG C from the high temperature not lower than 900 DEG C at the cooling speed of at least 320 DEG C / h, and then the bar is cooled to be below 650 DEG C at the cooling speed of at least 320 DEG C / h; as a 1J22 bar has ordered-disordered transformation at 730 DEG C, in order to prevent brittleness after ordering at 730 DEG C, the bar needs to be quickly cooled within a specific temperature range to improve the brittleness of the material. Compared with the prior art, the 1J22 alloy bar produced on the basis of the technology can guarantee that the magnetic performance is superior to the national standard GB / T14986.3-2018, meanwhile, the mechanical performance is improved, the brittleness is improved, and the phenomena of tooth collapse, corner falling and cracking occurring in the machining process are reduced.