98 results about "Single crystal superalloy" patented technology

The invention discloses a nickel-based single-crystal high-temperature alloy with high structure stability and a preparation method thereof, and relates to the technical field of high-temperature alloys. The nickel-based single crystal high-temperature alloy provided by the invention is prepared from the following components in percentage by mass: 5 to 7 percent of Al, 7.5 to 10 percent of Co, 5 to 7 percent of Cr, 0.1 to 0.2 percent of Hf, 0 to 2 percent of Mo, 5.5 to 7.5 percent of Ta, 0 to 1 percent of Ti, 8 to 10 percent of W, 0.02 to 0.05 percent of C, 0.003 to 0.005 percent of B and the balance of Ni. According to the invention, by controlling the ratio of elements and avoiding the addition of Re, the precipitation temperature of a harmful TCP phase is obviously reduced to about 840 DEG C on the basis of maintaining a sufficient solid solution strengthening effect, and the long-term stability of the structure is greatly improved. The high-temperature mechanical property of the alloy provided by the invention reaches the level equivalent to that of a traditional Re-containing second-generation single-crystal alloy and is remarkably superior to that of foreign Re-free single-crystal alloys MD2 and Rene N500, and the nickel-based single-crystal high-temperature alloy with high structure stability successfully realizes the unification of low cost and high performance, and is suitable for industrial production. And a reliable material solution is provided for manufacturing the heavy-duty gas turbine blade with higher market competitiveness.

The present application relates to single crystal superalloy blade recrystallization detection technical field, disclose a kind of single crystal superalloy blade recrystallization detection method, device and equipment, the method includes: constructing single crystal superalloy recrystallization database;The single crystal superalloy creep sample containing recrystallization is subjected to creep test to obtain corresponding single crystal superalloy and corresponding blade under corresponding service condition recrystallization damage tolerance;The coordinate information of the deformed position of the single crystal superalloy blade to be detected is obtained;Corresponding parameters are input into database to obtain the cross-sectional recrystallization area fraction and maximum recrystallization depth of the deformed position of the single crystal superalloy blade;Whether the cross-sectional recrystallization area fraction and maximum recrystallization depth of the deformed position obtained are less than the corresponding recrystallization damage tolerance is judged to obtain detection result.The detection accuracy is high, the yield is improved, and the production quality acceptance standard of single crystal superalloy blade or test bar, nondestructive testing is expanded to provide reference.

The invention discloses a method and a device for predicting creep deformation of a nickel-based single-crystal high-temperature alloy under creep-oxidation interaction, and belongs to the technical field of material engineering and computational mechanics, and the method is based on microstructure distribution characteristics of the nickel-based single-crystal high-temperature alloy after a creep test in vacuum and atmospheric environments. According to the method, a dynamic growth multilayer geometric model considering oxidation influence is established, and a method capable of predicting alloy creep deformation in different environments is developed by combining a creep constitutive model considering microstructure evolution based on a test observation result. The method mainly comprises the following steps: providing a multilayer geometric model considering oxidation influence; establishing growth kinetic models of different layers; obtaining microstructure evolution laws at different depths; building a multi-scale creep deformation prediction framework considering microstructure evolution; and acquiring model parameters and predicting creep deformation. The invention provides a set of method capable of accurately predicting the creep deformation of the alloy in different environments.

The invention discloses a single-crystal high-temperature alloy and ceramic matrix composite material-based functional partition type composite blade design method, which comprises the following steps of defining a temperature bearing area and a force bearing area of a blade through heat and force simulation; the brazing residual stress is predicted, and the optimal assembly gap between the two partition interfaces of the temperature bearing area and the force bearing area of the composite blade is optimized and determined; predicting peak stress, and optimizing and determining the optimal position and size of a mechanical locking structure between two partition interfaces of a temperature bearing area and a force bearing area of the composite blade; and through heat-force-flow coupling simulation, the maximum equivalent stress of the composite blade and the bonding strength between partition interfaces are evaluated, and then the design of the composite blade is completed. According to the method, through heat-force-flow coupling simulation and iterative optimization, precise definition of function partitions and cooperative compatibility of mechanical locking and the process are achieved, and the low-stress and high-strength performance of the composite blade in the high-temperature and high-pressure environment is ensured.

The invention discloses a method for avoiding solidification defect formation in a single crystal blade preparation process caused by seed crystal oxidation, and belongs to the technical field of single crystal high-temperature alloy blade preparation. According to the method, by quantitatively detecting the thickness of an oxide layer at the top end of a seed crystal and establishing a mathematical quantitative corresponding relation between the thickness and the heat preservation time of a mother alloy after pouring, a heat preservation process is dynamically regulated and controlled, the oxide layer is fully decomposed or broken, and formation of defects such as mixed crystals and small-angle grain boundaries is effectively inhibited; and meanwhile, the height of the formwork expansion area is synchronously optimized according to the needed heat preservation time, and the macrosegregation problem caused by long-time heat preservation is avoided. Quantification and precision of seed crystal oxidation control are achieved for the first time, the preparation success rate and structure consistency of the single crystal blade are remarkably improved, and the method has the outstanding advantages of being high in process feasibility, low in production cost, wide in application range and the like.

The invention relates to the technical field of heat treatment of single-crystal castings, and aims to solve the problem that in the production process of single-crystal high-temperature alloy castings, solid solution heat treatment can cause recrystallization of materials, and the problems that existing countermeasures are difficult to effectively solve or can not be effectively solved under the condition that the performance of the materials is not affected. The method for inhibiting recrystallization in the solid solution heat treatment process of the single-crystal high-temperature alloy casting sequentially comprises the steps of S1, pretreatment, S2, recovery heat treatment and S3, solid solution heat treatment. The recovery heat treatment comprises at least one heat treatment cycle, each heat treatment cycle comprises vacuum heat treatment t1, static inert gas partial pressure heat treatment t2, vacuum or micro-reducing atmosphere heat treatment t3 and dynamic inert gas partial pressure heat treatment, the total treatment time of the whole recovery heat treatment is 2-10 h, the temperature range of the recovery heat treatment is Ts-150 DEG C to Ts, and Ts is the solid solution temperature. By improving the heat treatment process, recrystallization of the single crystal casting caused by local plastic strain in the casting process is relieved or even eliminated.

The invention discloses a high-entropy ceramic thermal barrier coating and a preparation method thereof, and relates to the technical field of thermal barrier coating materials. The method comprises the following steps: mixing ZrO2, HfO2, Ta2O5 and various rare earth oxides, and carrying out high-energy wet ball milling, drying, solid solution sintering and crushing to prepare submicron high-entropy ceramic powder; mixing the modified powder with aluminum sol obtained by hydrolyzing aluminum isopropoxide, rare earth nitrate and the like, dispersing, drying and carrying out heat treatment to obtain modified powder coated with aluminum oxide nanoparticles on the surface; carrying out spray drying granulation to obtain spherical agglomerated powder; and finally, a DD6 single-crystal high-temperature alloy matrix is subjected to sand blasting and pre-oxidation treatment, agglomerated powder is deposited on the surface of the matrix through a plasma spraying vapor deposition technology, a columnar crystal coating is formed, and a finished product is obtained through vacuum annealing. The coating prepared through the method is uniform in structure and high in bonding strength, thermal shock resistance and high-temperature phase stability are remarkably improved, and the coating is suitable for surface protection of aero-engine hot end components.

The invention discloses a method and a device for predicting spatial and temporal distribution characteristics of a microstructure of a nickel-based single-crystal high-temperature alloy under creep-oxidation interaction, and belongs to the technical field of high-temperature structural material service performance prediction.The method comprises the following steps: performing creep tests of different temperatures, stresses and durations based on vacuum and atmospheric environments respectively; obtaining microstructure morphology characteristics and microscopic parameter distribution in the nickel-based single crystal superalloy under different environments and test conditions; quantifying the spatial-temporal distribution evolution law of the volume fractions of gamma'phases in the creep samples under different temperatures and stresses in vacuum and atmospheric environments; establishing a periodic cell element model and a microstructure evolution model; and predicting the spatio-temporal evolution law of the channel width of the gamma-phase matrix in the stress creep sample at different temperatures in the atmospheric environment. According to the method, spatial and temporal distribution of the microstructure caused by interaction of creep and oxidation is considered, a microstructure evolution behavior prediction framework is constructed in combination with a physical mechanism, and the distribution rule of the microstructure is accurately described.

The application discloses a kind of high plasticity single crystal high-entropy high-temperature alloy without Fe and Ti and a preparation method thereof.The chemical composition of the alloy includes Co, Ni, Cr, Al, Ta, Mo and W seven elements, and the atomic percentage of each element is Co 35-45at%, Ni 30-40at%, Cr 3-5at%, Al 10-13at%, Ta 1-4at%, Mo 1-3ar% and W 3-5at%.The preparation method includes the following steps: sequentially putting elemental Co, Ni, Cr, Ta, Mo and W into the crucible of vacuum induction melting furnace for heating and melting, adding elemental Al when the temperature rises to the refining temperature, and pouring into master alloy ingot;using high-speed solidification Bridgeman method and seed crystal method to prepare single crystal high-entropy high-temperature alloy test rod with <001> grain orientation;and sequentially carrying out solid solution treatment, primary aging and secondary aging on the single crystal high-entropy high-temperature alloy test rod, to obtain the high plasticity single crystal high-entropy high-temperature alloy without Fe and Ti.The single crystal high-entropy high-temperature alloy of the application has the advantages of high-entropy alloy and single crystal high-temperature alloy, and has excellent room temperature and high temperature mechanical properties.

The application discloses a kind of second generation nickel-based single crystal superalloy recrystallization defect simulation and control method.The method steps are: according to sample preparation wax mold, after sand blasting, dry baking, manufacture ceramic shell;Through directional solidification preparation second generation nickel-based single crystal superalloy sample, control pulling speed, holding temperature and temperature gradient and other parameters;According to service condition preparation sample, simulate stress loading, in combination with heat treatment simulate actual service environment;Using electron backscattering diffraction and X-CT imaging, characterize recrystallization grain orientation distribution, three-dimensional morphology, content and thickness.Process parameter-defect characteristic mapping relationship is established, the stress distribution characteristics during preparation are clarified, the ceramic shell and preparation process are feedback controlled, and the control of recrystallization defects is realized.The application simulates the actual service environment of high-temperature alloy blade, and restores the performance of recrystallization defect sample in actual service environment.The application provides an experimental reproduction method and effective process control strategy for recrystallization defect research.

The application discloses a design method and system of a single-crystal high-temperature alloy solid solution heat treatment system, relates to the cross technical field of numerical simulation and material processing, and comprises the following steps: based on the relationship between element concentration and solidus temperature, determining the solidus temperature distribution of a cast single-crystal high-temperature alloy sample according to the element concentration distribution extracted from the cast single-crystal high-temperature alloy sample; adopting a phase field method to simulate solid solution heat treatment of the cast single-crystal high-temperature alloy sample, so as to obtain the element concentration distribution under the initial melting temperature and heat preservation for one simulation time step, and mark the element concentration distribution after treatment as the element concentration distribution, and determine the segregation coefficient of each element; when the segregation coefficients of all elements are within a preset range, marking all initial melting temperatures and corresponding current simulation times as heat treatment simulation results, and then determining the actual solid solution heat treatment system of the cast single-crystal high-temperature alloy sample. The application has the advantages of short time consumption, high efficiency and low cost.

The invention belongs to the technical field of alloy hydrogen embrittlement resisting processes, and relates to a hydrogen embrittlement resisting nickel-based single crystal high-temperature alloy and a preparation method thereof. Comprising the following steps: weighing simple substance raw materials of Ni, Cr, Co, Mo, W, Ta, Al, Re, Nb, Hf and C, smelting the raw materials for multiple times to obtain a mother alloy ingot of the nickel-based single crystal superalloy, processing the mother alloy ingot into a rod, cleaning, drying, heating to a preset temperature in an argon atmosphere, preserving heat for a preset time at the preset temperature, and cooling to obtain a nickel-based single crystal superalloy test rod; the method comprises the following steps: carrying out gradient solid solution heat treatment on a nickel-based single-crystal high-temperature alloy test bar, cooling to obtain a solid-solution nickel-based single-crystal high-temperature alloy test bar, and carrying out primary aging heat treatment to obtain the hydrogen embrittlement-resistant nickel-based single-crystal high-temperature alloy. The nickel-based single crystal superalloy prepared by the method disclosed by the invention can still keep relatively high elongation and reduction of area after being charged with hydrogen, the hydrogen embrittlement sensitivity of the nickel-based single crystal superalloy is obviously lower than that of a solid solution structure, and the nickel-based single crystal superalloy shows excellent comprehensive performance.

The invention discloses a (Ni, Pt) Al / Ni composite coating of a single-crystal high-temperature alloy, the composite coating takes the single-crystal high-temperature alloy as a matrix, the composite coating is a single-layer coating formed by single-phase beta-(Ni, Pt) Al, and no mutual diffusion zone exists between the composite coating and the matrix. The preparation method comprises the following steps: firstly, pre-electroplating Ni on the surface of the substrate as a transition layer, then electroplating a Pt layer, carrying out hydrogen removal and diffusion vacuum annealing treatment and high-temperature low-activity gas phase aluminizing treatment, and finally, forming the composite coating on the surface of the substrate. The composite coating and the pre-plated Ni layer are introduced as a diffusion barrier layer, so that direct contact between the Pt layer and the matrix is effectively blocked, mutual diffusion between the Pt layer and the matrix is inhibited, damage to a coherent phase structure in the matrix and formation of a TCP precipitated phase caused by mutual diffusion of Ni and Al are delayed, formation of a secondary reaction zone is delayed, and the material stability is ensured. The composite coating provided by the invention is a high-temperature protective coating with slow oxidation weight gain at high temperature.

The invention belongs to the technical field of laser additive manufacturing, and particularly discloses a nickel-based single crystal superalloy laser additive preparation method and device system. The device system comprises a forming table top, a laser cladding wire feeding assembly, a cooling device and a direct-current power source. The forming table board consists of a seed crystal unit, a cooling unit and a supporting unit which are integrally formed and made of a nickel-based single crystal high-temperature alloy material; the laser cladding wire feeding assembly is composed of a laser generator and a wire feeding mechanism. The cooling device communicates with the cooling unit of the forming table top through a pipeline, the positive electrode of the direct-current power source is connected with the seed crystal unit of the forming table top, and the negative electrode of the direct-current power source is connected with the nickel-based single-crystal high-temperature alloy wire of the laser cladding wire feeding assembly. According to the device system, the stability and high temperature gradient between the forming table top and the molten pool in additive manufacturing can be ensured, and crystals are promoted to grow in the specific direction, so that the selectivity of the crystals is improved, and formation of mixed crystals in the additive manufacturing process is inhibited.

The invention discloses a low-density low-rhenium nickel-based single-crystal high-temperature alloy which comprises the following chemical components in percentage by weight: 2.8 to 6 percent of chromium, 5.5 to 9 percent of cobalt, 4 to 7 percent of molybdenum, 4 to 6 percent of tungsten, 4 to 7 percent of tantalum, 4 to 7 percent of aluminum, 0.07 to 0.3 percent of hafnium, 2 to 4 percent of rhenium, 1.5 to 2.5 percent of ruthenium, 0 to 0.01 percent of yttrium and the balance of nickel. Wherein in percentage by weight, the content relation of the molybdenum and the tungsten is 0.7 lt; molybdenum / tungsten lt; the content relation of molybdenum and rhenium is that molybdenum / rhenium is greater than or equal to 1.1. The strength of the alloy is improved by increasing the content of molybdenum, the contents of tungsten and rhenium are reduced, precipitation of harmful phases is reduced by comprehensively regulating and controlling the proportion of elements in rows and columns, it is ensured that the creep life of the alloy reaches the fourth-generation single crystal level, meanwhile, the alloy has the room-temperature density not higher than 8.9 g / cm < 3 >, the high-temperature low-stress durability of the alloy reaches the typical fourth-generation single crystal high-temperature alloy level, and the service life of the alloy is prolonged. The method is suitable for manufacturing advanced aero-engines.

The invention relates to a bonding connection method of nickel-based single crystal superalloy and an obtained product. The method comprises the following steps that two or more nickel-based single-crystal high-temperature alloy blocks to be bonded and connected are provided, and the surface roughness Sa value of the surfaces to be bonded of the nickel-based single-crystal high-temperature alloy blocks is 80 nm or lower; carrying out bonding connection on the nickel-based single-crystal high-temperature alloy block material in a vacuum environment under the pressure intensity of 20-100 MPa; and cooling to obtain the bonded nickel-based single-crystal high-temperature alloy connecting piece of which the microstructure at the bonding interface is consistent with that of the original single-crystal high-temperature alloy block. The bonding connection nickel-based single-crystal high-temperature alloy product obtained by the method can realize direct bonding combination among atoms on a bonding interface, and has a microstructure equivalent to that of a base material and excellent mechanical properties.

The application discloses a material for connecting single-crystal superalloy and polycrystal superalloy and a preparation and use method thereof, and the material comprises low-melting-point Ni-Ti alloy powder and high-melting-point Ni-based alloy powder. The material can realize rapid high-performance connection of the single-crystal superalloy and the polycrystal superalloy. The application belongs to the technical field of alloy material connection.

The invention provides a nickel-based single-crystal high-temperature alloy component laser epitaxy repairing method based on energy field regulation and dynamic crystal selection. The nickel-based single-crystal high-temperature alloy component laser epitaxy repairing method comprises the steps that a damaged area is subjected to cleaning treatment and three-dimensional scanning, matrix crystallographic orientation is obtained, a three-dimensional thermal-structure finite element simulation model is established, and a repairing basic process is determined; homogeneous alloy powder is adopted, a laser machining head with a coaxial powder feeding nozzle is used for repairing the damaged area, in the repairing process, auxiliary induction heating is conducted, and the temperature field and the morphology of a molten pool are monitored; if the G / R is lower than the preset critical threshold value, the auxiliary induction heating power is dynamically enhanced; if the tail of the molten pool is disturbed, an ultrasonic vibration field is applied to the molten pool; and treating after repairing. A repair system is also provided. According to the method, the epitaxial growth of the single crystal consistent with the crystallographic orientation of the matrix can be dynamically guided, so that the nickel-based single crystal high-temperature alloy component can be repaired, the repair success rate and the structure consistency are remarkably improved, and the epitaxial proportion of the single crystal is increased to 95% or above.

This invention relates to the field of high-temperature alloy technology, specifically to a method for improving the microstructure stability of single-crystal high-temperature alloys by controlling the nitrogen (N) content. The content of refractory elements in single-crystal high-temperature alloys increases with increasing heat resistance, leading to decreased microstructure stability and increased precipitation of topologically close-packed (TCP) phases, resulting in decreased mechanical properties. Based on the influence of N on the TCP phase precipitation behavior in high-temperature alloys, this invention proposes a method to effectively improve the microstructure stability of single-crystal high-temperature alloys by controlling the N content. By adding a certain amount of CrN or AlN during directional solidification to ensure an N mass content of 15-30 ppm in the single-crystal alloy, the amount of TCP phase precipitates in the alloy microstructure is significantly reduced after long-term high-temperature heat exposure, and the microstructure stability of the single-crystal alloy is significantly improved. This invention employs a simple and feasible method to effectively improve the microstructure stability of single-crystal high-temperature alloys.

The invention discloses cobalt-based brazing filler metal for brazing single-crystal superalloy DD10 and a preparation method and a brazing method of the cobalt-based brazing filler metal, and belongs to the field of nickel-based superalloy brazing. The cobalt-based brazing filler metal comprises, by atomic ratio, 10%-12% of Ni, 6%-8% of Cr, 5%-7% of Al, 5%-6% of Ta, 3%-5% of Ti, 2%-5% of Pt, 2%-4% of Ga, 2%-3% of Re, 2%-3% of V, 1%-2% of Ir, 1%-2% of In, 1%-2% of Mn, 0.5%-1% of Y, 0.5%-0.9% of C, 0.1%-0.25% of Ce and the balance Co. Compared with traditional cobalt-based brazing filler metal, wettability between the brazing filler metal and base metal is improved, joint interface bonding is enhanced, the joint structure is optimized through solid solution strengthening, grain boundary strengthening, precipitation strengthening, dispersion strengthening and other mechanisms, the joint performance is improved, the invention further provides a brazing method of the single-crystal high-temperature alloy DD10, the designed brazing filler metal is placed between the upper layer of single-crystal high-temperature alloy DD10 base metal and the lower layer of single-crystal high-temperature alloy DD10 base metal, brazing is conducted in a vacuum brazing furnace, the structure of a single-crystal high-temperature alloy DD10 brazing joint is improved, the mechanical property of the joint is improved, and technical support is provided for high-strength and high-toughness connection of the single-crystal high-temperature alloy DD10.

The invention provides a structure and a method for producing a single-crystal blade with specific orientation, and relates to the technical field of directional solidification casting of single-crystal high-temperature alloy blades. The structure for producing the single crystal blade with the specific orientation comprises a seed crystal mold shell and a blade mold shell, a seed crystal is arranged in the seed crystal mold shell, a threaded section is arranged between the seed crystal mold shell and the blade mold shell, a straight section parallel to the seed crystal is arranged at one end, close to the seed crystal mold shell, of the threaded section, an included angle alpha is formed between the seed crystal and the horizontal plane, and the included angle alpha is larger than alpha. 55 degrees > alpha > 35 degrees, and the blade mold shell is perpendicular to the horizontal plane. The structure can be used for preparing the single crystal blade with any specific orientation, and is simple in preparation process, high in feasibility, high in percent of pass and suitable for batch production.

The invention belongs to the technical field of alloy heat treatment, and provides a customized solid solution heat treatment method and system for nickel-based single crystal superalloys with different drawing rates and electronic equipment. The method comprises the steps of solution treatment temperature window determination, temperature function construction, constraint condition setting, optimization target setting, improved model construction, data acquisition, parameter fitting and optimization iteration. According to the method, the solid solution scheme is precisely customized by improving the model, and multi-constraint control and precise parameter testing are combined, so that the required time is shortened on the premise of avoiding substandard solid solution sufficiency and large-size initial melting hole generation probability, and the overall efficiency is improved; by introducing two temperature-related functions and setting double constraints, the defect of incomplete solid solution or excessive holes is avoided.

The application discloses a single-crystal high-temperature alloy primary orientation test method, device and storage medium, which is used for improving the stability, reducing the relative error, increasing the alloy quantity of primary test and improving the test efficiency. The test method disclosed by the application comprises the following steps: testing the primary orientation of an alloy to obtain a Laue diffraction spot spectrum; calibrating the Laue diffraction spot spectrum, and determining a conversion matrix of a test reference coordinate system and a sample coordinate system according to a calibration result; and determining a primary orientation deviation according to the conversion matrix. The application further provides a single-crystal high-temperature alloy primary orientation test device and a storage medium.

The application provides a third-generation nickel-based single crystal superalloy and a composition design method and a preparation method thereof. V The application comprises the following steps: determining the element type of the nickel-based single crystal superalloy to be designed, screening the composition from different element compositions of the alloy to meet N The application can obtain the nickel-based single crystal superalloy with excellent high-temperature creep performance through the design method, and the creep life of the nickel-based single crystal superalloy can reach 388h under the condition of 1100 DEG C and 137MPa.

The invention provides a composite diffusion barrier and a preparation method thereof, and relates to the technical field of high-temperature alloys and thermal barrier coatings. The composite diffusion barrier is composed of a nano Al2O3 layer and a dispersed nano carbide (MxCy) layer and is used for stabilizing a coating / Ni3Al-based single-crystal high-temperature alloy matrix interface under the high-temperature condition. The preparation method comprises the following steps: firstly, carrying out pretreatment on the surface of the single-crystal high-temperature alloy, then carrying out gas-phase carburization, and controlling the diffusion speed of Al and C by adjusting the atmosphere in the carburization process to obtain the nano Al2O3 layer and dispersed nano carbide (MxCy) composite diffusion barrier. According to the method, diffusion paths of aluminum, titanium, molybdenum and the like of the matrix can be effectively limited, the diffusion rate of the aluminum, the titanium, the molybdenum and the like can be reduced, and finally the mutual diffusion degree of elements between the coating and the matrix under the service condition is slowed down, so that the high-temperature oxidation resistance and the corrosion resistance of the alloy are improved, and the stability of a coating / alloy interface is enhanced. In addition, the method provided by the invention is simple in process, low in cost, high in repeatability and beneficial to popularization and engineering application.

The present application relates to single crystal alloy casting defect control technical field, especially to a kind of trace element / microelement carbon reduction method for reducing micro-pore in the casting process of nickel-based single crystal superalloy.The present application is aimed at different alloy system, and target carbon content is determined by thermodynamics-solidification simulation, so that carbide starts to precipitate when solid phase mass fraction is 80%~90% during solidification, thereby promoting interdendritic residual melt feeding at the end of solidification when feeding channel is not completely closed, and the purpose of significantly reducing the porosity of single crystal casting is achieved.The present application is not limited to all alloys with fixed content range, but determines the corresponding carbon content according to the solidification characteristics of each alloy system, so it can be applied to single crystal alloys of different systems.

The invention belongs to the technical field of single-crystal high-temperature alloy recrystallization control, and discloses a single-crystal high-temperature alloy recrystallization control method based on eutectic and dislocation net regulation and control. The method comprises the following steps: 1, carrying out macroscopic corrosion treatment on an as-cast or deformed single-crystal high-temperature alloy sample, and removing eutectic crystals on the surface layer of the as-cast or deformed single-crystal high-temperature alloy sample; 2, heating the single-crystal high-temperature alloy sample treated in the step 1 from room temperature to trough temperature, and carrying out high-temperature circulating heat treatment for multiple times; and 3, carrying out standard heat treatment on the single-crystal high-temperature alloy sample subjected to the last high-temperature circulating heat treatment process. According to the method, the recrystallization driving force introduced by plastic deformation can be efficiently and stably reduced, so that the formation of a recrystallization structure is effectively inhibited in the subsequent solid solution heat treatment, and the method is suitable for industrial production.

A nickel-based single crystal superalloy brazing repair material comprises a first brazing filler metal and a second brazing filler metal, wherein the first brazing filler metal comprises a brazing powder, and the second brazing filler metal comprises a mixture of the brazing powder and a base metal powder which is the same as the material of the part to be repaired; wherein the brazing powder comprises 8-18% of Cr, 3-12% of Co, 1-6% of W, 1-6% of Ta, 2-6% of Al, 1-5% of B, not more than 4% of Mo, not more than 5% of Hf, not more than 3% of Re, and the balance of Ni and inevitable impurities; and the weight ratio of the brazing powder in the second brazing filler metal is 5-50%. The repair material can effectively braze repair large-size gaps of more than 0.25 mm. The application also provides a nickel-based single crystal superalloy brazing repair method.

The invention discloses a rhenium-free nickel-based single-crystal high-temperature alloy and a preparation method thereof, and relates to the technical field of high-temperature alloys. According to the high-temperature alloy provided by the invention, by finely regulating and controlling the proportion of strengthening elements such as Al, Ti, Ta and W and synergistically exerting the auxiliary effects of elements such as Cr, Co, C and Hf, after an expensive rhenium (Re) element and a molybdenum (Mo) element which is easy to promote generation of a harmful phase are thoroughly abandoned, collaborative optimization of high strength, high structure stability, excellent oxidation resistance and good casting performance is successfully realized. The rhenium-free nickel-based single crystal superalloy provided by the invention has high performance, high stability, excellent oxidation resistance and hot corrosion resistance and good castability, and provides an ideal material solution for low-cost and high-reliability manufacturing of high-temperature parts of heavy duty gas turbines.

The present application relates to the field of nickel-based single crystal superalloy blade investment casting, in particular to a method for preparing yttria coating on modified ceramic core by ultrasonic impregnation. The surface of the silicon-based ceramic core is modified by using silane coupling agent to improve the adhesion of the coating and reduce the risk of coating peeling. During the preparation of the coating, the ultrasonic impregnation can increase the permeability of the liquid coating, promote the penetration of the coating solution into the small pores of the silicon-based ceramic core, and further enhance the adhesion of the coating, so as to form a uniform and firm protective coating on the surface of the silicon-based ceramic core. The scheme is green and environmentally friendly, easy to operate, and suitable for various types of coatings, including metal, oxide, polymer and other materials, and has wide applicability.