293 results about "Residual compressive stress" patented technology

The invention discloses a method for improving the high-cycle fatigue performance of a Ti6Al4V titanium alloy, and belongs to the technical field of metal material processing, and the method comprises the following steps: S1, determining shot peening strengthening parameters based on material performance parameters and related standards; according to the method, high-amplitude residual compressive stress is introduced through shot peening strengthening, the stress state of the surface and the depth direction of the material is changed, accordingly, crack extension can be restrained, the fatigue life is prolonged, in addition, a plastic deformation layer is induced to be generated under the surface depth in the shot peening process, the microstructure of the material is improved, and the anti-fatigue performance of the material is improved; through femtosecond laser shock, surface defects can be effectively removed, the surface compactness can be improved, microcracks can be reduced, and a refined grain structure can be generated, so that the strength and toughness of the material are further enhanced, the high-cycle fatigue performance of the material is further improved, the two are combined, the residual stress state is optimized, and the surface integrity is improved. The fatigue performance of the Ti6Al4V titanium alloy is remarkably improved.

The invention belongs to the technical field of metal part surface modification, and relates to a composite strengthening method for a carburized surface of a high-bearing gear of an aero-engine. According to the method, high-hardness and high-density ceramic shots are adopted as media for high-energy mechanical shot peening strengthening, the advantage that the subsurface strain hardening effect of the contact strengthening technology is good and the barb-shaped distribution characteristic of mechanical shot peening residual compressive stress are utilized, extremely high residual compressive stress is introduced to the subsurface position, and the contact fatigue performance of the tooth surface of the gear is improved. High-frequency laser shot peening strengthening is used for secondary treatment, so that the surface layer of the material is subjected to plastic deformation, high-amplitude residual compressive stress is introduced into the surface layer of the material within the depth range of more than 500 microns by utilizing the advantage of large influence depth of laser-induced shock waves, and the residual compressive stress can inhibit fatigue crack initiation, has a certain depth and inhibits fatigue crack propagation; and the bending fatigue resistance of the root of the gear can be effectively improved. And an abrasive flow process is adopted, so that the roughness is reduced to be more than 0.4 mu m.

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 laser-assisted composite ultrasonic strengthening treatment of a titanium alloy, a product and application, and belongs to the technical field of metal material surface treatment.The method comprises the following steps that a composite gradient nanometer strengthening layer is prepared on the surface of the titanium alloy by combining laser with an ultrasonic nanometer surface modification and ultrasonic surface rolling treatment technology. The invention further provides the titanium alloy prepared through the method and application of the titanium alloy in the aviation field. According to the LA-UNSM + USRP technology, the surface damage of the titanium alloy is reduced, a stable composite gradient nanometer strengthening layer and a residual compressive stress field are provided, and the purpose of continuously and effectively improving the high-temperature fretting fatigue performance of the titanium alloy in the high-temperature fretting fatigue process of the titanium alloy can be achieved.

The invention belongs to the technical field of surface strengthening, and particularly relates to an aluminum alloy friction stir welding seam fatigue-free method based on rolling strengthening. The method comprises the following steps: (1) carrying out a microhardness test and a tensile test on an aluminum alloy matrix to obtain the hardness and tensile strength of the matrix; and (2) friction stir welding is conducted. The tensile strength after friction stir welding is not lower than 65% of the fatigue strength of a base body by adjusting friction stir welding process parameters; and (3) the surface of the friction stir welding part is treated. The surface of the welding seam is polished through an angle grinder and abrasive paper, so that the surface roughness of the welding seam reaches about Ra1.2 microns; and (4) rolling surface strengthening is carried out. Surface strengthening process parameters are adjusted, so that the surface hardness of a heat affected zone of the weld joint subjected to surface strengthening is not lower than the surface hardness of a matrix, the surface roughness Ra is not higher than 0.5 mu m, and the surface residual compressive stress is not lower than 100 MPa; and (5) carrying out a fatigue test.

The invention relates to the technical field of wind power equipment output shaft forging, and discloses a wind power equipment output shaft anti-fatigue performance optimization forging process which comprises the following steps that a blank is heated to a preset temperature to improve the forgeability of the blank, and a base is provided for subsequent forging; hot forging is conducted, specifically, a staged forging technology is adopted, grains are refined step by step, and forging defects are removed; cold forging is conducted, specifically, the blank is cooled to the room temperature to be subjected to cold forging treatment for optimizing the surface hardness and toughness of the forge piece, and the anti-fatigue performance is further enhanced; after finish forging and cold forging, residual compressive stress on the surface of the forge piece is treated; the temperature field is heated and detected, in the heating process, the temperature of the blank is detected in real time through temperature detection equipment, the temperature field is calculated, and it is ensured that the temperature is evenly distributed. The blank is subjected to hot forging in stages, grains can be gradually refined, forging defects are eliminated, then cold forging treatment is conducted, the surface hardness and toughness of the forge piece can be further optimized, the anti-fatigue performance is enhanced, and the quality and reliability of the forge piece are 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 discloses a carbon-oxygen corrosion resistant coating powder material and a preparation method of a carbon-oxygen corrosion resistant coating, and belongs to the technical field of advanced materials.The chemical composition of the coating powder material comprises 21-24 wt.% of Cr, 7-10 wt.% of Mo, 3-5 wt.% of Nb, 2-4 wt.% of Co, 1-2 wt.% of W, 0.4-0.7 wt.% of Ti, 0.1-0.3 wt.% of Si, 0.05-0.10 wt.% of B and the balance Ni. The coating powder material forms a coating on the surface of a base body through a laser cladding technology, and the coating is prepared from the carbon-oxygen corrosion resistant coating powder material and the preparation method of the carbon-oxygen corrosion resistant coating. The surface hardness, the corrosion resistance and the wear resistance of the supercritical CO2 hot-end equipment material are greatly improved, the coating and the base material are in metallurgical bonding, the internal structure of the coating is compact, the penetration defect does not exist, the maximum size of the healable microdefect is larger than or equal to 200 microns, and the residual compressive stress is larger than or equal to 800 MPa; the weight gain of a laser deposition layer is smaller than or equal to 0.03 mg / cm < 2 > after 1000 hours in a supercritical CO2 static environment of 650 DEG C / 20 MPa, the weight change of the laser deposition layer is smaller than or equal to 0.05 mg / cm < 2 > after 1000 hours in a high-flow-rate dynamic environment of 10 m / s, and the laser deposition layer can be applied to manufacturing of key parts of energy equipment such as nuclear power equipment.

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 preparation method of microcosmic-macroscopic prestress synergistically enhanced aluminum oxide ceramic and a product of the microcosmic-macroscopic prestress synergistically enhanced aluminum oxide ceramic. Low-shrinkage mineral kyanite particles are utilized on the surface of an aluminum oxide matrix, so that the surface layer of the matrix is subjected to microcosmic compressive stress, and the matrix is strengthened for the first meanwhile, the matrix is secondarily strengthened by wrapping type compact constraint macroscopic compressive stress on the surface layer of the matrix, so that the microcosmic-macroscopic residual compressive stress is synergistically enhanced, and the composite reinforced aluminum oxide ceramic consisting of the aluminum oxide matrix as well as the ion exchange-like layer and the prestressed coating on the surface of the matrix is formed; the breaking strength of the aluminum oxide ceramic is obviously improved, and the service life 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 post-treatment method of an additive manufacturing metal part, and aims to solve the problem of insufficient fatigue performance caused by large surface roughness, internal residual tensile stress and the like of the additive manufacturing metal part. The fatigue weak part of the part can be directly subjected to high-frequency scanning treatment by using a micro-scale laser shock peening method under the conditions of no absorption protection layer, no water-light coaxial restraint layer and the like, and the surface roughness is reduced through the direct ablation melting effect of micro-scale small-energy pulse laser and the surface of the part; residual compressive stress is formed on the surface layer of the part through the mechanical effect of laser-induced shock waves, the surface smoothness is improved, the fatigue performance is improved, a laser melting / heat affected layer is removed through sand blasting, the surface smoothness is further improved, and therefore rapid post-treatment of the additive manufacturing metal part is achieved, and the method can be directly applied to engineering.

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 belongs to the technical field of advanced manufacturing, and particularly relates to a method for improving the fatigue performance of an additive structure. The method comprises the steps that the surface of a metal part for additive manufacturing is cleaned, and residual metal powder in the additive manufacturing process is removed; residual compressive stress is introduced to the surface of the part, the introduction process of the residual compressive stress is performed once or multiple times, and the compressive stress level can be adjusted according to the performance requirement of the part in the multiple-time introduction process; the part is placed in a high-temperature environment protected by vacuum or inert gas to be subjected to heat treatment; the residual compressive stress is introduced again, heat treatment is not carried out any more, and the strength of the residual compressive stress reaches the highest fatigue performance level of the material; and surface vibration finishing treatment is adopted, so that the surface roughness of the part is reduced. According to the method, the grain size of the surface of the structure is refined through a combination method, meanwhile, residual compressive stress is introduced between the surface and the subsurface of the part in a combined mode, and the fatigue resistance of the additive manufacturing part is improved by 30 MPa or above.

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 provides a shot blasting method for strengthening the surface of a gear. The shot blasting method mainly comprises the following steps: step 1, determining basic parameters of a gear material and dividing a blasted material area; 2, calculating the shot blasting surface coverage rate based on shot blasting parameters such as the shot size, the crater diameter and the shot number; step 3, randomly generating and calculating the spatial position of the multi-shot peening shot; and 4, shot peening strengthening parameter design with the gear surface roughness and the residual compressive stress as targets is carried out. According to the method, the gear roughness and residual stress calculation method is combined, the influence of various shot blasting parameters on the surface strengthening integrity of the gear is analyzed, the tooth surface performance of the gear is improved, and the fatigue life of the gear is prolonged.

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 invention provides a ball bearing fatigue life calculation method considering residual stress distribution, and the method comprises the steps: building a rolling bearing contact nonlinear finite element analysis model considering a bearing ring surface residual stress factor, and enabling the model to fully consider ring deformation and actual boundary conditions; the influence rule of the residual compressive stress on the surface of the bearing ring on the load and life of the rolling body is analyzed, and the calculation precision of the fatigue life of the ball bearing is greatly improved. Therefore, the fatigue life of the bearing can be prolonged by applying certain residual compressive stress to the bearing ring, the problem of prolonging the service life of the thin-wall angular contact ball bearing is solved, and the actual service life of the thin-wall angular contact ball bearing is prolonged. The depth and direction of the maximum shear stress of the bearing ring are extracted by utilizing a Perma finite element result, and on the basis, the service life of the angular contact ball bearing is further optimized, so that the service life of the bearing is prolonged, and the economic benefit and the social benefit are very huge.

The invention belongs to the field of composite material residual stress detection, and particularly relates to a method for testing residual stress of a laying process SiCf / SiC composite material matrix, which comprises the following steps of: preparing a SiCf / SiC composite material flat plate with a laying layer of [(90-degree) 3 / (0-degree) 6 / (90-degree) 3] by adopting a prepreg-infiltration process, and then cutting a straight strip sample on the flat plate; the method comprises the following steps: designing samples with a specific layering sequence by utilizing a distribution rule of residual stress in 0-degree layering and 90-degree layering of a layering composite material, and acquiring a laminate material modulus EX, a material modulus E0 in a 0-degree direction and a material modulus E90 in a 90-degree direction by utilizing different samples; and finally, calculating the residual compressive stress of the matrix by utilizing a residual stress theoretical formula based on a beam theory. According to the test scheme designed by the invention, the relationship between the residual stress and the bending curvature is established based on the beam theory of the composite laminate, and a plurality of modulus parameters of the material and the interlayer fracture toughness of the material can be obtained in the test process of the residual stress.

A machining method for improving residual compressive stress of a raceway surface of a bearing ring relates to the technical field of bearing machining and comprises the following steps: turning a bearing ring blank, and then quenching and tempering a machined part; the surface of the ferrule raceway subjected to heat treatment is subjected to shot blasting machining strengthening; carrying out primary grinding processing on the surface of the reinforced ring raceway, and then carrying out additional tempering treatment; the surface of the ring raceway is subjected to fine grinding, and then the surface of the ring raceway is subjected to final grinding; and carrying out superfinishing on the surface of the ring raceway. According to the method, a machining procedure mutual matching strategy is adopted, the machining technological process is optimized, machining parameters of all procedures are strictly controlled in the machining process, through progressive machining of all the procedures, the surface residual compressive stress of the bearing ring raceway is gradually increased, good control over the residual compressive stress scattering difference is achieved, and the fatigue life of the bearing can be effectively prolonged. The residual compressive stress on the surface of the bearing ring raceway machined through the method is not smaller than 515 MPa, and the residual compressive stress range is not larger than 68 MPa.

A piston ring includes a substrate, and a film covering at least a part of a surface of the substrate. The film includes Si and N. A Si content of the film is in a range of 1.1 to 7.5 at %, a crystallite size of the film is in a range of 10 to 30 nm, and a compressive residual stress of the film is 400 to 800 MPa.

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.