591 results about "Ductility" patented technology

The invention discloses a composite protective structure resistant to blast shock which is mainly a point truss honeycomb integral protective structure formed by a honeycomb tensile layer and a lattice truss-type compression resistance layer through welding spots and connecting keys, and a foam energy absorbing layer is added on the outer layer. According to the composite protective structure, theforce transmission path of a concrete protective structure under the action of blast is innovatively optimized, the resistance level of the protective structure can be greatly improved, and the structure ductility is improved; and the dispersion of concrete fragments in the structure can be restrained, and the phenomenon of blast and explosion-induced collapse of similar traditional concrete protective structures is eliminated.

The invention belongs to the technical field of metal material engineering, and relates to a light high-toughness low-cost aluminum alloy and a preparation method thereof.The alloy comprises, by mass, 7.0%-9.2% of Mg, 2.5%-4.0% of Zn, 0.06%-0.20% of Zr, 0.01%-0.03% of Sb, main impurities including Fe smaller than or equal to 0.15%, Si smaller than or equal to 0.12%, other single impurities smaller than or equal to 0.05%, the total impurity smaller than or equal to 0.15% and the balance Al. Compared with 2xxx series and 7xxx series aluminum alloys, the alloy has certain advantages in the aspects of density, specific strength, ductility, corrosion resistance and the like, and has a remarkable cost advantage compared with a low-density aluminum-lithium alloy, so that the core competitiveness of an alloy product is improved, and the alloy product has the potential of becoming a next-generation commercial aluminum alloy.

Provided is a steel sheet that may be used for automobile parts and the like, and to a steel sheet having an excellent balance of strength and ductility, an excellent balance of strength and hole expansion ratio, and an excellent yield ratio evaluation index, and a method for manufacturing the same. The steel sheet includes: by wt %, C: 0.1 to 0.25%, Si: 0.01 to 1.5%, Mn: 1.0 to 4.0%, Al: 0.01 to 1.5%, P: 0.15% or less, S: 0.03% or less, N: 0.03% or less, B: 0.0005 to 0.005%, a balance of Fe, and unavoidable impurities; and as microstructures, bainite, tempered martensite, fresh martensite, retained austenite and unavoidable structures.

The invention discloses an Al-Mg-Zn aluminum alloy plate with excellent strong plasticity and light weight characteristics as well as a preparation method and application of the Al-Mg-Zn aluminum alloy plate. The alloy comprises the following components in percentage by mass: 5.0%-5.5% of Mg, 1.5%-2.0% of Zn, 0.4%-0.5% of Mn, 0.1%-0.3% of Cu, 0.15%-0.25% of Sc, 0.1%-0.15% of Zr, 0.05%-0.15% of Ag, less than or equal to 0.1% of impurities and the balance of Al. The density is not more than 2.63 g / cm < 3 >, the tensile strength is not less than 470 MPa, and the ductility is not less than 23%. The preparation method comprises the steps of high-purity raw material smelting and casting, two-stage homogenization, hot rolling, intermediate annealing, cold rolling, solid solution treatment and single-stage aging. Wherein the total pressing amount of hot rolling is 80-85%, the total pressing amount of cold rolling is 20-35%, and the single-stage aging time is 120-140 DEG C * 16-24 h. The microstructure of the alloy is characterized in that the average size of dispersed AlSc particles is smaller than or equal to 100 nm, the area fraction of deformed grains is larger than or equal to 70%, the average size of nanometer beta-AlMg and T-Mg (Al, Zn) composite precipitated phases is smaller than or equal to 20 nm, the number density is larger than or equal to 1 * 10 < m >, the area fraction of micron-order second phases is smaller than or equal to 0.5%, and the alloy is only formed by impurity Fe. According to the method, the traditional two-stage aging process is simplified, low density, high strength and high plasticity are synchronously improved, and the method is suitable for large-scale industrial application.

This invention provides a high-strength, high-ductility austenitic stainless steel and its production method. The composition is: C 0.045%-0.085%, N 0.10%-0.40%, Si 0.90%-1.55%, Cr 16%-20.1%, Ni 7.5%-12.5%, Mn 1.5%-3.5%, Mo 1.5%-3.0%, Nb 0.08%-0.22%, Ti 0.015-0.065%, O≤0.005%, P≤0.003%, S≤0.003%, with the remainder being Fe and unavoidable impurities. Compared with existing technologies, this invention obtains a reasonable grain size and second-phase particles through nitrogen, titanium, and niobium alloying, combined with low-temperature rolling and appropriate annealing and aging heat treatment, thus developing an austenitic stainless steel with excellent mechanical properties. It achieves excellent ductility at a high strength level, with a strength-ductility product as high as 60 GPa·s.

The invention belongs to the technical field of metal materials, and relates to a CoNiVAlX (x is greater than or equal to 0 and less than or equal to 0.5) multi-principal-element heterostructure entropy alloy system and a preparation method thereof. The chemical composition (atomic percent) of the alloy contains Co, Ni, V, Al and a trace regulator, flexible matching of strength and toughness is realized in a wide temperature range of-263 DEG C to 800 DEG C by regulating the Al content and a thermal mechanical treatment process, and various mechanical states such as'high ductility-medium strength 'and'high strength-medium ductility' can be obtained; the preparation process is based on a mature metallurgical technology and does not depend on special equipment, and large-size stable preparation can be achieved. Tests prove that the alloy system is wide in toughness and adjustable, the toughness balance in a wide temperature range is realized, the application requirements in an extreme environment are met, and the alloy system has a good industrial popularization prospect.

A process for forming extruded products using a device having a scroll face configured to apply a rotational shearing force and an axial extrusion force to the same preselected location on material wherein a combination of the rotational shearing force and the axial extrusion force upon the same location cause a portion of the material to plasticize, flow and recombine in desired configurations. This process provides for a significant number of advantages and industrial applications, including but not limited to extruding tubes used for vehicle components with 50 to 100 percent greater ductility and energy absorption over conventional extrusion technologies, while dramatically reducing manufacturing costs.

The invention discloses a method and system for determining the optimal stress orientation of a concrete special-shaped sheet column, and relates to the technical field of constructional engineering. According to the method, a correlation model of special-shaped contour parameters and load conditions is constructed, a mechanical property key direction set is extracted, the screening range is narrowed, the optimal orientation determination efficiency is greatly improved, the design period is shortened, and the optimal orientation determination efficiency is improved based on multi-dimensional screening of all-circumferential inertia moment distribution, a rigidity curve and a bending moment contribution ratio. Core indexes such as section ultimate bearing capacity and ductility are comprehensively evaluated by combining stress simulation of a concrete nonlinear constitutive relation; through overall structure collaborative checking calculation and node stress analysis, it is ensured that the orientation meets the mechanical requirements of components and adapts to lateral force resistance and stress continuity of the overall structure, in combination with building construction requirements and node compressive strength redundancy optimization, the scheme of optimal mechanics but construction conflicts is eliminated, safety redundancy is reserved, the structure anti-disaster stability is guaranteed, and the construction safety is improved. And meanwhile, the method adapts to complex working conditions and specification requirements and ensures that the scheme can be directly applied.

The invention discloses a multi-cavity aluminum alloy battery pack shell extrusion-bending process optimization method, and relates to the technical field of aluminum alloy machining. According to the method, 6000 series aluminum alloy serves as a base material, and the problems of cracking, resilience, section deformation and uneven performance of a profile in the traditional process are solved through the six-step core process of compound trace element regulation and control, gradient heating ingot casting, PID temperature control extrusion, segmented quenching temperature control, multi-roller cooperative bending and online structure monitoring. The strength and plasticity of the alloy are improved through Mn / Zr or Cu / Ag composite microalloying, extrusion-bending continuous forming and real-time grain boundary migration and dislocation density monitoring are combined, and the multi-cavity structure size precision (the broad side error is + / -1.87 mm, and the narrow side error is + / -0.40 mm) and the mechanical property (the tensile strength is larger than or equal to 200 MPa, and the percentage elongation after fracture is larger than or equal to 8%) both reach the standard. The process shortens the processing period by more than 30%, improves the material utilization rate to 92%, is suitable for large-scale mass production of new energy automobile battery pack shells, and provides key technical support for automobile lightweight.

The invention relates to the technical field of high-speed cable shielding materials, and discloses a manufacturing method of rolled copper foil for high-speed cable shielding. The method comprises the following steps: preparing a copper plate; performing multi-pass cold rolling on the copper plate to form an elongated grain structure oriented along the rolling direction; performing controlled annealing on the cold-rolled copper foil to recover plasticity and inhibit complete recrystallization; the target thickness is obtained through finish rolling; carrying out finishing rolling on at least one surface of the copper foil by adopting a mirror surface working roller so as to reduce the surface roughness; and performing surface smoothing or passivating treatment to inhibit oxidation and performance degradation. Therefore, the obtained rolled copper foil has good ductility, structural stability and high-frequency performance.

The invention discloses an interface enhanced composite shear wall based on a high-ductility cement-based material. The high-ductility cement-based composite materials are formed in edge constraint areas on the two sides of the shear wall, and the common concrete is formed in a core area in the middle of the shear wall. The interface separation net is a high-strength ribbed non-dismantling formwork net and is vertically arranged at the junction of the edge constraint area and the core area, the section of the interface separation net is in a periodic concave-convex wave shape or a stepped shape, and a macroscopic mechanical meshing interface is formed. The interface seaming ribs are U-shaped ribs and are horizontally arranged at the positions of the inter-rib slurry penetrating nets of the interface separation net in a penetrating mode, one ends of the interface seaming ribs are anchored to the edge constraint area common steel bars, and the other ends of the interface seaming ribs extend into the core area and are connected with longitudinal and transverse rib cross joints of the composite material grid ribs in a hooked mode; the problems of rigidity mutation and slippage of the heterogeneous material interface are solved by utilizing the geometric occlusion effect of the interface separation net and the anchoring effect of the deep bolt pins and joints of the interface sewing ribs, cooperative work of a high-ductility material and common concrete is achieved, and good anti-seismic performance is achieved.

The invention discloses a method for preparing a high-toughness titanium alloy pipe through precision forging and the pipe prepared through the method. The pipe prepared through the method is small in anisotropy, the strength in all directions reaches 1100 MPa or above, the ductility reaches 10% or above, the impact toughness reaches 25 J / cm < 2 > or above, and the structure and performance uniformity is good.

This invention relates to the field of metallic materials technology, and more particularly to a negative enthalpy duplex stainless steel material and its preparation method, which possesses high strength, high plasticity, and high corrosion resistance. The negative enthalpy duplex stainless steel material is Fe... a Cr b Ni c Mo d Mn e C f Si g Ti h Al i V j Wherein, a, b, c, d, e, f, g, h, i, and j correspond to the mass percentages of each element: a = 60-70 wt%, b = 15-20 wt%, c = 10-15 wt%, d = 0-5 wt%, e = 1-5 wt%, f = 0.015 wt%, g = 0-1 wt%, h = 0-3 wt%, i = 0-0.5 wt%, j = 0-0.5 wt%, and d, g, h, i, and j are not zero. This series of negative enthalpy duplex stainless steel materials all contain ferrite and austenite in their structure, and the microstructure and mechanical properties of the alloy can be controlled by adjusting the proportions of different metal elements. This series of negative enthalpy duplex stainless steel materials exhibits high strength and high ductility. Simultaneously, negative enthalpy duplex stainless steel materials exhibit excellent corrosion resistance.

The invention provides a high-strength and high-ductility damage self-repairing cement-based composite material based on spiral memory alloy fibers and a preparation method of the high-strength and high-ductility damage self-repairing cement-based composite material, and belongs to the technical field of underwater engineering concrete structures. According to the invention, the matrix mix proportion of the cement-based composite material and the hybrid reinforcement effect of the three fibers on the matrix are redesigned, so that the tensile strain capacity is also remarkably improved while the strength of the UHPSC is improved, and the deformation ductility and the cumulative energy dissipation capacity of the cement-based composite material are further remarkably enhanced; as the spiral superelastic SMA fibers have self-resetting capacity, restoring force can be provided for the unloaded cement-based composite material, tensile cracks of the cement-based composite material are promoted to be automatically closed or the width of residual cracks of the cement-based composite material is obviously reduced, and on the basis, the self-healing capacity of an incompletely hydrated cementing material in the cement-based composite material is matched, so that the self-healing performance of the cement-based composite material is improved. And the UHPSC material can present a good damage self-repairing effect.

The invention discloses high-strength heat-resistant aluminum-copper alloy powder, a 3D printing application method and an aluminum product. Relates to the technical field of metal material and additive manufacturing, in particular to a high-strength heat-resistant aluminum alloy material suitable for selective laser melting. The alloy powder is composed of Cu, Sc, Ni, Ce, Si, Mn, Ti, Fe and Al, the content of Cu ranges from 5 wt% to 15 wt%, the content of Sc ranges from 0.3 wt% to 2 wt%, the content of Ni ranges from 0.5 wt% to 5.5 wt%, the content of Ce ranges from 0.5 wt% to 5.5 wt%, and an Al7Cu4Ni eutectic phase is generated in situ in the printing process. And through a multi-element synergistic strengthening mechanism, the solidification interval is effectively reduced, cracks are inhibited, and meanwhile fine grain strengthening and precipitation strengthening are achieved. After SLM forming and low-temperature heat treatment, the obtained aluminum product has ultrahigh strength, good plasticity and excellent heat resistance, the tensile strength exceeds 650 MPa, the hardness exceeds 180 HV0.2, the ductility exceeds 7%, and the aluminum product meets the requirements for light high-strength heat-resistant components in the high-end fields such as aerospace and the like.

The invention provides a manufacturing method of a copper-nickel alloy pipe with excellent high-temperature plasticity. The manufacturing method comprises the following steps that S1, Ni, Fe, Mn, Ti, CuMg20 and Cu raw materials are weighed according to components of a nickel-based alloy pipe; s2, raw materials of Cu, Ni, Fe, Mn and Ti are smelted, CuMg20 is added for deoxidation, and an alloy round ingot is obtained through casting; s3, the alloy round ingot is subjected to homogenizing annealing; s4, forging and upsetting the alloy round ingot to obtain an upset round ingot; s5, performing hot extrusion on the upset round ingot to obtain a tubular billet; s6, the tubular billet is subjected to cold rolling, and annealing is conducted between pass cold rolling; and S7, the tubular billet is subjected to heat treatment, and the copper-nickel alloy pipe is obtained. According to the method, the uniformity and thermoplasticity of the alloy structure are improved, the plasticity and comprehensive mechanical performance of the copper-nickel alloy pipe in the high-temperature environment are remarkably improved, and the method is stable, high in repeatability and beneficial to large-scale production of the high-quality copper-nickel alloy pipe.

Provided are a solder alloy, a solder paste, a solder ball, and a solder joint which have a low melting point, are excellent in ductility, shear strength, and heat cycle resistance, further suppress the occurrence of open defects, and in addition, have reduced residual voids even at the time of joining in a large area. A solder alloy has an alloy composition of, by mass %, Bi: 35.0 to 68.0%, Sb: 0.1 to 2.0%, Ni: 0.010 to 0.050%, Ge: 0.007 to 0.090%, with the balance being Sn. Preferably, the alloy composition further contains, by mass %, at least one of Co, Ti, Al, Mn, As, Fe, Pd, Zn, Zr, Pb, In, Ce, P, and Ga: 0.1% or less in total. Further, this solder alloy can be suitably used for solder pastes, solder balls, and solder joints.

Provided are a high-strength hot-rolled steel sheet having high strength, high ductility, excellent strain dispersibility, high stretch flangeability, and bendability, a member, and methods for manufacturing the same.　The high-strength hot-rolled steel sheet has a prescribed component composition, and has a steel structure in which, in terms of area ratio, the total of bainite and tempered martensite is 80.0% or more, pearlite is 10.0% or less, retained austenite is 15.0% or less, the total of retained austenite and pearlite is 1.0% or more, the total of tempered martensite and bainite having a circle-equivalent diameter of 5.0 μm or more is 10.0% or less, and the proportion of line segments having a hard phase fraction of 20.0% or more among line segments having a length of 200 μm parallel to the rolling direction is 30.0% or less, the tensile strength TS (MPa) and the component composition (mass%) satisfy the expression 0 ≦ 730 + 2000 × (C + Si / 16 + Mn / 40 + Al / 18 + Cr / 40 + Ni / 40 + Mo / 20 + Ti / 3) – TS ≦ 250, where each element symbol in the formula represents the content (mass%) of each element, and the high-strength hot-rolled steel sheet has a tensile strength of 980 MPa or more.

The invention relates to high-strength and high-ductility wear-resistant medium manganese steel and a preparation method thereof, belongs to the technical field of ferrous metallurgy, and aims to solve at least one of the problems that in the prior art, medium manganese steel is low in initial yield strength and difficult to meet the application requirements of high-wear-resistant parts, high plasticity and high wear resistance are difficult to consider, and long-term stable service is difficult to realize in a high-wear environment. The invention relates to wear-resistant medium manganese steel with high product of strength and elongation. The medium manganese steel comprises the following chemical components in percentage by mass: 0.35%-0.45% of C, 0.75%-1.25% of Si, 8.5%-11.5% of Mn and the balance of Fe and inevitable impurities. By optimizing the alloy design of the medium-manganese wear-resistant steel, the limitation of insufficient initial hardness of the traditional medium-manganese steel is overcome, so that the medium-manganese steel can have higher surface hardness in a non-work-hardening stage, thereby showing excellent wear resistance in the initial service stage of a structural part; and the problem of high wear rate caused by insufficient hardness of the traditional high / medium manganese steel at the initial stage of wear is effectively avoided.

The invention relates to low cost high ductility cast aluminum alloys. Recycled (recycled) aluminum alloys are provided for casting into structural components, such as vehicle components. The aluminum alloys include at least 80 wt. % aluminum, 0.1 wt. % to 0.6 wt. % copper, 6.0 wt. % to 8.0 wt. % silicon, 0.10 wt. % to 0.60 wt. % magnesium, 0.10 wt. % to 0.50 wt. % zinc, 0.12 wt. % to 0.30 wt. % iron, 0.2 wt. % to 0.6 wt. % manganese, not greater than 0.15 wt. % titanium, 0.015 wt. % to 0.03 wt. % strontium, other elements in amounts not greater than 0.05 wt. % each and not greater than 0.15 wt. % total.

The invention discloses a welding process of a high-strength onboard load training device, which adopts a structural combination of a plurality of layers of steel plates and a high-ductility alloy connecting piece, and utilizes a composite welding device consisting of a welding head, a gas generating ring, a tempering heating ring and a slow cooling gas curtain ring which are coaxially arranged. The synergistic effect of an electric arc heat source and a laser heat source can be achieved in the welding process, a deep penetration weld joint is formed, and sufficient metallurgical bonding of the multi-layer steel plate and an alloy connecting piece is ensured. And in cooperation with annular protective gas, local tempering and slow cooling control, the welding seam structure can be effectively improved, the residual stress can be reduced, cold cracks and fatigue cracks are prevented, and therefore the strength and stability of a welding joint are remarkably improved.

According to the compression-resistant precision steel pipe, two positioning rings are symmetrically arranged in a steel pipe body, two butt-joint rings are symmetrically arranged at the two ends of the steel pipe body, butt-joint plates are arranged at the outer ends of the butt-joint rings, and the butt-joint rings can be inserted into the steel pipe body and make contact with the positioning rings; a plurality of grooves and reinforcing ribs are arranged on the outer wall of the steel pipe body, the reinforcing ribs are located in the grooves, a plurality of limiting holes are formed in the peripheral side of the butt joint plate, the two ends of each reinforcing rib can be inserted into the corresponding limiting hole, the steel pipe body is composed of an inner reinforcing layer and an outer toughness layer, the reinforcing layer made of alloy steel provides high-strength support, and the reinforcing ribs are made of steel. External pressure can be effectively resisted, and steel pipe deformation is prevented; the ductile layer made of low-carbon steel endows the steel pipe with good toughness, pressure impact can be buffered, brittle fracture is avoided, and the compressive property of the steel pipe is essentially improved through combination of the ductile layer and the steel pipe.

Provided is an austenitic heat-resistant steel having excellent creep rupture strength and excellent creep rupture ductility. The austenitic heat-resistant steel has a chemical composition comprising, in terms of mass%, 0.01-0.40% C, up to 3.00% Si, up to 3.00% Mn, up to 0.100% P, up to 0.100% S, 20.0-35.0% Cr, 20.0-48.0% Ni, 0.1-5.0% Mo, 0.01-1.50% Ti, 0.01-0.50% V, up to 0.030% N, up to 0.100% Al, 0.0001-0.0200% B, etc., and has an average austenite crystal grain size of 0.0-5.0 in terms of ASTM No. In the austenitic heat-resistant steel, the Ti, V, and Mo contents and a Ti amount, a V amount, and a Mo amount that are determined from an electrolytic extraction residue satisfy expression (i) and expression (ii).　(i): TiER+VER+MoER≤1.000 (ii): 1.00≤(Ti+V+Mo)-(TiER+VER+MoER)

Provided is a steel sheet which can be used for automobile parts and the like, and relates to a steel sheet having an excellent balance of strength and ductility, an excellent balance of strength and hole expansibility and excellent bending workability, and a method for manufacturing same.

A method for producing a steel sheet, the method containing the following successive steps:providing a cold-rolled steel sheet, the chemical composition of the steel containing in weight %: 0.15%≤C≤0.23%, 2.0%≤Mn≤2.8%, 1.0%≤Si≤2.1%, 0.02%≤Al≤1.0%, with 1.7%≤Si+Al≤2.1%, 0≤Nb≤0.035%, 0≤Mo≤0.3%, 0≤Cr≤0.4%, the remainder being Fe and unavoidable impurities,annealing the steel sheet at an annealing temperature TA so as to obtain a structure comprising at least 65% of austenite and up to 35% of intercritical ferrite,quenching the sheet at a cooling rate of at least 20° C. / s from a temperature of at least 600° C. down to a quenching temperature QT comprised between Ms−170° C. and Ms−80° C.,heating the sheet up to a partitioning temperature PT between 350° C. and 450° C. and maintaining the sheet at this temperature for a partitioning time Pt comprised between 80 s and 440 s,immediately cooling the sheet down to the room temperature,the steel sheet having a final microstructure consisting of, in surface fraction:between 40% and 70% of tempered martensite,between 7% and 15% of retained austenite,between 15% and 35% of ferrite,at most 5% of fresh martensite,at most 15% of bainite.

The invention discloses an automatic processing system and method for foamed plastic products with poor ductility, the automatic processing system comprises a machine body (1), a feeding frame (2), a cutting device (3), an oven (4), a discharging device (5), a shaping device (6), a conveying belt (8), a power device (9) and a control device (10), the cutting device is arranged between the feeding frame (2) and the oven (4) and used for cutting coiled materials into sheets with proper sizes, and the shaping device (6) is arranged on the conveying belt (8). The conveying belt (8) sequentially penetrates through the feeding frame (2), the cutting device (3), the oven (4) and the discharging device (5), and the shaping device (6) is arranged on the periphery of the discharging device (5). By the adoption of the system, the five working procedures of feeding, cutting, heating, modeling and blanking are controlled by the control device and completed in a unified mode, the consistency of products is greatly improved, the yield of the products is greatly improved, and the labor cost is greatly saved.

The application discloses a flexible metal composite skin structure capable of regulating local out-of-plane deformation and belongs to the technical field of metal skin structures. The application introduces a paper-cut structure on the surface of a metal skin, regulates mechanical response by changing characteristic parameters such as a paper-cut pattern and a metal skin thickness, so that the structure has high ductility and small plastic deformation characteristics, and the structure can recover to original deformation after the expansion of a protrusion of a driving device, thereby ensuring the continuity of a wing aerodynamic shape. The application meets the basic requirements of application to a flexible skin of a deformation wing, provides a feasible selection for the fusion of a gasbag anti-icing mechanism and a deformation wing, and is expected to be widely applied in the fields of aircraft deicing, spacecraft deicing and deformation wings.

The invention discloses a processing method of an anti-fracture piston skirt copper ring, which aims at solving the problems that MB7 alloy used by a marine diesel engine piston skirt copper ring is easy to generate lead emission, segregation and assembly fracture, adopts a composite casting mold of a copper ring molten steel jacket and a resin sand mold core, and is matched with bottom pouring type pouring to form a sequential solidification temperature gradient; a circulating water continuous chilling process is combined, so that the defect of non-uniform solidification of a low-melting-point phase is overcome, and meanwhile, copper matrix grains are refined to improve the ductility; step 1, casting mold preparation; 2, alloy smelting; thirdly, bottom pouring type sequential solidification pouring is conducted; 4, continuous chilling with circulating water; and 5, post-processing and assembling. According to the machining method for the anti-fracture piston skirt copper ring, the machined copper ring can bear 120 MPa circumferential pressure without cracks when being embedded into a piston skirt, the product percent of pass is increased, and the machining method is already applied to production of marine diesel engines in batches and is high in market share.

This invention discloses a high-elongation aluminum alloy for lightweight automotive components and its preparation method, relating to the field of aluminum alloy material technology. It features a hierarchical porous structure with surface micron-sized closed pores and a core nano-sized through-pore. The Ti and Mn elements synergistically form an Al-Ti-Mn martensitic phase transformation core region with Al, and the Cr element precisely controls the martensitic phase transformation initiation temperature to room temperature, ensuring stable triggering of the austenite-to-martensitic phase transformation and energy absorption during room-temperature collisions. This invention achieves initial impact buffering and gradual collapse energy absorption through a hierarchical porous structure with surface micron-sized closed pores and a core nano-sized through-pore. This dual energy absorption mechanism significantly improves the material's strength-ductility product, far exceeding that of traditional aluminum alloys.

The invention discloses an assembly type shear wall bolt connection box with a stress gradient transition function, and belongs to the technical field of assembly type reinforced concrete structure connection. The connecting box comprises a steel box body, an anchoring back plate arranged on the back face of the box body and array type anchoring ribs arranged on the anchoring back plate. The metal outer wall of the connecting box is coated with a buffer layer formed by a high-strength rubber elastomer or epoxy resin mortar, and the thickness of the buffer layer is gradually reduced in the anchoring direction, so that rigidity gradient transition from the steel box to the concrete is achieved. The structure can effectively weaken stress concentration near the end of the anchor bar, delays cracking and crushing of concrete on the edge of the connecting box, remarkably improves ductility and crack resistance of the vertical abutted seam joint of the fabricated shear wall, and better achieves the design goals of strong connection and weak components.