658 results about "Diffusion welding" patented technology

The invention belongs to the technical field of metal forming machining, and provides a variable-curvature thin-wall micro-channel structure manufacturing process which comprises the steps that a channel is machined in the front face of a raw material plate, a bottom plate is obtained, and the channel is provided with an arc-shaped protruding groove bottom; diffusing and welding a cover plate on the front surface of the bottom plate to cover the bottom plate to obtain a first prefabricated plate; the back face of the first prefabricated plate is machined to enable the bottom of the channel to be provided with a groove with the same shape as the groove bottom of the arc-shaped protrusion, and a second prefabricated plate is obtained; and the second prefabricated plate is pressed by the mold to obtain the variable-curvature thin-wall micro-channel structure. The thin-wall micro-channel structure is split into a combined structure of the cover plate and the bottom plate, and the variable-curvature thin-wall micro-channel structure is obtained by pressing and forming the cover plate and the bottom plate through a mold after the cover plate and the bottom plate are combined. According to the variable-curvature thin-wall micro-channel structure, the channel is formed in the bottom plate, arc compensation is conducted on the channel of the bottom plate by arranging the arc-shaped protruding groove bottoms according to the different curvatures of the bottoms of all the micro-channels of the variable-curvature thin-wall micro-channel structure, it can be guaranteed that the wall thicknesses of the bottoms of the micro-channels are consistent, and cracking in the profiling process is avoided.

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 relates to a copper-aluminum composite heat dissipation plate forging and pressing manufacturing process and a copper-aluminum composite heat dissipation plate. The process comprises the steps that S1, assembling is conducted, specifically, an aluminum plate and a copper plate are stacked, and a double-layer plate is obtained; s2, welding is conducted, specifically, the aluminum plate and the copper plate are compounded in a diffusion welding mode, the junction position of the aluminum plate and the copper plate is welded to form a diffusion layer, and a double-layer welded plate is obtained; the double-layer welding plate is extruded and stretched through a hydraulic machine to form the copper-aluminum composite heat dissipation plate, forming holes are formed in a template, facing an aluminum plate, of the hydraulic machine, the aluminum plate is extruded through the forming holes, heat dissipation protrusions of an aluminum-clad copper structure are formed on the copper-aluminum composite heat dissipation plate, the width of the heat dissipation protrusions is larger than 1.5 mm, and the heat dissipation protrusions are arranged on the aluminum plate; and the thickness of the aluminum layer on the surface of the heat dissipation bulge is not less than 0.1 mm. The copper-aluminum composite heat dissipation plate is manufactured through the process. According to the technology, the copper-aluminum composite heat dissipation plate can be obtained through a simple manufacturing method, the high heat conductivity of copper and the corrosion resistance of aluminum are compatible, and connection at the copper-aluminum interface is reliable.

The invention discloses a connecting method of an FGH99 double-radial-plate turbine disc based on a nanocrystallization high-entropy alloy middle layer, and belongs to the technical field of welding. A high-entropy alloy middle layer is adopted, nanocrystallization treatment is combined to optimize a microstructure, the nanocrystallization high-entropy alloy middle layer is arranged between an upper FGH99 double-radial-plate turbine disc and a lower FGH99 double-radial-plate turbine disc, diffusion connection is conducted in a vacuum diffusion welding furnace, and the welded FGH99 double-radial-plate turbine disc is obtained. Low-damage solid-phase diffusion bonding is achieved at the welding temperature lower than the solid solution temperature of base metal; meanwhile, the nanocrystallization interlayer structure promotes element diffusion, the diffusion welding period can be greatly shortened, the problems of grain coarsening and performance degradation of a heat affected zone caused by long-time heat preservation in a traditional technology are solved, the technical bottleneck of cooperative regulation and control over the strength and toughness of a high-temperature alloy complex component connection interface is broken through, and the application prospect is wide. And a high-reliability solution is provided for efficient manufacturing of the double-radial-plate turbine disc of the aero-engine, and the double-radial-plate turbine disc is particularly suitable for the long-service-life service requirement under the working conditions of extreme high temperature and cyclic loads.

The invention discloses a tungsten and copper alloy diffusion welding method and a tungsten / copper alloy welding part, and relates to the field of heterogeneous metal diffusion welding. A diffusion welding method for tungsten and copper alloy comprises the following steps that pure copper is softened and annealed; finish machining; the to-be-welded surfaces of tungsten and pure copper are polished and subjected to acid pickling; tungsten and pure copper are cleaned, baked and degassed; tungsten, pure copper and pure iron are combined and subjected to high-temperature diffusion welding, and a tungsten / pure iron / pure copper composite part is obtained; the tungsten / pure iron / pure copper composite part and the copper alloy are subjected to finish machining, the to-be-welded faces of the tungsten / pure iron / pure copper composite part and the copper alloy are polished to be bright, and then acid pickling treatment, ultrasonic cleaning and baking degassing are conducted; and the tungsten / pure iron / pure copper composite part and the copper alloy combination are subjected to diffusion welding, and a tungsten / copper alloy welding part is obtained. The method solves the problems that a single-layer copper intermediate layer is difficult to form metallurgical bonding with tungsten, interface defects are easy to form during casting, and the interface thermal conductivity of a single-layer iron intermediate layer is insufficient.

Provided in the present invention is a method for the low-temperature solid-phase connection of a chip under air conditions. The method comprises the following steps: step S1, cleaning and drying the surfaces of a chip and a substrate; step S2, depositing a nano metal layer on the back surface of the chip, and depositing a nano metal layer on the substrate, wherein the nano metal layer is a nano Ag coating layer or a nano Au coating layer; step S3, placing the chip on the substrate, such that the nano metal layer of the chip is opposite to the nano metal layer of the substrate, thereby forming a packaging structure which sequentially comprises the chip, the nano metal layer on the chip, the nano metal layer on the substrate, and the substrate from top to bottom; and step S4, placing the assembled packaging structure in a hot-pressing diffusion welding device to perform hot-pressing heat preservation in an air atmosphere, and cooling same to room temperature to finish interconnection, wherein the hot-pressing temperature does not exceed 300°C. The joint interconnection interface obtained by using the technical solution of the present invention is well bonded, the connection layer is dense without any pore defects, the thermal conductivity is good, and the strength is high.

The invention discloses a first wall structure for a nuclear fusion reactor, which comprises a tungsten armor, a front wall, a fin array and a rear wall which are sequentially connected through a diffusion welding process. A wing-shaped fin array is arranged between the front wall and the rear wall, a formed cavity serves as a coolant flow channel, and coolant enters the first wall through a set inlet and a set outlet. Due to disturbance of the fins, boundary layer separation and reattachment are generated between the adjacent fins, the heat exchange effect between the main flow and the boundary layer is remarkably enhanced, the heat exchange area is effectively increased, and therefore the heat exchange performance of the first wall is enhanced. The wing shape adopted by the invention is an excellent hydrodynamic appearance, and flow separation can be effectively reduced, so that the generation of separation vortexes can be greatly reduced, and the pressure loss of fluid can be effectively reduced.

The invention relates to manufacturing equipment and a manufacturing method of a micro-channel heat exchanger core, and belongs to the technical field of micro-channel heat exchangers. The manufacturing method comprises the steps that a plurality of runners are formed in the surfaces of core plates, the core plates are stacked to form a core body, the core body is placed in diffusion welding equipment, pre-tightening pressure is applied to the core body, and a furnace body of the diffusion welding equipment is vacuumized; the furnace body is vacuumized, heated and subjected to heat preservation, meanwhile, inert gas is introduced into all the flow channels of the core body, and the temperature of the inert gas is gradually increased; after the temperature rises to a preset temperature, inert gas in the furnace body is pumped out, a radiation heating method is adopted for continuous heating, welding pressure is applied to the core body, and welding is completed; and inert gas is introduced into the furnace body for cooling, and meanwhile inert gas is introduced into each flow channel of the core body for step-by-step cooling. Therefore, the heating and cooling time of the heat exchanger core body can be shortened, the welding efficiency is improved, and the intergranular sensitization tendency of materials is improved.

The invention provides a metal riveting structure for an alumina fiber battery shell and a preparation method. The problem of debonding caused by thermal expansion difference and insufficient interface bonding force in traditional metal and ceramic riveting is solved. The structure comprises a metal riveting piece, a connecting layer and a transition layer, a connecting rod of the metal riveting piece penetrates through an inner threaded hole of the connecting layer and goes deep into a stepped groove of the transition layer, and double connection of threaded screwing and stepped groove mechanical embedding is formed; a metal ceramic gradient layer is arranged between the transition layer and the connecting layer and is matched with a thermal expansion coefficient; the thickness of the diffusion layer is 10-100 microns, and the shear strength of the diffusion layer is larger than or equal to 50 MPa. The structure obviously increases the contact area, relieves the thermal stress, improves the interface strength and the long-term reliability in a wide temperature range, and is suitable for high-temperature battery shell connection.

The invention relates to the technical field of brazing, in particular to a heterogeneous material brazing joint and a preparation method thereof. The preparation method comprises the following steps that S1, a porous metal net is placed on the surface of a to-be-welded steel substrate for diffusion welding, and the steel substrate with the surface configuration is obtained; and S2, the configuration face of the steel base body serves as a face to be welded, the steel base body with the surface configuration is assembled with brazing filler metal and a titanium base body to be welded, and then vacuum brazing is conducted. According to the method, the porous metal net is welded to the surface of the steel substrate to be welded through diffusion welding, a periodic heterogeneous microstructure surface is formed on the steel substrate, a discontinuous mismatched and multi-phase alternating interface structure is constructed in a customized mode, a continuous stress line of a connector can be cut off, rapid initiation and rapid expansion of cracks are restrained, and strengthening and toughening brazing connection of titanium and steel can be achieved.

The invention belongs to the technical field of material welding, and discloses a titanium alloy welding method which comprises the following steps: pretreating a to-be-welded surface of a titanium alloy; the pretreated to-be-welded surface is subjected to sand blasting treatment and magnetron sputtering treatment, and an iron film is sputtered on the to-be-welded surface; the titanium alloy with the to-be-welded surface sputtered with the iron film is subjected to annealing treatment in the argon atmosphere; and the to-be-welded surface of the sputtering iron film is welded through a diffusion welding process. According to the characteristic that the iron element can promote mutual diffusion of the titanium alloy, surface sand blasting, magnetron sputtering, stress relief annealing and diffusion welding processes are combined, so that the titanium alloy is tight in interface connection and complete in grain, the plasticity is not obviously reduced while the strength of the titanium alloy is kept, and the requirement for large-scale and integrated aero-engines can be met.

The invention discloses an IC21 single-crystal high-temperature alloy diffusion welding method based on multi-field assistance and a high-entropy interlayer, and belongs to the technical field of welding. Nano high-entropy intermediate layer foil composed of 35% of Ni, 22% of Cr, 20% of Al, 7% of Re, 5% of Ta, 2% of Y, 7.5% of Si and 1.5% of B is adopted and placed between an upper layer IC21 single-crystal high-temperature alloy and a lower layer IC21 single-crystal high-temperature alloy, liquid-phase diffusion welding is conducted in a vacuum diffusion welding furnace by introducing the multi-field coupling effect of an ultrasonic vibration field, a pulsed magnetic field and an electric field, energy field superposition is achieved through multi-field coupling through space-time cooperation, and the high-temperature alloy is obtained. The pulse frequency of the ultrasonic vibration field is matched with the alternating frequency of the magnetic field; a diffusion channel is opened by an electric field, dendritic crystal regulation and defect repair are realized by mid-term superposition of an ultrasonic vibration field and a pulsed magnetic field, finally directional migration and dendritic crystal segregation suppression of a liquid film are realized, the technical bottleneck of high-integrity connection of an ultrathin-wall structure of a single-crystal turbine blade is broken through, and the extreme working condition service requirement of a sixth-generation engine is met.

The utility model relates to the technical field of diffusion welding, in particular to an open type diffusion welding device with size adaptability, which comprises a device base, two movable plates are arranged on the upper surface of the device base, and adjusting motors are fixed at two ends of the device base through bolts. A power output shaft of the adjusting motor penetrates through the device base to be connected with a lead screw, the lead screw is in threaded connection with the movable plate, and a guide rod fixedly connected with the device base penetrates through the interior of the movable plate. According to the automatic welding device, the clamping plate is driven by the clamping electric cylinder on the feeding piece to vertically move, so that materials are clamped and fixed, the clamping plate is prevented from deviating during movement, the anti-skid convex points on the clamping plate can play an anti-skid role, the situation that the welding quality is affected due to displacement of the materials is avoided, and the two adjusting motors are started, so that the welding quality is guaranteed. The two movable plates drive the two lead screws to rotate respectively, and the two movable plates move relatively, so that the two feeding pieces are driven to get close to each other, and automatic feeding is achieved.

The invention relates to a stirring friction pretreatment method for an aluminum alloy diffusion welding grain refinement surface, which comprises the following steps: starting from edge lines of a pair of to-be-welded surfaces of an aluminum alloy to-be-welded part, respectively carrying out multi-pass continuous equidistant stirring friction processing on the pair of to-be-welded surfaces, and ensuring that the translation overlapping rate of a stirring needle track between passes is 25-50%; during friction stir processing, water is continuously added for cooling, so that a spiral deformed fine grain layer with the grain size of 50-80 microns and the thickness of 1-2 mm is generated on a pair of to-be-welded surfaces at the position of a columnar stirring needle; and milling the pair of surfaces to be welded after the stirring friction processing is completed until the roughness is Ra 0.1-Ra 0.3, so as to obtain the aluminum alloy diffusion welding grain refinement surface. Compared with a welding seam obtained through a direct diffusion welding method, the welding seam obtained through the method has the higher welding rate and the higher strength, a new thought is provided for production and manufacturing of aluminum alloy, and the method has important significance in improving performance indexes and enhancing service reliability.

A method for determining the quality of diffusion welding by means of non-destructive testing comprises the steps of determining a testing method, performing batch testing, establishing a relationship, performing a classification of the mechanical performance data of welded joints, performing a classification of quality levels of different welded interfaces, performing a classification of quality levels of the welded joints, and determining quality levels of the welded joints of to-be-tested workpieces.

The invention discloses a manufacturing method of a high-speed asynchronous motor rotor. A plurality of grooves are formed in the steel side wall of the rotor; brazing filler metal is sprayed on the surface of the conducting bar to obtain a sprayed conducting bar; assembling the spraying conducting bar into the groove to form an assembly body, wherein the conducting bar protrudes out of the side wall of the rotor steel; an outer lantern ring with the expansion coefficient smaller than that of the guide strip is sleeved outside the assembly body; vacuum diffusion welding is carried out, and the outer lantern ring extrudes the conducting bar under the difference of expansion coefficients of the outer lantern ring and the conducting bar; after vacuum diffusion welding is finished, the outer lantern ring is taken out to obtain a welded body; end ring areas are machined at the two ends of the welding body; the end ring area is sleeved with an end ring, the end ring and the welding body are combined, and the end ring is connected with the guide strip. The outer sleeve is arranged outside, axial extrusion force is provided for the conducting bar at the high temperature of vacuum diffusion, so that contact pressure adjustment needed by diffusion welding is achieved, and the welding strength of the conducting bar and a rotor steel assembly face is guaranteed; and the grooves are formed in the side surfaces, so that the conducting bars can be assembled deeper, and the skin effect is reduced.

The invention discloses an anode porous transmission layer for PEM water electrolysis hydrogen production and a preparation method of the anode porous transmission layer. The preparation method comprises the steps that firstly, a porous titanium plate and a titanium mesh are washed and dried after being subjected to acid pickling; secondly, absolute ethyl alcohol, polyvinyl butyral and titanium powder are evenly mixed to be prepared into slurry, and the slurry is sprayed to the two sides of the dried titanium mesh; and 3, stacking the porous titanium plate and the titanium mesh sprayed with the slurry, and forming metallurgical bonding through vacuum diffusion welding to obtain the anode porous transmission layer. The porous titanium plate and the titanium mesh are metallurgically bonded to prepare the anode porous transmission layer, the platinum plating amount is effectively reduced and the catalyst utilization rate is improved by regulating and controlling the thickness and the pore structure of the porous titanium plate and the plate-mesh stacking mode, and the gas-liquid transmission efficiency of the anode porous transmission layer is improved; and the anode porous transmission layer with strong mechanical support and high gas-liquid transmission efficiency is obtained, is suitable for PEM water electrolysis hydrogen production, and meets the development requirements of high efficiency and low cost of hydrogen production through renewable energy source and PEM water electrolysis coupling.

The invention provides a composite bar and a welding method. The welding method comprises the following steps that chemical and mechanical composite treatment is conducted on the surfaces of a 4J29 kovar alloy pipe and a TU1 oxygen-free copper bar; the TU1 oxygen-free copper rod is placed in a liquid nitrogen medium, and after the TU1 oxygen-free copper rod is cooled to-150 DEG C, assembling is conducted; the assembled 4J29 kovar alloy pipe and TU1 oxygen-free copper bar are placed in a furnace cavity of current-assisted vacuum diffusion welding equipment, a pressure head assembly is used for axial loading, and a pulse current meter is connected with the pressure head assembly; and the assembled 4J29 kovar alloy pipe and TU1 oxygen-free copper bar are subjected to current-assisted vacuum diffusion welding machining, and the 4J29 kovar alloy pipe and TU1 oxygen-free copper bar composite bar is obtained. According to the method, the interface diffusion behavior is regulated and controlled through cooperation of the pressure field, the temperature field and the current field, dissimilar welding of the 4J29 kovar alloy pipe and the TU1 oxygen-free copper bar is achieved, the microstructure of the composite bar obtained through the method shows that defects such as air holes and inclusions are not observed in a weld joint area, the process is simplified, and energy consumption is reduced.

The invention relates to a welding presetting method for a densely-arranged array group welding seam diffusion welding middle layer, and belongs to the technical field of aero-engines. The welding presetting method specifically comprises the following steps that a to-be-welded piece plate is prepared, and surface machining treatment is conducted on the to-be-welded piece plate; laying a middle layer on the surface of the to-be-welded plate; welding and fixing the two ends of the middle layer and the to-be-welded plate; carrying out multi-welding-spot welding and fixing on the middle layer and the position of each to-be-processed densely-arranged array column on the surface of the to-be-welded piece plate, and completing presetting of the middle layer; densely-arranged array columns and densely-arranged array column holes are machined in the to-be-welded piece plate with the preset middle layer, and the redundant middle layer is removed. According to the invention, proper presetting of the interlayer lamination is realized, the phenomena of hole blocking and hole shrinkage caused by melting of redundant interlayer alloy are eliminated, the influence of the redundant interlayer alloy on the performance of a base material after melting is avoided, and the manufacturing conformity and the use performance of the laminate cooling structure are improved.

The invention discloses a preparation method for obtaining a high-toughness joint through femtosecond laser treatment of nickel-based superalloy, and relates to the technical field of welding. The method comprises the following steps: pretreating the surfaces of two nickel-based high-temperature alloys to be welded; femtosecond laser treatment parameters are set, and femtosecond laser is adopted to conduct scanning treatment on the surfaces of the two pretreated nickel-based high-temperature alloys; and welding the two nickel-based high-temperature alloys subjected to femtosecond laser treatment by adopting TLP diffusion welding, and obtaining the high-toughness welding joint after welding is completed. According to the method, the optimal surface wettability of the nickel-based superalloy is obtained through femtosecond laser, melting reduction elements (such as B and Si) are diffused to the high-temperature nickel-based superalloy more quickly, the brittle phase of a connector is eliminated more quickly, the good connection effect is achieved at the low pressure and temperature through TLP diffusion welding, and compared with a traditional welding method, the welding defects can be effectively reduced, and the welding quality is improved. And the quality and performance of the joint are improved.

The invention relates to the technical field of copper-aluminum bars, in particular to a copper-aluminum polymer diffusion hybrid welding method which is characterized by comprising the following steps: S1, welding nickel sheets with bare copper: compounding the nickel sheets with the thickness of 0.1-0.3 mm on the welding surfaces of the copper bars; s2, nickel sheet polishing: mechanically polishing the nickel sheet until the surface roughness Ra is less than or equal to 0.8 mu m; s3, the aluminum row is polished, specifically, the welding face of the aluminum row is polished in a one-way mode through abrasive paper of 800-2000 meshes till the roughness Ra is smaller than or equal to 1.0 micron; s4, copper and aluminum composite welding is conducted, specifically, the copper bar with the polished nickel piece and the polished aluminum bar are composited through polymer diffusion welding, the welding temperature is 400-500 DEG C, the pressure is 10-20 MPa, and heat preservation is conducted for 30-60 minutes; the nickel sheet with the proper thickness is compounded on the welding surface of the copper bar, the binding force of a welding interface is enhanced, then the nickel sheet is subjected to precise mechanical polishing, it is ensured that the surface roughness of the nickel sheet reaches the extremely low level, the welding surface of the aluminum bar is subjected to fine grinding treatment, and the adaptability of the welding surface is improved; and tight combination of the copper bar and the aluminum bar is achieved at specific welding temperature, pressure and heat preservation time, and practicability is high.

The invention relates to the technical field of diffusion welding, in particular to a diffusion welding process for a large-area thin-plate structural member, which comprises the following steps of: additionally arranging flexible plates on contact surfaces of an upper welding tool and a corresponding to-be-welded plate as well as a lower welding tool and the corresponding to-be-welded plate respectively; and during diffusion welding, welding pressure is transmitted to the to-be-welded plate through the flexible plate. The diffusion welding process for the large-area thin-plate structural member aims to solve the problem that random and irregular defects are generated due to the fact that the surface of a plate of the large-area thin-plate structural member is uneven.

The machining method comprises the steps that S1, a plunger hole is machined in a steel base body, and the roughness of the inner surface of the plunger hole is not larger than Ra1.6; s2, a plunger bushing capable of being in interference fit with the plunger hole is machined according to the size of the plunger hole; s3, the plunger bushing is put into liquid nitrogen to be soaked and then taken out, then the plunger bushing is pressed into the plunger hole smeared with the soldering paste, a steel pin is embedded into the plunger hole, and a plunger assembly is obtained; through the thermal expansion effect of the steel pin, the plunger hole and the copper bush, the plunger bush is pressed to enter the plunger hole in the sintering process. And S4, the press-fitted plunger assembly is put into a sintering furnace to be sintered, the plunger lining and the plunger hole are subjected to diffusion welding, and the plunger pump cylinder body is obtained after cooling. According to the method, the plunger bushing is placed in the ultralow-temperature environment to be shrunk, mechanical press fitting is easier, then diffusion welding is combined, metallurgical bonding between the copper alloy bushing and the steel base body is achieved, and the service life of materials is prolonged.

The invention provides a red copper connector and a diffusion welding method thereof, and relates to the technical field of metal welding, the diffusion welding method of the red copper connector comprises the following steps: taking a red copper base material, and performing nanocrystallization treatment on one side surface of the red copper base material through an ion impact method to form a welding surface; the annealed copper middle layer is placed between the two pieces of red copper base metal, the annealed copper middle layer makes contact with the welding face, and a connector to be welded is formed; and the connector to be welded is welded through a pulse current auxiliary diffusion welding method, the red copper connector is obtained, the welding temperature of the pulse current auxiliary diffusion welding method is 300 + / -5 DEG C, the pressure is 18-22 MPa, and the heat preservation time is 25-35 min. And low-temperature, rapid and small-deformation reliable connection of the red copper base metal is achieved.

The invention discloses a titanium-based interlayer for titanium-aluminum series dissimilar alloy diffusion welding and a preparation method and application of the titanium-based interlayer, and belongs to the field of dissimilar metal diffusion welding. The middle layer is prepared from the following components in percentage by mass: 72.7%-83.1% of Ti, 13.5%-14.8% of Mo and 2.1%-13.8% of Ta, and the sum of the mass percentages of all the components is 100%. According to the method, the oxidation resistance of the diffusion welding head is remarkably improved while the welding quality and precision are guaranteed, high-quality and high-performance diffusion welding of the TiAl / Ti2AlNb composite component is achieved, and the design index and use reliability requirements are met.

The invention provides a PCHE core based on gradually-shrunk and gradually-expanded channels and a preparation method of the PCHE core, and belongs to the technical field of heat exchange equipment, the PCHE core specifically comprises heat exchange plates, the heat exchange plates are provided with semi-oval channels, the semi-oval channels on the two heat exchange plates are oppositely arranged to form an oval channel, the multiple oval channels are arranged in a stacked mode, and the heat exchange plates are arranged in the oval channel. The elliptical channels for circulating the hot fluid and the elliptical channels for circulating the cold fluid are alternately arranged; an inner inserting piece is arranged in the oval channel, one opposite side wall of the inner inserting piece is connected with the side wall, in the short axis direction, of the oval channel, and a periodic gradually-shrinking and gradually-expanding channel is formed between the remaining side wall of the inner inserting piece and the remaining side wall of the oval channel. An elliptical channel is prepared by chemical etching, and an interposer is fixed in the elliptical channel by diffusion welding technology to form a tapered and divergent channel. According to the treatment scheme, the heat exchange efficiency and the precision and consistency of the structure are improved, and the manufacturing process is simplified.

The invention discloses a method for connecting a skutterudite thermoelectric material and an electrode by using a high-entropy alloy and low-expansion-coefficient particle composite barrier layer, and relates to a method for connecting the skutterudite thermoelectric material and the electrode. The method aims at solving the problems that an existing conductive connector for connecting a skutterudite thermoelectric material and an electrode through a barrier layer is large in thermal stress and prone to cracking. The method comprises the steps that composite powder of high-entropy alloy and low-expansion-coefficient particles is prepared through a mechanical mixing method; and preparing the high-entropy alloy and low-thermal-expansion-coefficient particle composite barrier layer by adopting a sintering method. And then the barrier layer, the skutterudite thermoelectric material and the electrode are connected into a conductive joint through a diffusion welding or brazing method. The materials of the low-expansion-coefficient reinforced particles comprise but are not limited to low-expansion metal particles, graphite and the like; the components of the high-entropy alloy matrix material comprise, but are not limited to, an Al-Co-Cr-Fe-Ni system, an Fe-Co-Ni-Cu system, an Hf-Nb-Ta-Ti-Zr system and the like. The skutterudite thermoelectric material and the electrode are connected through the composite barrier layer of the high-entropy alloy and the low-expansion-coefficient particles, and the obtained conductive connector has high mechanical strength, a low-resistance interface and excellent thermal stability at the same time. The method is suitable for connecting the skutterudite thermoelectric material and the electrode.

The invention discloses a preparation method of a composite interlayer suitable for nickel-based alloy TLP connection, belongs to the field of diffusion welding, and comprises an atomization powder preparation process, a ball milling process and a cold isostatic pressing forming process. AuSi powder is prepared through an atomization powder preparation process, then the AuSi powder and NiTi powder are mixed through a ball milling process, and finally a composite intermediate layer blank is obtained through cold isostatic pressing. According to the method, the AuSi composite middle layer is prepared through the powder metallurgy process, the distribution uniformity of NiTi particles in an AuSi matrix is improved, and the problems that AuSi eutectic structure residues exist in a welding seam and solidification hot cracks appear in the welding seam due to uneven distribution of the NiTi particles are solved. The mass ratio of AuSi powder and NiTi powder capable of completely reacting is accurately calculated through a chemical reaction formula, the adding amount of NiTi particles is accurately controlled through a mechanical ball milling technology, and the problem that in the welding process, excessive Ti elements easily react with Au elements to form a brittle Au4Ti compound is solved.

The invention discloses a manufacturing method of a light-weight brake disc for a new energy automobile. The manufacturing method comprises the following steps that firstly, an alloy steel layer and a mold are machined according to the size of an aluminum alloy brake disc; secondly, plasma activating treatment is conducted on the friction face of the aluminum alloy brake disc and the face to be welded of the alloy steel layer; and thirdly, the aluminum alloy brake disc and the alloy steel layer are put into a mold in a vacuum clean environment, the friction face makes contact with the face to be welded, and then vacuum diffusion welding is conducted. According to the manufacturing method, the alloy steel layer is welded on the friction surface of the aluminum alloy brake disc, so that the wear rate is reduced on the basis of keeping light weight, and the service life of the aluminum alloy brake disc is prolonged; meanwhile, the aluminum alloy brake disc and the alloy steel layer are pretreated through plasma activation, so that more sufficient and more uniform atomic-scale combination of the aluminum alloy and the alloy steel is achieved in vacuum diffusion welding, and the method is suitable for the field of automobile brake disc preparation.

The invention discloses a Ti-Al-Mo-Ta-Cr multi-element interlayer for diffusion welding of titanium-aluminum series dissimilar alloys and application of the Ti-Al-Mo-Ta-Cr multi-element interlayer, and belongs to the field of diffusion welding of dissimilar metals. The middle layer is prepared from the following components in percentage by mass: 68.31 percent to 73.64 percent of Ti, 14.78 percent to 14.90 percent of Mo, 6.50 percent to 6.54 percent of Ta, 4.82 percent to 4.84 percent of Al and 0.13 percent to 5.54 percent of Cr, and the sum of the mass percent of all the components is 100 percent. According to the Ti-Mo-Ta-Al-Cr five-element interlayer alloy disclosed by the invention, the oxidation resistance of a diffusion welding joint can be effectively improved.