29 results about "Severe plastic deformation" patented technology

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.

This invention discloses a two-step oscillating hot-pressing sintering method for WC-Co cemented carbide. Specifically, the method involves: loading WC-Co cemented carbide mixed powder into a mold and pre-pressing it; firstly, holding the powder at 800°C in a vacuum environment to degas and pre-sinter the billet; then applying unidirectional oscillating pressure to the billet through the mold and raising the temperature to 1100°C for solid-state sintering. Dynamic pressure causes WC particles to rearrange, and Co particles undergo severe plastic deformation under the pressure of the WC particles, further increasing the relative density of the billet; finally, the temperature is raised to 1300-1350°C to form a WC-Co eutectic liquid phase. Dynamic pressure drives further particle rearrangement, and the eutectic liquid phase uniformly fills the gaps between WC particles, completing the sintering process. This invention improves the three-dimensional spatial distribution uniformity of the Co phase, eliminates residual porosity, effectively inhibits abnormal growth of WC grains, and produces cemented carbide with excellent strength and toughness.

The application discloses a strain-induced supersaturated solid solution analysis method for a non-miscible alloy system based on mixed entropy evolution, and the method comprises the following steps: for a target A-B binary alloy, a mixed entropy-component relationship diagram of the target A-B binary alloy is drawn; the average component and the initial equilibrium phase component point of the target A-B binary alloy are calibrated in the diagram; based on the increase of the mixed degree of the entropy generation driving force, the two-phase components are predicted to evolve in the entropy increase direction during a severe plastic deformation process, until a single-phase supersaturated solid solution is formed. Based on the irreversible thermodynamic principle, the severe plastic deformation process is defined as a continuous external entropy generation source for driving the evolution of the system, through the analysis of the dynamic competition mechanism of element mixing and element demixing dominated by the entropy generation source, the formation mechanism of the supersaturated solid solution is revealed, and the application provides a universal theoretical tool for understanding and predicting the supersaturated solid solution behavior of the non-miscible alloy system under the severe plastic deformation.

The application discloses a kind of metal surface nanocrystalline preparation method and application based on controllable fretting friction, belong to material preparation technical field.The method is first to the surface of metal sample pretreatment, subsequently it is placed in fretting friction testing machine, by controlling normal load, displacement amplitude, frequency, time and environmental temperature etc.Parameter, make the pair of mating and sample surface occur fretting friction.The core is, utilize the local transient temperature rise generated in the process of fretting friction, make metal surface layer occur dynamic recrystallization while severe plastic deformation, to form nanocrystalline layer in one step, without secondary heat treatment.The application solves the problems such as long process, high energy consumption and difficult to control surface quality of traditional surface nanocrystallization technology, can prepare the uniform nanocrystalline layer with surface grain size in 200-1200nm and layer thickness in 2-30μm range, significantly improve the corrosion resistance of metal material, and process is simple, controllability is strong, and widely applicable material.

The invention relates to a high-strength and ultralow-magnetic susceptibility Au-Pt-Pd alloy wire as well as a preparation method and application thereof, and relates to the technical field of new materials. According to the preparation method, through the unique process combination of smelting, homogenization, severe plastic deformation and specific aging, the problem of contradiction between the alloy strength and the ultralow magnetic susceptibility is successfully solved, and the prepared Au-Pt-Pd alloy wire has the strength and the ultralow magnetic susceptibility far higher than those of a traditional Au-Pt alloy and still keeps certain plasticity.

The present application belongs to the technical field of plastic processing of thin-walled aluminum alloy products, and relates to an aluminum alloy seamless gas cylinder and a manufacturing method thereof. The gas cylinder is formed by a cylinder mouth side half cylinder and a cylinder bottom side half cylinder through seamless inertia friction welding. The cylinder mouth side half cylinder and the cylinder bottom side half cylinder are both prepared by performing severe plastic deformation on an aluminum alloy cylinder body at room temperature through a low-temperature high-pressure torsion device. The shoulder and / or bottom curve surface of the cylinder is formed by layer-by-layer crystallization refinement of metal under high pressure, and a uniform nano-scale or sub-micron ultra-fine grain structure is formed in the material. The present application solves the problems of wrinkle, stacking and high scrap rate caused by difficult temperature control in the traditional hot closing process by performing layer-by-layer severe plastic deformation on the aluminum alloy cylinder body at room temperature through a low-temperature high-pressure torsion process, thereby greatly improving the forming quality and mechanical reliability of the gas cylinder.

The invention discloses a preparation method of a fine-grain high-hardness high-flatness copper plate, which comprises the following steps: (1) sequentially cleaning and polishing a high-purity oxygen-free copper plate to obtain a pre-rolled plate; (2) stacking a plurality of pre-rolled plates, fixing the edges of the pre-rolled plates, and performing multi-pass rolling at room temperature to realize accumulative ply rolling, so as to obtain rolled plates; (3) carrying out annealing treatment on the rolled plate in an inert atmosphere, and then straightening; (4) the annealed plate is subjected to laser surface melting treatment; and (5) surface chemical mechanical polishing and cleaning are carried out, and the fine-grain high-hardness high-flatness copper plate is obtained. According to the method, the copper plate is subjected to severe plastic deformation through the accumulative roll bonding technology, the refining limit of a traditional machining mode on the grain size is broken through through the large dependent variable, then through laser surface melting, the grain size of the surface of the copper plate is further reduced, meanwhile, the surface hardness is increased to 120-190 HV from 50-60 HV, the polishing efficiency is remarkably improved, and the polishing quality is improved. And finally, the high-flatness copper plate is obtained.

The invention discloses a method for regulating and controlling heterogeneous growth of a layered double-metal hydroxide film in a friction stir welding seam area, and relates to the technical field of friction stir welding corrosion protection. The method comprises the following steps: performing friction stir welding on two magnesium alloy plates to obtain a weld zone; and placing the weld zone in an LDHs growth solution for hydrothermal reaction. The reaction time is regulated and controlled through a hydrothermal method, and an MgAl-LDHs film layer grows in a weld zone. More electrochemical active sites are formed in a welding seam area due to severe plastic deformation in the welding process, more precursors are promoted to be formed in the initial growth stage, and the LDHs structure is induced to grow more compactly and more uniformly due to inherent defects of the welding seam area, so that structural optimization of an LDHs film layer is realized, and the welding seam area is better protected from being corroded.

The application belongs to the technical field of cord steel preparation, and particularly relates to a high-strength and high-plasticity cord steel and a preparation method thereof, the preparation method comprising the following steps: S1, obtaining a cord steel casting blank, heating, rolling and cooling the cord steel casting blank to obtain a cord steel wire rod, and the structure of the cord steel wire rod is a pearlite structure with an average interlamellar spacing of 95-100 nm; S2, cold drawing the cord steel wire rod to obtain a cord steel wire material, and the total surface reduction of the cold drawing is greater than or equal to 85%; and S3, heat treating the cord steel wire material to obtain the high-strength and high-plasticity cord steel, and the holding temperature of the heat treatment is 280-300 DEG C. According to the application, a pearlite matrix is obtained through alloy composition and cooling design, and severe plastic deformation is performed to construct an initial state with high defect density, low-temperature heat treatment is adopted to drive short-range diffusion of interface carbon atoms to construct a composition gradient and drive diffusion of micro-alloy elements to regulate nanometer precipitates, and the interface plasticization and precipitation reinforcement are synergized.

The invention discloses a preparation method of a high-strength aluminum-magnesium-manganese alloy material, and belongs to the technical field of metal materials. The method comprises the following steps: taking aluminum as a matrix, and adding elements such as magnesium, manganese, zinc, copper, zirconium and titanium to prepare a master melt; the preparation method comprises the following steps: preparing yttrium oxide and other nano ceramic suspension liquid, atomizing and drying into powder, and blowing into a melt to introduce nano particles; and through severe plastic deformation such as semi-continuous casting, homogenization heat treatment, equal channel angle channel extrusion and the like, hot rolling and aging treatment, dispersion strengthening of the nano-particles is achieved. Optimization includes nano-particle replacement, multiphase strengthening, parameter adjustment, in-situ phase formation and the like, alloy grains are refined to 80-200 nm, and the strength is remarkably improved. Compared with the prior art, the process is environmentally friendly, accurate in control and suitable for high-strength application of an inverter shell and the like, the tensile strength can reach 450 MPa or above, and the ductility is larger than or equal to 10%.

The invention relates to a high-performance bismuth telluride-based thermoelectric material and a preparation method thereof. According to the method, a preformed blank is subjected to a multi-stage thermal deformation process, specifically, first-stage thermal extrusion is conducted at the temperature of 430-530 DEG C and the medium extrusion ratio, and densification and texturing are preliminarily completed; then, second-stage hot extrusion is immediately carried out at the temperature of 350-450 DEG C under the high extrusion ratio, and high-density dislocation is introduced through violent plastic deformation; and in the third stage, equal-channel angular pressing can be adopted for subsequent shear deformation, so that the dislocation density is further increased, and grains are refined. By accurately controlling the time sequence and strength of a thermal field and a shear force field, a multi-mode defect structure from a nano precipitated phase and a crystal boundary in-place error network is cooperatively constructed in the material, and full-spectrum scattering of phonons is realized, so that the crystal lattice thermal conductivity is remarkably reduced while good electric transport performance is kept.

The invention discloses an ultra-fine grain high-plasticity copper-silver alloy stranded wire and a preparation method thereof, and belongs to the technical field of copper alloy materials, the copper-silver alloy stranded wire is composed of, by mass, 2%-4% of silver, 0.05%-0.1% of zirconium and the balance copper, the average grain size ranges from 200 nm to 500 nm, the tensile strength is larger than or equal to 500 MPa, the ductility is larger than or equal to 8%, and the electric conductivity is larger than or equal to 85% IACS. The preparation method comprises the steps of vacuum induction melting, homogenizing annealing, hot extrusion cogging, equal-channel angular pressing, cold drawing, stranding forming and low-temperature recovery annealing, the ultra-fine grain structure is regulated and controlled through the zirconium microalloying and composite severe plastic deformation process, and the bending life is prolonged by more than three times compared with that of a common copper stranded wire; the cable bending device can be used for frequent bending scenes such as robot cables and medical equipment cables.

The invention discloses a preparation method of a high-strength and high-conductivity graphene metal-based composite material, and belongs to the technical field of metal-based composite materials. The invention relates to a preparation method of a high-strength and high-conductivity graphene metal-based composite material, which comprises the following steps: compounding spherical graphite serving as a raw material with metal powder, molding and sintering the mixed powder to obtain an ingot blank, and finally gradually stripping a graphite sheet layer through severe plastic deformation to form graphene, thereby obtaining the graphene metal-based composite material. After the spherical graphite and the metal powder are mechanically mixed and ball-milled for a certain time, all phases of the powder are uniformly distributed, and after an ingot blank is prepared and sintered, multi-stage severe plastic deformation is carried out. In the process of large plastic deformation, graphite flake layers are gradually peeled off and arranged in a certain direction, and the graphene metal matrix composite material is finally obtained after multi-stage plastic deformation.

The application discloses a heat treatment process for a metal alloy after large plastic deformation and relates to the technical field of metallurgy. The process is de-energization treatment before solid solution treatment. The de-energization treatment is heat preservation for 12 hours or more under the condition that the solid solution temperature of the metal alloy is 1 / 3 or less. The application realizes the transformation of the structure from a metastable state to a stable state based on the dissipation of the energy of the alloy structure after deformation, and then realizes the regulation and optimization of the second phase while inhibiting the grain growth.

The invention relates to a preparation method and application of a titanium hydrogen storage alloy block. After the titanium hydrogen storage alloy block prepared by the preparation method disclosed by the invention is stripped from the outer-layer titanium shell, the titanium hydrogen storage alloy block can be directly subjected to hydrogen absorption and desorption reaction at normal temperature in a complete block form without secondary treatment; the problem that the titanium hydrogen storage alloy block is difficult to strip due to too compact shell is effectively avoided; the titanium waste is adopted as the raw material, and low raw material cost is maintained. In addition, according to the preparation process, the traditional procedures such as smelting crushing or severe plastic deformation are simplified, the titanium hydrogen storage alloy block capable of being directly used is obtained only through one-step sintering, addition of high-cost rare earth elements is avoided, and the advantages of short procedures and low cost are both considered.

The invention relates to the field of metallurgy, in particular to a production method of a low-cost high-quality high-carbon bearing steel GCr15 wire rod, the process route comprises the steps of steelmaking, continuous casting, heating in a heating furnace and rolling, crystallizer electromagnetic stirring and tail end electromagnetic stirring are used for continuous casting, and a continuous casting billet dynamic soft reduction process is used. The compression ratio of the cross section area of a casting blank to a final wire rod is larger than or equal to 160, and a high-temperature decarburization prevention coating is sprayed before the casting blank enters a furnace. Through the high compression ratio and severe plastic deformation, coarse carbides are crushed into fine dispersed particles, original as-cast dendritic crystals are crushed, and macrosegregation is relieved; through continuous casting crystallizer electromagnetic stirring, tail end electromagnetic stirring and large continuous casting blank rolling reduction, casting blank element segregation is improved, and the core compactness is improved; through casting blank shot blasting and anti-decarburization coating spraying, the high-temperature diffusion and anti-decarburization requirements of the heating furnace are balanced; and by controlling the rolling temperature and the cooling rate, precipitation of network carbides is inhibited, and the control level of the bearing steel wire rod carbides is further improved.

The invention discloses a friction stir deposition method and a friction rolling deposition forming device. The friction stir deposition method comprises the step of rolling a deposition layer formed by friction stir deposition. The friction rolling deposition forming device comprises friction stir deposition equipment and rolling equipment, the rolling equipment comprises a rolling wheel, and after a deposition layer is formed through friction stir deposition, the rolling wheel can roll the deposition layer. Through rolling, the deposition layer generates severe plastic deformation and induces dynamic recrystallization, the grain refining effect is achieved, meanwhile, replastic flowing at the interface of the deposition layer and the substrate is promoted, and the interface bonding strength of the deposition layer and the substrate is remarkably improved; the friction contact between the tool head and the deposited workpiece can be weakened, the tool head is prevented from being abraded, and the service life of the tool is prolonged.

The invention belongs to the technical field of material surface mechanical strengthening, and particularly relates to a construction method of a variable-diameter thin-wall shaft surface gradient nanostructure, which is suitable for surface strengthening machining of key parts of high-end equipment such as a gas turbine transmission shaft and a wind power main shaft. A gradient nanostructure layer with a certain depth is formed on the surface of the variable-diameter thin-wall shaft part through the surface nanocrystallization technology, and the surface of the variable-diameter thin-wall shaft part is remarkably strengthened. The core of the method is that a tool platform for conducting surface nanometer strengthening on the large-size and complex-shape shaft piece is built; and meanwhile, in the surface severe plastic deformation treatment process, rigidity compensation is provided for supporting the thin-wall structure, and the thin-wall shaft piece is prevented from deforming and losing efficacy. And finally, the gradient nanostructure layer with the obvious strengthening characteristic is completely obtained on the surface of the thin-wall shaft piece. According to the method, the problem of keeping the structural stability of the variable-diameter thin-wall shaft part in the surface machining process can be solved, and meanwhile a machining platform and a solving mode are provided for surface nanocrystallization treatment of large-size complex devices.

The application discloses a preparation method of large bulk ultra-fine grain magnesium alloy by severe plastic deformation, and comprises the following steps: S1, assembling a mold; S2, placing a convex die into a feeding channel through linear motion of an axial feeding unit; S3, the axial feeding unit goes down, and a torsion unit is started at the same time; due to the block of an extrusion cone angle area, a cylindrical blank is extruded in the extrusion cone angle area, gradually transversely filled and upset, and the extrusion cone angle area is filled; S4, the blank flows from the extrusion cone angle area to a secondary back pressure area; and S5, composite upsetting deformation: the blank enters an extrusion forming area, in the extrusion forming area, the blank is subjected to the continuous action of axial pressure on one hand and the constraint of the inner wall of an inner convex rib insert on the other hand, and under the combined action, the blank is subjected to composite upsetting deformation, the grains are fully refined and uniformly distributed, and finally, large bulk magnesium alloy with an ultra-fine grain structure is formed. The application optimizes stress distribution, realizes uniform grain refinement and efficient forming of the magnesium alloy in the process of rotary forward extrusion.

The application relates to the field of bearing machining, and particularly discloses a machining process for a bearing outer ring, which comprises the following steps: S1. pretreatment; S2. surface nanocrystallization treatment; S3. rough grinding; S4. fine grinding; S5. superfinishing; and S6. cleaning. The surface nanocrystallization treatment is added before grinding, the raceway surface layer is subjected to severe plastic deformation through high-speed projectile impact, a gradient nanocrystalline structure layer which is gradually changed from the surface nanocrystalline to the coarse grain in the center is formed, the structure layer can improve the surface hardness and strength, reduce the subsequent grinding force and grinding heat, inhibit thermal damage and organizational phase change, deep stable residual compressive stress is introduced into the surface layer, the tensile stress generated during grinding is offset, the raceway is finally in a beneficial compressive stress state, and therefore, a high-hardness and low-damage high-quality surface layer is obtained, and the bearing matching precision, running stability and service reliability are improved.

The invention provides a preparation method of an ultra-fine grain ODS-Cu composite material for synergistically improving mechanical-electrical conductivity, and relates to the technical field of copper-based composite materials and preparation. The method comprises the following steps: preparing superfine ODS-Cu powder containing 0.5-1.5 wt% of Al2O3 by adopting an in-situ endogenous oxidation-reduction method, carrying out cold isostatic pressing, sintering under a hydrogen protection atmosphere, carrying out hot extrusion and annealing to obtain a densified ODS-Cu formed blank, and drawing or rolling to obtain an intermediate plate; carrying out low-temperature annealing on the intermediate plate and then transferring the intermediate plate into liquid nitrogen until the core temperature of the plate is less than or equal to-150 DEG C; and the obtained plate is subjected to multi-pass cold rolling treatment, and the composite material is obtained. Compared with similar copper-based dispersion strengthening or severe plastic deformation routes in the prior art, the tensile strength and the yield strength can be improved by more than 10%, the ductility can be improved by more than 50%, the electric conductivity is higher than 75% IACS, and the softening temperature is higher than 900 DEG C.

The application discloses a kind of in-situ generation of rich alumina protective layer on the surface of rare earth magnesium alloy fast transient ultrasonic processing method and its application, belong to metal material surface engineering and modification technical field.Method includes: providing magnesium alloy workpiece containing aluminum and rare earth element, using ultrasonic tool head to workpiece surface in oxygen-containing environment Mechanical contact and high-frequency vibration irradiation;Through ultrasonic friction heat and the coupling effect of severe plastic deformation, induce surface layer aluminum element rapid diffusion and oxidation, in 5-15 seconds in-situ growth with alumina as main dense protective layer.The protective layer presents black, with amorphous-nanocrystalline composite structure of size increasing from surface to heart.This application does not need electrolyte and external heat source, process green environmental protection and extremely efficient, the obtained oxide layer and matrix form firm metallurgical bonding, significantly improve the surface hardness, wear resistance and corrosion resistance of magnesium alloy, suitable for industrialization online processing.

The invention relates to a casting and forging functional structure for improving the strength of a cabin casting, which is characterized in that by driving an insert to transversely withdraw, a withdrawing gap is formed between adjacent lower modules, and the lower modules are pushed to transversely move to extrude semi-solid aluminum; and after the retreating gap disappears, the insert is reset to form transverse blocking on the lower die piece, so that the semi-solid aluminum is subjected to high-pressure forging and pressing which are controllable in the longitudinal and transverse sequence in sequence in the solidification process. The multidirectional alternate severe plastic deformation forces internal grains to be fully crushed, rheologically and dynamically recrystallized in all directions, and the problems of uneven grain refinement and unbalanced stress distribution caused by traditional single-direction extrusion are effectively solved. And meanwhile, the retreating / resetting design of the lower die piece and the insert ensures that the transverse extrusion force is uniformly transmitted to the whole side wall of the casting, clamping stagnation or insufficient local extrusion caused by rigid collision of the die is avoided, and therefore the internal quality and the overall strength of the casting are improved.

The application discloses a segmented superplastic deformation method of large-grain magnesium alloy and belongs to the technical field of magnesium alloy plastic forming. The application directly takes a large-grain magnesium alloy blank which is not subjected to severe plastic deformation pretreatment as an object, and realizes forming by regulating a deformation rate in stages after heating. Firstly, deformation is carried out at a high strain rate, dynamic recrystallization is induced to refine the coarse-grain structure in situ, when the microstructure evolution or mechanical response reaches a predetermined state, the strain rate is switched to a low strain rate, and the grain boundary sliding mechanism is activated to complete superplastic flow. The method effectively solves the problems of complex pretreatment process and low efficiency in the traditional process, and is suitable for low-cost preparation of complex components in the fields of aviation, aerospace and transportation.

The invention provides a titanium target for sputtering, a method for producing the same, and a method for producing a titanium-containing thin film. Specifically disclosed is a titanium target for sputtering, which has a recrystallized structure having an average crystal grain size of 1 [mu] m or less. In addition, the present invention also provides a method for manufacturing a titanium target for sputtering, the method comprising: a step for obtaining a processed plate by performing large strain processing on a cut titanium ingot; a step for obtaining a rolled sheet by cold-rolling the processed sheet at a rolling rate of 30% or more; and a step for heat-treating the rolled sheet at a temperature of 320 DEG C or less.

The application belongs to the technical field of surface modification of metal materials, and particularly relates to a method for preparing an aluminum coating on a titanium alloy surface by using a friction stir deposition technology, which comprises the following steps: taking a titanium alloy as a substrate, using pure aluminum or an aluminum alloy as a friction deposition rod, and rotating and rubbing the friction deposition rod along the surface of the substrate under the action of an axial pressure so that the friction deposition rod is softened and deposited on the substrate under the action of friction heat and severe plastic deformation, so as to generate an aluminum coating on the titanium alloy surface. In the application, the friction deposition rod is softened and deposited on the substrate to be protected under the action of severe plastic deformation which is jointly generated by friction heat and an axial force between the deposition rod and the titanium alloy substrate to be protected, the prepared coating is well combined with the substrate, the microstructure of the coating is refined, and the high-temperature oxidation resistance of the coating is excellent.

The invention discloses a TWIP effect metastable state austenitic steel welding method, a welding device is provided with a material conveying cavity, the material conveying cavity is sequentially connected with a first-stage material conveying cavity and a second-stage material conveying cavity from top to bottom, and a spiral material conveying assembly extends into the first-stage material conveying cavity from the top; the lower end of the second-stage material conveying cavity is connected with a stirring head; a channel communicated with the second-stage material conveying cavity is embedded in the stirring head; a heating assembly is installed outside the second-stage material conveying cavity. According to the method, austenite stable elements or reinforced particles are mixed into a welding seam, the austenite stable elements are accelerated to be quickly diffused into austenite by utilizing the thermal diffusion effect and the pipe dislocation diffusion effect, and a welding joint containing the austenite is obtained through quenching partition heat treatment; in addition, the severe plastic deformation can obviously refine grains, and the austenite grain size refinement can also improve the austenite stability; meanwhile, a welding area is fully heated, so that a large number of annealing twin crystals are formed in a welding seam; based on the method, high-quality welding of the metastable-state high-strength steel is achieved.

The present application relates to a kind of methods for recycling metal by EB smelting rapid continuous casting extrusion severe deformation, after washing and classification of recycled metal regenerative material, respectively, proportioning and mixing, adding electron beam cold bed furnace and smelting, the molten metal obtained is transferred into subsequent continuous casting extrusion severe plastic deformation device by electromagnetic pump heat preservation, the degree of severe plastic deformation is greater than 2, and special organization and defects in regenerative material are effectively eliminated, after short process rapid deformation, after subsequent heat treatment and surface treatment, regenerative metal is obtained, and then the scrap and machining allowance generated are recycled into the material recycling process again.The present application can recycle metal materials, significantly reduce the total process use cost of high value materials, comprehensively improve the service performance of metal materials, and save a lot of resources.

The present invention relates to a previously unreported nanoscale crystal mass that comprises a noble metal. This noble metal nanoscale crystal mass comprises a polycrystalline body of a noble metal that has a purity of at least 99%, the median diameter of the crystal grains that constitute the polycrystalline body being no more than 0.1 μm. It is difficult to micronize the crystal grains of noble metals by cold severe plastic deformation and heating. Thus, this noble metal nanoscale crystal mass is produced by powder sintering that uses a fine noble metal powder as a starting material. The production method includes a sintering step for sintering a green compact of the noble metal powder at a sintering temperature of no higher than 0.4×Tm (°C) (Tm being the melting point (°C) of the noble metal). At the sintering step, after the green compact has been raised to the sintering temperature, it is necessary to rapidly lower the temperature without raising or holding the temperature.