1500 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 low-temperature rolled high-quality free-cutting steel and a production process thereof. The low-temperature rolled high-quality free-cutting steel comprises the following components: less than or equal to 0.10% of C, less than or equal to 0.006% of Si, 0.90-1.60% of Mn, 0.30-0.90% of P, 0.30-0.50% of S, less than or equal to 0.030% of Al, less than or equal to 0.0060% of N, less than or equal to 0.0140% of O and the balance of Fe and other inevitable impurities. Compared with the prior art, by controlling Mn / S to be 3.5-7.0, when the K value is equal to 2 * (Mn / S) + LF activity oxygen value, and K is larger than or equal to 35 and smaller than or equal to 69, the final sulfide is properly controlled. Low-temperature rolling is adopted, the sulfide hot brittleness interval is avoided, the plasticity of sulfide is relatively poor during rolling in the temperature interval, energy consumption is reduced, and meanwhile the phenomenon that the cutting performance of a finished product becomes poor due to the fact that the sulfide is lengthened in the rolling process is avoided. Finally, the high-quality free-cutting steel production process adopting low-temperature rolling is developed.

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 welding material, a welding material, application and a preparation method, and the welding material comprises the following raw materials by weight percent: 1%-3% of Si, 1.2%-3.2% of Mg, 1%-3.6% of Zn, 0.6%-1.6% of Cu, 0.5%-0.8% of Mn, 0.2%-0.45% of Cr, 0.1%-0.25% of Ti, 0.05%-0.1% of Zr, 0.05%-0.1% of Sc, and the balance of Fe. 0.2%, and the balance being Al and inevitable impurities. By regulating and controlling the contents of Zn, Cu, Mg and Si elements, the precipitation enthalpy of a nanoscale strengthening phase is reduced, so that the bake hardening effect of a welding seam is improved, and the problem that the welding seam is excessively softened due to melting of the nanoscale precipitation phase is solved. In addition, the Fe-containing brittle phase characteristic in the weld joint is improved by adding Mn and Cr elements, and the hot crack tendency of the weld joint is reduced by combining Zr, Sc, Ti and other grain refinement elements, so that the strength and toughness of the weld joint are further improved.

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 aluminum plate machining, and particularly relates to an aluminum plate longitudinal cutting device which comprises a supporting table, and a discharging roller and a collecting roller are arranged at the top of the supporting table. By arranging the induction coil, the first permanent magnet, the second permanent magnet and the electromagnetic heating plate, the aluminum plate which is not longitudinally cut is heated, the hardness and brittleness of the aluminum plate can be reduced, longitudinal cutting is smoother, the quality of finished products is improved, deformation of the aluminum plate is reduced during longitudinal cutting, and the cutting precision and stability are ensured; by arranging a fixing plate, a shaking plate, piezoelectric ceramic pieces, springs and the like, the two piezoelectric ceramic pieces are placed in a cutting gap of an aluminum plate, when a longitudinal cutter is abraded, the cutting gap can be enlarged, the shaking amplitude of the piezoelectric ceramic pieces in the cutting gap is increased under pushing of the first spring, output current is increased, and the cutting effect of the aluminum plate is improved. And the state of the longitudinal cutter can be conveniently monitored in real time for subsequent detection operation.

The invention relates to the technical field of high-chromium and high-molybdenum ferritic stainless steel, in particular to a preparation method of a high-chromium and high-molybdenum aluminum-containing ferritic stainless steel hot / cold-rolled plate. In order to solve the problems that in the prior art, in order to avoid brittle phase precipitation, the hot rolling and finish rolling temperature is high, and aluminum oxide particles and large-size carbon / nitride particles are likely to be formed, the novel preparation method of the high-chromium and high-molybdenum aluminum-containing ferrite stainless steel hot / cold-rolled sheet is provided. Comprising the following steps of smelting, casting, forging, hot rolling, annealing, acid pickling, cold rolling and recrystallization annealing, and through the forging process in the preparation method, large-size TiN and Ti / Nb (C, N) particles can be prevented from being formed; through the warm rolling process, a nanoscale Laves phase is separated out, meanwhile, a large deformation structure is formed, a large number of deformation microstructures such as shear bands and deformation bands are obtained, the problem of grain coarsening is solved, and the plasticity, toughness and corrosion resistance of the material are improved.

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.

The invention provides special-shaped copper pipe machining equipment for a copper-aluminum composite bar and a machining method of the special-shaped copper pipe machining equipment, and relates to the technical field of copper pipe rolling machining. The special-shaped copper pipe machining equipment for the copper-aluminum composite bar comprises a machine tool, and a rolling device, a driving device, a flame jetting device and a straightening device are arranged on the upper surface of the machine tool. According to the special-shaped copper pipe processing equipment for the copper-aluminum composite bar, the fire spraying assembly is arranged in the copper pipe for continuous heating to prevent temperature loss, and the lining assembly is matched to abut against the heated inner wall, so that the problem that uncontrollable pits, protrusions and falling metal impurities are generated on the inner wall in the rolling process due to the fact that the inner wall of the copper pipe is lack of supporting is solved; and the problem of slipping or rigid fracture in the compression process due to temperature loss when the steel sheet enters a medium-temperature brittle zone is prevented.

The invention relates to a weakening-free polyurethane composite material as well as a preparation method and application thereof. The weakening-free polyurethane composite material comprises a polyurethane surface layer, a polyurethane high-solid bonding layer and a base cloth layer which are sequentially arranged from top to bottom, wherein the polyurethane high-solid bonding layer is prepared from a polyurethane high-solid bonding layer slurry, and the polyurethane high-solid bonding layer slurry is prepared from the following components in parts by mass: 100 parts of a reactive polyurethane prepolymer, 5 to 10 parts of a cross-linking agent, 20 to 50 parts of a filler and 5 to 10 parts of color paste. According to the polyurethane high-solid bonding layer disclosed by the invention, the reaction type polyurethane prepolymer, the cross-linking agent and the filler react according to a certain proportion to form a three-dimensional network cross-linked structure, so that a leather film has certain strength and brittleness, and the weakening-free polyurethane composite material can generate overall brittle fracture under the impact of ignition force; and safe unfolding of the air bag is ensured.

The invention relates to high-strength microcrystalline glass and a preparation method thereof, and belongs to the technical field of composite materials. The high-strength glass ceramic is prepared from cullet, titanium dioxide, spodumene, potassium carbonate, lanthanum oxide, boron nitride, barium oxide, zirconium oxide and modified carbon fibers as raw materials, and the invention further discloses a formula of the raw materials. According to the high-strength glass ceramic, the modified carbon fibers serve as a reinforcing phase, the problem that the glass ceramic has brittleness and is prone to breakage is solved, the modified carbon fibers and a glass ceramic base material are good in phase property, and therefore the prepared glass ceramic is excellent in mechanical performance, the highest impact toughness can reach 3.91 KJ / cm < 3 >, the highest compressive strength can reach 371.28 MPa, and the glass ceramic can be used as a high-strength glass ceramic. The breaking strength can reach 46.93 MPa to the maximum, and in addition, the modified carbon fiber can also improve the thermal stability of the microcrystalline glass and solve the yield influence caused by thermal stress.

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.

A glass and metal laser welding method using a double-layer structure solder and its solder, the method includes: surface pretreatment, ultrasonic cleaning of the metal and glass surfaces, using pulsed laser deposition technology to sequentially deposit nano-Si and Al double-layer thin film pre-solder in the area to be welded on the glass surface; assembly, assembling the glass and metal according to the requirements of the connection joint, placing the glass solder with the pre-solder downward on the metal, and clamping the two with a clamp; nanosecond laser welding, focusing the laser on the contact surface of the thin film solder and the glass, and keeping the focus on the same plane, turning on the laser to scan and weld on the focal plane; post-welding treatment, using high-frequency nanosecond laser for post-welding heat treatment, and naturally cooling the joint after treatment. The present invention can accurately control the thermal effect generated in the tiny welding area, improve the wettability between the glass and metal interface, inhibit interface brittle compounds, and reduce thermal stress and residual stress.

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 relates to preparation of a tungsten-containing stainless steel gradient material. The method mainly comprises the following steps: obtaining mixed powder which is composed of 316L stainless steel powder and tungsten powder and has a plurality of different weight ratios, and applying the mixed powder to a forming substrate layer by layer according to a gradient change sequence to form powder layers, and controlling a laser beam to perform selective melting matched with the process parameters on the powder layer along a preset scanning path so as to form a consolidated gradient material part. Smooth change of the density gradient is achieved by adjusting the tungsten content, formation of cracks and brittle compounds in a traditional printing technology is avoided, the density of the gradient material can be accurately adjusted and controlled within a wider range, and the method is particularly suitable for the application field with the requirement for high density and the complex internal structure.

The invention relates to the technical field of round steel heat treatment, and discloses a round steel integral quenching and tempering heat treatment method which comprises the following specific steps: S1, preparing materials; s2, equipment inspection; s3, a tool clamp is prepared; s4, charging; s5, heating; s6, quenching; s7, discharging and cooling; according to the overall quenching and tempering heat treatment method for the round steel, the comprehensive mechanical performance of the round steel is improved, the surface of the round steel obtains a high-hardness martensitic structure by accurately controlling the quenching heating temperature, the heat preservation time and the cooling speed, meanwhile, a core part keeps certain toughness, and therefore the strength and toughness of the round steel are improved; through the reasonable high-temperature tempering process, quenched martensite is fully decomposed and converted, a tempered sorbite structure is formed, the plasticity and toughness of the round steel are improved, the brittleness of the round steel is reduced, the round steel has good comprehensive mechanical performance, and according to the scheme, the production efficiency and the product quality stability are improved, process parameter control is accurate, and equipment operation is stable; and waste products and inferior-quality products caused by process fluctuation are reduced.

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 discloses a thermal-mechanical coupling near-field dynamics simulation method and system for thermal cracking of a brittle material, a medium and equipment, and belongs to the technical field of material and structure damage simulation, and the method comprises the following steps: S1, building a solid model, inputting basic information, discretizing the model, building a near-field dynamics material point position matrix and key connection information, and establishing a near-field dynamics model; assembling a near-field dynamic matrix; s2, initial conditions and boundary conditions are set, and an explicit staggered solution method is adopted to iteratively solve the temperature field and the displacement field of the near-field dynamic matrix step by step in sequence; and S3, drawing a temperature field, a displacement field and a result cloud chart of damage according to the solved data. According to the method, the heterogeneous characteristics of the brittle materials are considered, the thermal-mechanical coupling model is established based on the near-field dynamics theory, the adopted coupling model conforms to engineering practice, and simulation and prediction of the cracking problem of the multiple brittle materials under the temperature load effect can be stably and accurately achieved.

The invention relates to the technical field of heat insulation materials, in particular to a ceramic aerogel coating and a preparation method thereof.The ceramic aerogel coating comprises a ceramic anti-corrosion bottom layer, a middle coating and a transparent surface layer, and the preparation method of the ceramic aerogel coating comprises the steps that firstly, sand blasting treatment is conducted on a metal base material; step II, spraying a ceramic anti-corrosion primer, and drying; iII, preparing a floating coat base material; iV, spraying a floating coat base material, and sealing and baking; v, spraying a floating coat fabric, and sealing and baking; step VI, polishing the coating; step VII, spraying transparent finish paint after polishing, and sealing and drying; and step VIII, after unified inspection is completed, finish paint is sprayed, sealing baking is conducted for thorough drying, and then the ceramic aerogel coating is obtained, the prepared ceramic aerogel coating is good in adhesiveness, excellent in acid and alkali resistance, not prone to cracking and peeling, capable of protecting metal for a long time, low in heat conductivity coefficient and high in hardness, and the problems that an existing aerogel coating is high in brittleness, weather resistance and hardness and not prone to cracking and peeling are solved. And the mechanical performance is low.

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 present invention relates to the a coating and the preparation thereof for improving glass strength and fracture toughness comprising the hydrolytic polycondensation product of one or more alkoxysilane(s) with one or more metal oxide(s) and / or metal alkoxide(s) in the presence of water and a catalyst. The present invention also relates to the use of the coating for repairing damaged silica containing materials.