226 results about "Residual compressive stress" patented technology

The invention discloses a preparation method of a super hydrogen embrittlement-resistant carbon steel material based on laser surface treatment, which comprises the following steps: carrying out surface pretreatment on a carbon steel substrate, and carrying out surface pretreatment including sand blasting treatment, ultrasonic cleaning and preheating treatment; laser cladding equipment is adopted to synchronously convey alloy powder on the surface of the pretreated carbon steel matrix for alloying treatment, and an alloying layer containing carbide is formed; the laser power and the scanning speed are adjusted to conduct gradient treatment on the alloying layer, and a gradient transition layer from the surface layer to the base body is constructed; performing laser shock peening treatment on the gradient transition layer to generate a shock peening layer; step type annealing treatment is conducted on the base body obtained after impact strengthening, and the component content is monitored in real time; through the synergistic effect of the gradient alloying layer and the impact strengthening layer, a carbide hydrogen barrier and a residual compressive stress protection layer are formed on the surface layer of the material, so that the hydrogen diffusion coefficient is reduced; the gradient transition structure effectively relieves interface stress concentration, and the hydrogen embrittlement resistance of the carbon steel material is improved.

The invention discloses a method for improving obdurability matching of titanium alloy by inducing an FCC phase through high-temperature impact deformation, and belongs to the technical field of metal material phase change regulation and control. The method comprises the steps that after annealing treatment and surface treatment are conducted on a substrate material, the substrate material is sequentially covered with a sacrificial layer and a restraint layer and evenly pressed, the substrate material is placed on a heating table of a high-temperature impact deformation device to be preheated, and the substrate material is subjected to high-temperature impact deformation; according to the method, the energy required for transformation of the HCP phase to the FCC phase is reduced, the heating temperature and laser shock parameters are set, the HCP phase is induced to be transformed into the FCC phase under the dynamic stress-temperature synergistic effect through multi-pass laser shock peening and high-temperature and high-speed shock deformation, the FCC phase, nano twin crystals and residual compressive stress form the synergistic peening effect, and therefore the HCP phase is converted into the FCC phase. Further, the grain refinement process is accelerated, the strength and plasticity matching is improved, and the high-temperature impact deformation induces the FCC phase to improve the strength and toughness matching of the titanium alloy; the substrate is made of industrial pure titanium or titanium alloy. The method is suitable for high-strength parts with complex geometrical shapes, is more widely applicable than traditional rolling annealing, and provides reference for strengthening and toughening of titanium alloy.

The invention provides a method for preparing a honeycomb sandwich structure based on laser collaborative explosive welding, and belongs to the technical field of explosive welding. The method comprises the following steps: carrying out laser pretreatment on the surface of a honeycomb core to form a periodically distributed micron-sized pit array; submicron-order holes are constructed in the micron-order pit array based on a nanoimprint lithography method; covering the surface of the plane material with an energetic material layer, and carrying out explosive welding on the plane material and the pretreated honeycomb core by utilizing shock waves generated after the energetic material layer is detonated to obtain a honeycomb sandwich structure; the laser pretreatment adopts femtosecond laser treatment, the power density is 106W / cm < 2 >-107W / cm < 2 >, the pulse width is 100fs-500fs, and the distance between scanning paths is 10mu m-50mu m. According to the method, a metallurgical bonding layer and a residual compressive stress field are formed on the connection interface of the honeycomb core and the plane material through the synergistic effect of laser pretreatment, nanoimprint and explosive welding, crack propagation is inhibited, the fatigue life of a joint is prolonged, and thermal damage is reduced.

The invention relates to the field of aircraft hydraulic control element machining, and particularly discloses an aircraft hydraulic kinematic pair valve element lubricating structure laser surface texturing method which comprises the steps of lubricating spherical crown texture design, texturing machining path, protection cleaning, laser parameter testing, laser machining pretreatment, test piece texturing and texturing effect inspection. Machining of the micro-nano structure on the surface of the valve element of the hydraulic kinematic pair of the airplane is achieved through high-energy and short-pulse femtosecond laser, machining precision is high, controllability is high, environmental pollution is small, and compared with the prior art, abrasion of the matching face of the valve element and the cylinder sleeve kinematic pair can be reduced to a great extent; and meanwhile, high-pressure shock waves induced by femtosecond laser are utilized to form residual compressive stress on the surface of the valve element, so that oil and scrap storage and surface lubrication wear resistance of the surface of the valve element are synergistically improved, and the overall service life of the aircraft hydraulic control element is prolonged.

The invention discloses a method for improving the oxidation resistance of nickel-based superalloy, and belongs to the technical field of metal material surface modification. Based on the high-energy transient effect of laser shock waves, the method mainly comprises the key steps of alloy surface pretreatment, laser shock peening process implementation, post-treatment and the like. Specifically, firstly, the surface of the nickel-based single crystal alloy is subjected to pretreatment such as polishing and cleaning, surface defects and pollutants are removed, and the treatment quality is guaranteed; then, according to the material characteristics and performance requirements of the nickel-based single crystal alloy, laser parameters such as laser energy, pulse width and light spot diameter are accurately set, and proper restraint layer and absorption layer materials are selected; then, high-energy pulse laser is utilized to irradiate the absorption layer, high-temperature and high-pressure plasma is induced to be generated, the plasma expands and explodes to generate strong shock waves, the shock waves act on the alloy surface, the surface material is subjected to severe plastic deformation, a residual compressive stress layer with the depth capable of reaching hundreds of micrometers is formed, meanwhile, surface grains are refined, and the microstructure is optimized; and after the strengthening treatment is completed, simple cleaning and performance detection post-treatment are carried out. Through laser shock strengthening, a special organization structure with high density and low defect density is formed on the surface of the nickel-based single crystal alloy, diffusion and invasion of oxygen atoms are effectively hindered, and the oxidation resistance of the alloy is remarkably improved. According to the method, the controllability of technological parameters is high, the strengthening effect can be accurately regulated and controlled, the treatment process is free of pollution and high in efficiency, the obtained strengthened nickel-based single crystal alloy can be widely applied to the fields such as aerospace engine hot end parts and nuclear energy equipment which have strict requirements for high-temperature oxidation resistance, the reliability of related parts is greatly improved, and the service life of the related parts is greatly prolonged.

The invention discloses a high-wear-resistance hard alloy CVD (Chemical Vapor Deposition) coated cutting tool and a preparation method thereof, WC-Co (4-8) Ti (1-5) Ta (1-5) Nb (0.2-2) Cr (0.2-2) Fe (0.2-2) Al (0.2-2) is used as a blade substrate, TiN, TiCN, Al2O3 and a surface TiN coating are deposited firstly, and then the coated blade is subjected to subzero treatment and tempering treatment. According to the method, through subzero treatment between the base body and the coating, the compressive stress is introduced into the coating or an interface by utilizing the difference of the extremely low temperature shrinkage rates of the coating and the base body, the tensile stress caused by the compressive stress neutralization deposition is utilized, and the uniform distribution of nanoscale carbide precipitates is promoted by utilizing a proper tempering process; and the cold brittleness phenomenon caused by subzero treatment and the generated high residual compressive stress are avoided, and the abrasion resistance and the anti-stripping capacity of the base body are further improved. According to the method, the driving effect of residual tensile stress in the CVD coating on crack initiation is reduced, the crack density is greatly reduced, the mechanical property of a hard alloy matrix and the stress state of the coating are synergistically improved, and the mechanical property of the cutter is enhanced.

The invention relates to a shot peening method for strengthening the mechanical property of a laser additive manufacturing titanium-based composite material, which comprises the following steps of: performing single-pass shot peening on the surface of the titanium-based composite material under the conditions that the air pressure is 0.1-0.25 MPa and the shot peening time is 3-10 minutes, and removing residual shots on the surface of the titanium-based composite material after the shot peening is finished, the tensile strength of the reinforced titanium-based composite material at the room temperature is improved by 50-100 MPa from 1152.76 MPa in an initial printing state. According to the shot blasting treatment provided by the invention, residual compressive stress is introduced by bombarding the metal surface through small particles, the surface structure is subjected to plastic deformation, grains on the outermost surface are remarkably refined, and the mechanical property of the titanium-based composite material manufactured by laser additive manufacturing is effectively improved at low cost.

The invention provides a metal material surface treatment method based on the synergistic effect of solid solution-aging heat treatment and laser shock. The metal material surface treatment method is used for remarkably improving the mechanical property of a metal material and the uniformity and stability of a microstructure. Different from a traditional single laser shock peening process, the heat treatment method is combined with laser shock, and the double effects of structure optimization and mechanical property enhancement are achieved. Specifically, firstly, alloy elements are subjected to sufficient solid solution in a matrix through solid solution-aging heat treatment, heat preservation is conducted at the low temperature so that a strengthening phase can be promoted to be separated out again, and the strengthening phase which is evenly and stably distributed is obtained; and then laser shock is applied to the surface of the material, deep residual compressive stress is introduced into the surface layer through high-energy pulse laser, and a nanocrystalline layer structure is formed. According to the synergistic process, the microstructure stability and uniformity of the material are effectively improved, and the mechanical property of the material is remarkably improved. The technology is suitable for the fields of aerospace, automobile lightweight structures, rail transit and the like, and has wide industrial application prospects.

The invention discloses a method for improving the rotating bending fatigue strength of an AlCoCrFeNi 2.1 eutectic high-entropy alloy, and belongs to the technical field of alloys. According to the method, the AlCoCrFeNi 2.1 eutectic high-entropy alloy is treated by utilizing an ultrasonic surface rolling process (USRP), so that the density of surface defects and holes of the AlCoCrFeNi 2.1 eutectic high-entropy alloy is effectively reduced, and the rotating bending fatigue strength of the AlCoCrFeNi 2.1 eutectic high-entropy alloy is improved. And meanwhile, the surface roughness is reduced, the surface structure morphology is changed, the crack propagation path is prolonged, and finally the purpose of improving the fatigue performance of the AlCoCrFeNi 2.1 eutectic high-entropy alloy is achieved. According to the method, the surface structure of the AlCoCrFeNi 2.1 eutectic high-entropy alloy can generate residual compressive stress under the action of high-frequency vibration and static-load rolling of the USRP, so that the initiation time of fatigue cracks is effectively prolonged, and the fatigue performance of the AlCoCrFeNi 2.1 eutectic high-entropy alloy is enhanced.

The invention relates to the technical field of motor clamp springs, and particularly discloses a high-strength ultrathin titanium alloy for a motor clamp spring and a preparation method thereof.The preparation method comprises the steps that firstly, a titanium alloy cast ingot is subjected to hot forging machining, coarse and large crystal grains are crushed, then hot rolling is conducted, and in the hot rolling process, pulse current is adopted for assisting, and the high-strength ultrathin titanium alloy is obtained through the electroplastic effect; the method comprises the following steps: carrying out hot rolling to obtain a grain structure finer and more uniform than traditional hot rolling, then carrying out shot blasting treatment and carbonitriding treatment on the surface of a titanium alloy matrix to enhance the hardness, strength, wear resistance and fatigue resistance of the material, and finally, introducing a residual compressive stress field while eliminating surface defects and increasing surface compactness by adopting a heat-assisted ultrasonic rolling process, so as to improve the wear resistance of the material. The generation and expansion of fatigue microcracks are inhibited, and the anti-fatigue performance of the material is enhanced.

The invention discloses a heavy axle rolling method based on rolling differentiation, which comprises the following steps: S1, axle pretreatment: adopting a two-stage cleaning process, firstly performing high-pressure flushing through kerosene at 60-80 DEG C, then performing double-frequency alternate ultrasonic cleaning, and drying with hot air at 70 DEG C after cleaning, so that the surface roughness Ra of the pretreated axle is less than or equal to 1.6 mu m, and the oil stain residual quantity is less than or equal to 5mg / m < 2 >; s2, three-dimensional modeling and stress partitioning are carried out, an axle digital model is established, and stress simulation is carried out. According to the method, a plastic deformation layer of 0.2 mm-0. 3mm and a residual compressive stress field of which the depth is greater than or equal to 0.5 mm are formed on the surface layer aiming at reinforced rolling of a high-stress area, and the range value is-200MPa to-300MPa, so that the tensile stress in the working process is effectively counteracted, the fatigue life of the axle is prolonged, and the service life of the axle is prolonged. According to the stepped rolling technology, surface defects are eliminated through pre-rolling, a uniform strengthened layer is formed through main rolling, the surface quality is optimized through fine rolling, the overall impact resistance of the axle is improved, and the axle can adapt to the severe working condition of long-term heavy-load running of heavy vehicles.

The present invention provides a mechanical strengthening device and method for the raceway surface of a rolling bearing ring, belonging to the field of surface mechanical strengthening. The strengthening device includes a numerical control machine tool body, and also includes a clamping assembly and a strengthening tool assembly. The clamping assembly is used to form circumferential positioning on the inner circumferential wall of the inner ring of the rolling bearing or the outer circumferential wall of the outer ring and is detachably connected to the rotary output structure. The strengthening tool assembly includes a tool holder and a strengthening tool. The strengthening tool is connected to the tool feed structure of the numerical control machine tool body. The strengthening tool is used to contact and roll over the raceway of the inner ring or the outer ring so that local plastic deformation occurs on the raceway surface, generating dislocations and refining grains to form a strengthened layer with residual compressive stress. The device structure and implementation process of the present invention are simple. Since the rolling and pressing method is used to cause plastic deformation on the raceway surface, generating dislocations and refining grains to form a strengthened layer with residual compressive stress, no dust is generated during the processing, and no chips are produced either, which is clean and environmentally friendly.

The invention belongs to the technical field of mechanical manufacturing and material science, and particularly relates to an artificial intelligence chip inductor powder mold surface strengthening treatment method and system, which comprises the steps of mold matrix mechanical shock strengthening pretreatment, preparation of a gradient diffusion layer, a toughness bonding layer and a superhard wear-resistant layer in sequence without breaking vacuum, and post-treatment. The system is integrated vacuum treatment equipment and realizes continuous treatment without breaking vacuum. Surface mechanical shock strengthening is introduced in the pretreatment stage of a mold base body, and a strengthening layer with a fine grain structure, high-density dislocation and remarkable residual compressive stress is formed on the surface layer of the mold. According to the strengthening layer, the fatigue strength and the plastic deformation resistance of the mold base body are effectively improved, a tough bearing substrate is provided for growth of the subsequent surface strengthening layer, and therefore the problem that the binding force between a traditional strengthening layer and a brittle base body is insufficient is fundamentally solved, and the fatigue fracture resistance of the whole mold structure is remarkably improved.

The invention discloses an ultrafast laser strengthening method for improving the vibration fatigue life of titanium alloy, and belongs to the technical field of metal material surface strengthening. The method comprises the following steps: S1, carrying out surface cleaning treatment on a titanium alloy material; s2, carrying out laser strengthening treatment on the surface of the metal material by using ultrafast laser; s3, ABAQUS software is adopted to simulate stress and displacement of the titanium alloy simulation part under the first-order vibration frequency; s4, carrying out a vibration fatigue test, and comparing the vibration fatigue life of the titanium alloy simulation part before and after reinforcement; according to the ultrafast laser strengthening method, ultrahigh-pressure shock wave pressure is generated on the surface of the metal material through induction of ultrafast laser, then a gradient residual compressive stress layer, finer crystal grains and higher dislocation density are formed on the near surface of the metal material, and the vibration fatigue life is prolonged by inhibiting crack initiation; the ultrafast laser strengthening method is high in feasibility and good in strengthening effect and has high application and popularization value.

The invention is applicable to the field of laser strengthening, and provides a laser strengthening method for regulating and controlling the surface performance of an additive part of a combustion chamber, which comprises the following steps: S1, pretreatment: sequentially performing stress relief annealing, surface cleaning, cleaning and drying on a metal part of the additive combustion chamber; s2, coating-free laser shock peening is conducted, specifically, the pretreated part is fixed to a five-axis workbench through a special clamp to be positioned, and Nd: YAG or Nd: YLF pulse laser is adopted for shock according to a path planned by a three-dimensional CAD model; s3, post-treatment and performance verification are conducted, specifically, after the part is cleaned, the surface appearance, roughness, residual stress and microhardness are detected, and a microstructure is observed; according to the method, the coating procedure of traditional laser shock is omitted, the pollution risk is eliminated, the surface roughness is synchronously reduced, the deep residual compressive stress is introduced, the microhardness is improved, the fatigue resistance of the combustion chamber component is remarkably improved, and the method is suitable for materials such as nickel-based high-temperature alloy and cobalt-based high-temperature alloy and components of complex structures.

A method for manufacturing high-strength, hydrogen-embrittlement-resistant bolts based on microsphere shot peening, and the bolts themselves, are disclosed. The manufacturing method includes: S1, cold heading and thread rolling of alloy structural steel billets to obtain bolt forming parts; S2, surface cleaning of the bolt forming parts, followed by overall surface peening with microspheres driven by high-pressure air; after overall peening, targeted strengthening peening treatment is performed on stress concentration areas such as thread roots, undercut grooves, and flange transition corners to obtain reinforced bolt parts; S3, the reinforced bolt parts are cleaned, dried, and phosphated to obtain finished bolt parts. This design, through a "overall + targeted" composite microsphere shot peening strategy, introduces a uniform residual compressive stress field and a micron-level fine-grained plastic deformation layer on the bolt surface, forming a thicker strengthening layer in stress concentration areas, significantly improving the fatigue strength and delayed fracture resistance of high-strength bolts, while ensuring uniform surface roughness and stable assembly friction coefficient.

Provided are steel having excellent fatigue strength, a method for producing the steel, and a steel component. The steel has a given composition which satisfies the following relationships (1) and (2), the remainder comprising Fe and unavoidable impurities. The core portion contains a precipitate of one or more of Cr, Mo, V, and Nb. The steel has a surface hardness of 700 HV or greater and a surface compressive residual stress of 750 MPa or greater. (1): ([Mo] / 96+[V] / 50.9+[Nb] / 92.9)×1000≥5.5 (2): ([C] / 12+[N] / 14)×1000≥3.5 In the relationships, [X] is the content (mass%) of element X.

The utility model discloses an anti-fracture lifting table transmission shaft, which relates to the technical field of lifting tables, and comprises a movable component and a fixed component, the bottom end of the movable component and the top end of the fixed component are installed in a sliding manner, and the fixed component comprises a fixed shaft. Meanwhile, a plurality of reinforcing ribs are evenly distributed on the inner wall of the movable shaft in the axial direction, the bending resistance and torsional rigidity of the movable shaft are enhanced, when the transmission shaft is vibrated or impacted, the high-damping filler can absorb energy, reduce the vibration amplitude and improve the stability of the transmission shaft, the movable shaft meets the overall strength requirement, meanwhile, the weight of the shaft is reduced, and the rotational inertia is reduced; and meanwhile, the nitriding layer is additionally arranged on the outer wall of the movable shaft, so that the hardness and the wear resistance of the shaft surface can be improved, residual compressive stress can be generated on the surface, part of tensile stress generated during working is counteracted, the fatigue life of the transmission shaft is further prolonged, and the fracture resistance of the transmission shaft is further improved.

The invention discloses a fatigue crack propagation life prediction method for a laser shock peening titanium alloy lug, and belongs to the technical field of fatigue crack propagation life prediction of a metal structure, and the method comprises the following steps: carrying out laser shock peening on a target lug structure, and testing to obtain a residual stress field of the target lug structure after laser shock peening; carrying out a fatigue test by adopting an identification load method, and interpreting a fracture; stress intensity factors caused by external loads and residual stress of all points of the front edge on the marking line are calculated in finite element numerical simulation software; correcting the fatigue crack growth rate model; calculating a crack propagation amount corresponding to each point of the preset crack front edge based on the fatigue crack propagation rate model, fitting to obtain a new crack front edge, and recording a corresponding cycle index; and calculating to obtain the fatigue crack propagation life. By adopting the method, accurate prediction of the three-dimensional fatigue crack propagation life under the action of the laser shock peening residual compressive stress field is realized.

The invention belongs to the technical field of chains, and particularly relates to a precise chain roller with a smooth surface and abrasion resistance and a preparation method thereof. The invention provides a steel roller which is provided with a DLC final working surface on an excircle mirror surface, an excircle has no texture, and only an inner hole is provided with a micron-sized spiral microgroove. The process is implemented according to the sequence of carburizing / quenching / tempering-shot blasting-fine grinding-superfinishing-vacuum PVD, a diamond-like carbon composite coating is formed on an outer circle, and oil storage and capillary pumping are carried out through control of an outer edge fillet, residual compressive stress and DLC adhesive force and an inner hole microgroove, so that work division of antifriction bearing and oil supply functions is realized. A chain provided with the anti-abrasion precision roller with the smooth surface gives consideration to low friction, low noise and stripping resistance under the boundary lubrication and impact-rolling composite working conditions.

The invention discloses a rectangular flat steel production device, and belongs to the technical field of metal material machining equipment. Comprising a machining unit and an auxiliary unit, multiple sets of machining mechanisms are linearly arranged, synchronous impact or intermittent rhythm impact of multiple sets of driving cylinders is achieved under driving of an external control system, multiple driving cylinder assemblies act on multiple positions of the surface of flat steel at the same frequency and phase at the same time, and large-area synchronous impact machining and simultaneous loading of multiple point positions are achieved; a continuous and consistent residual compressive stress field is formed, stress concentration is reduced, multiple parts are treated at the same time, the method is suitable for continuous machining of a high-speed production line or a large flat steel part, warping and unbalanced internal stress caused by single-point concentrated impact can be reduced through uniform stress distribution, an impact head conducts periodic loading at time intervals, or different positions are impacted in a rhythm alternate mode, and the impact efficiency is improved. A local treatment area is gradually propelled, strengthening treatment such as corners, hole peripheries and heat affected zones can be carried out on specific areas, and the flexibility is improved.

The invention relates to the technical field of metal part machining, in particular to a heavy-duty gear and a preparation method and application thereof. The preparation method of the heavy-duty gear comprises the following steps that S1, intermittent LIS bombardment is conducted on a gear base body; s2, intermittently depositing Cr atoms on the gear base body to obtain a Cr base layer; s3, a CrAlC transition layer and a Cr-Al-GLC layer are sequentially deposited on the Cr base layer; wherein the setting of the working time and the intermittent time of the intermittent LIS bombardment process and the intermittent Cr atom deposition process meets the condition that the temperature of the gear base body is maintained to be 140 DEG C or below. Through intermittent LIS bombardment and intermittent Cr atom deposition processes, the temperature of a gear base body is strictly controlled to be 140 DEG C or below, attenuation of residual compressive stress on the surface of the gear is effectively prevented, the residual compressive stress on the surface (0-25 microns) of the gear is kept at 680-920 MPa, and therefore the contact fatigue strength of the gear is improved, and the service life of the gear is prolonged. And fatigue failure caused by insufficient residual compressive stress of the gear under the heavy load working condition is avoided.

To suppress the occurrence of micro-spalling even in an area shallower than 40 μm from a surface, thereby prolonging a service life of a rolling bearing used in lean lubrication environment in increasingly electrified devices such as an e-Axle and multi-stage automatic transmissions (AT).SOLUTION: A rolling bearing uses a rolling component consisting of a planetary gear 1 corresponding to an outer ring of the rolling bearing, a shaft 2 corresponding to an inner ring, and rolling elements 3, where a micro-Vickers hardness is 800 to 930 Hv0.1 from a surface to a depth of 25 μm, an absolute value of a residual compressive stress on the surface is 850 MPa or more, and a half-width of an X-ray diffraction peak on the surface is 6.0 to 6.7°.SELECTED DRAWING: Figure 2

The present invention provides a method for preparing a honeycomb sandwich structure based on laser-assisted explosive welding, which belongs to the field of explosive welding technology. The method comprises: performing laser pretreatment on the surface of the honeycomb core to form a periodically distributed micron-scale pit array; constructing submicron-scale holes inside the micron-scale pit array based on nanoimprinting; applying an energetic material layer to the surface of the surface material, and utilizing the shock wave generated by the detonation of the energetic material layer to explosively weld the surface material and the pretreated honeycomb core to obtain a honeycomb sandwich structure; laser pretreatment uses femtosecond laser processing with a power density of 10 6 W / cm 2 ~10 7 W / cm 2 The pulse width is 100fs to 500fs, and the scanning path spacing is 10μm to 50μm. This invention utilizes the synergistic effects of laser pretreatment, nanoimprinting, and explosive welding to form a metallurgical bonding layer and residual compressive stress field at the interface between the honeycomb core and the surface material, inhibiting crack propagation, improving joint fatigue life, and reducing thermal damage.

The invention discloses a low-consumption composite surface strengthening method and device and a medium, and relates to the technical field of metal material strengthening. The method comprises the steps that based on the numerical range of multiple cutting parameters, a numerical control machine tool is used for cutting metal materials; and based on the numerical range of various jet parameters, solid projectile inclusion water jet surface strengthening is conducted on the cut metal material through a solid projectile inclusion water jet experiment. Composite surface strengthening is completed through the solid projectile mixed water jet experiment, the surface layer is subjected to plastic deformation while the surface quality of the metal material is improved, residual pressure stress is generated, and then the fatigue life of the material is prolonged.

The invention discloses a treatment process for improving the three-point bending fatigue limit of a thin-wall titanium alloy test piece, and relates to the field of metal material processing for improving the anti-fatigue performance, and the treatment process comprises the following steps: pretreating a TC4 titanium alloy sheet to obtain a test piece; processing the test piece by using ultrafast laser shock peening; setting a load, and respectively carrying out three-point fatigue tests on the test piece before and after strengthening; and calculating the bending fatigue limit of the test piece before and after strengthening, and carrying out strengthening mechanism analysis and comparison. According to the method, a thin-wall TC4 titanium alloy three-point bending test piece can be subjected to impact strengthening by optimizing the combination of femtosecond laser energy and impact times, a gradient structure and residual compressive stress are introduced to a surface layer by utilizing high-strain-rate plastic deformation induced by ultrafast laser, fatigue crack initiation is inhibited, meanwhile, expansion of a heat affected zone and deformation of the test piece are avoided, and the impact strength of the thin-wall TC4 titanium alloy three-point bending test piece is improved. Therefore, the bending fatigue performance is improved.

A method for optimizing forming and performance of a friction stir welding head through pre-welding rolling belongs to the technical field of metal material welding processing, and comprises the following steps: before friction stir welding, a friction stir rolling welding tool is used for carrying out rolling treatment along a to-be-welded welding line path, so that a to-be-welded position is subjected to plastic deformation in advance; residual compressive stress and high-density lattice defects are introduced into the welded joint, so that residual tensile stress generated in formal welding can be effectively counteracted, residual deformation of the welded joint and the structure is reduced, and the mechanical property of the joint can be improved by promoting grain refinement of the weld joint and re-precipitation of a strengthening phase; therefore, synchronous optimization of forming and performance of the friction stir welding joint is realized. Compared with an existing welding method, the method is simple in process, high in repeatability, capable of achieving shape property common control of the large thin-wall welding structure and suitable for high-quality welding manufacturing in the fields of aerospace, rail transit, automobiles, ships and the like.

The present invention discloses a high-entropy composite toughened gradient ceramic tool material and its preparation method and application, belonging to the technical field of ceramic tool materials. It has a symmetrical five-layer structure, which is a surface layer, a transition layer, a core layer, a transition layer and a surface layer in order; by mass, the surface layer includes 85-91 parts of aluminum oxide and 9-15 parts of high-entropy carbide; the transition layer includes 82.8-90.8 parts of aluminum oxide, 6-12 parts of high-entropy carbide, 3-5 parts of zirconium dioxide, and 0.2 parts of graphene; the core layer includes 82-91 parts of aluminum oxide, 3-9 parts of high-entropy carbide, and 6-9 parts of high-entropy alloy. The thermal stress relief and surface residual compressive stress characteristics of the gradient structure are organically combined with the various toughening mechanisms introduced by the high-entropy composite of graphene, and a high-hardness, high-toughness, high-entropy composite toughened gradient ceramic tool material is obtained through liquid phase + solid phase two-step sintering, which significantly improves the adaptability and resistance of the tool to high-speed cutting.

The invention provides a forming process method of an aircraft panel, which comprises the following steps of: firstly, carrying out finite element joint analogue simulation on stretch forming and shot peening strengthening processes before actual operation is started, and determining optimal stretch and low-energy shot peening parameters; after manufacturing is started, a single profile blank is prepared through an integrated extrusion and quenching combined technology, and the defects that in a traditional technology, the rigidity of a multi-component riveting plate is low, and the material utilization rate is low are overcome; in the stretching process, residual tensile stress is introduced into the core part of the wallboard through pre-stretching, and the residual tensile stress and surface residual compressive stress generated by subsequent shot blasting can form a synergistic strengthening effect, so that the fatigue life is prolonged; and shot blasting adopts a low-energy mode, so that various defects caused by traditional high-energy spraying can be effectively avoided while the surface appearance and the pressure stress precision are ensured. The invention also provides targeted process optimization for ribbed and unribbed wallboards, so that not only is the dependence on complex clamping equipment eliminated, but also the deformation risk caused by clamping stress can be effectively avoided.

The invention provides a sectional type arc edge cutter for anti-fatigue machining, and relates to the technical field of cutter machining. Comprising a cutter body, the front end of a cutting edge of the cutter body is provided with a sectional type arc cutting edge so that the flow direction of cuttings of the corresponding arc sections can be changed through arcs between different sections, the cuttings generated during machining can be folded and curled at the different arc sections, the strength of the cuttings is reduced, and the cuttings can be broken off more easily; and a sectional sleeking edge is arranged at the rear end of the sectional arc cutting edge to extrude and rub a machined surface, so that friction vibration of the cutter and a workpiece is reduced, the quality of the machined surface is improved, high residual compressive stress is introduced, and the fatigue resistance of the workpiece is improved. According to the scheme, the cutting strength is reduced at the cutting generation source, the cutting is easier to break, meanwhile, machining vibration caused by a traditional sleeking edge is reduced, and the quality of the machined surface is improved.