Surface nano-oxide dispersion strengthening method of high-strength high-toughness aluminum alloy powder and powder material thereof

Abstract

The application discloses a surface nano-oxide dispersion strengthening method of high-strength and high-toughness aluminum alloy powder and a powder material thereof, and relates to the technical field of powder metallurgy materials. The method takes aluminum-zinc-magnesium-copper-zirconium pre-alloy atomized powder as a matrix, disperses by means of polyvinylpyrrolidone and anhydrous alcohol, sequentially introduces magnesium-aluminum spinel nanoparticles, optional magnesium oxide nanoparticles and passivated magnesium nanoparticles dry coating, and embeds the nano-lattice into a surface layer through ceramic ball micro-blasting, removes organic matters in a vacuum in sections, and is activated at 405-435 DEG C, and then zinc powder is added for low-energy coating after cooling. The method is suitable for canning degassing, hot isostatic pressing and hot extrusion parts. The method can be scaled. In the obtained powder, the oxide is converted from prior powder boundary connected interlayer into intracrystalline non-connected dispersed particles, the boundary connectivity is reduced, the densification is improved, the fracture toughness, impact and high-cycle fatigue are significantly improved, and the powder fluidity is maintained and consistency is improved.

Description

Technical Field

[0001] This invention relates to the field of powder metallurgy materials technology, specifically to a method for surface nano-oxide dispersion strengthening of high-strength and high-toughness aluminum alloy powder and its powder materials. Background Technology

[0002] High-strength aluminum alloys have attracted widespread attention due to their high specific strength in aerospace load-bearing connectors, high-speed rotating components, and other lightweight structures sensitive to damage tolerance and high-cycle fatigue life. To balance near-net-shape forming and high-performance requirements, engineering often employs gas-atomized pre-alloyed powders, followed by vacuum degassing in cans, hot isostatic pressing densification, hot extrusion or hot forging, and then solution aging to prepare finished products. Simultaneously, to improve high-temperature strength and microstructural stability, there are also studies and patents on introducing nano-oxides onto the powder surface or utilizing the fragmentation of the inherent oxide film to achieve dispersion strengthening. However, aluminum and its alloy powders inevitably form nano-scale oxide films during powder preparation, storage, and transportation. These films are difficult to completely reduce or disappear during solid-state consolidation, and are stretched and folded by particle contact and plastic flow, accumulating at the original particle contact interface to form oxide strips or semi-continuous networks distributed along the prior powder boundary (PPB). When additional nano-oxides are applied to the surface or surface oxidation treatment is performed, factors such as poor interparticle wettability, nanoparticle agglomeration, and limited interfacial diffusion and migration may further promote the aggregation and connectivity of oxides at the PPB.

[0003] This type of oxygen-rich interface phase typically exhibits insufficient metallurgical bonding or discontinuous interface stiffness. Under the combined effects of residual stress from heat treatment and cyclic loading, it easily becomes a pathway for microcrack initiation and propagation, leading to reduced fracture toughness, impact absorption energy, and high-cycle fatigue strength, and increased performance dispersion. In actual manufacturing, to mitigate the influence of PPB (polybutadiene oxide) interconnected oxides, improvements are often made by increasing hot deformation, optimizing degassing and consolidation parameters, or introducing small amounts of active elements to promote film rupture. However, interconnected interface phases may still remain in high-strength alloy systems, varying with powder oxygen content, particle size distribution, and thermal history fluctuations, thus limiting the reliability and batch consistency of parts under complex loads. If left uncontrolled, this oxygen-rich network will reduce the allowable defect size and increase the uncertainty of non-destructive testing and life assessment.

[0004] The existing technical problems are:

[0005] In the process of surface nano-oxide dispersion strengthening and subsequent consolidation forming of high-strength and high-toughness aluminum alloy powder, it is difficult to avoid the formation of semi-continuous or connected oxide enrichment networks at the prior powder boundary while maintaining the powder's machinability and forming stability, and to achieve controllable transformation of oxides from the interfacial interlayer state to the intracrystalline non-connected dispersion state. Summary of the Invention

[0006] (a) Technical problems to be solved

[0007] To address the shortcomings of existing technologies, this invention provides a method for surface nano-oxide dispersion strengthening of high-strength and high-toughness aluminum alloy powder and its powder material. Using aluminum-zinc-magnesium-copper-zirconium pre-alloyed atomized powder as a matrix, magnesium-aluminum spinel nanoparticles, optional magnesium oxide nanoparticles, and passivated magnesium nanoparticles are sequentially introduced for dry coating via dispersion using polyvinylpyrrolidone and anhydrous alcohol. The nanoparticles are then embedded into the surface layer through ceramic ball micro-penetration. After vacuum segmental removal of organic matter, the powder is thermally activated at 405-435 degrees Celsius, cooled, and subsequently coated with low-energy zinc microparticles. This method reduces boundary connectivity, enhances densification, and significantly improves fracture toughness, impact resistance, and high-cycle fatigue resistance, thus solving the technical problems described in the prior art.

[0008] (II) Technical Solution

[0009] To achieve the above objectives, the present invention provides the following technical solution:

[0010] A high-strength, high-toughness aluminum alloy powder material includes component A, component B1, and component E1; component A is a pre-alloyed matrix powder atomized by inert gas, containing 5.8% to 7.4% zinc, 1.9% to 2.8% magnesium, 1.0% to 2.0% copper, 0.08% to 0.18% zirconium, and the balance being aluminum by mass percentage; component B1 is 0.05% to 0.30% magnesium-aluminum spinel nanoparticles based on the mass of component A; component E1 is 0.05% to 0.60% zinc micropowder based on the mass of component A; the powder particles have a plastic deformation layer with an average thickness of 0.2 to 1.0 micrometers on the surface, and at least 70% of the component B1 particles are centered within a range of 0.1 to 0.8 micrometers from the powder particle surface.

[0011] Furthermore, the particle size distribution of component A is D. 10 12 to 22 micrometers, median particle size D 50 25 to 45 micrometers, 90th percentile particle size D 90 The particle size is 50 to 80 micrometers, the maximum particle size is less than 100 micrometers, the sphericity is not less than 0.90, the proportion of satellite powder is not greater than 2%, the initial oxygen content is 0.16% to 0.20%, and the moisture content is not greater than 0.03%.

[0012] Furthermore, it also includes component B2, which is 0 to 0.15% magnesium oxide nanoparticles based on the mass of component A, and the mass ratio of component B1 to component B2 is 1:0 to 1:1.

[0013] Furthermore, the primary particle size of component B1 is 8 to 30 nanometers, the specific surface area is 40 to 160 square meters per gram, and the median particle size D of the aggregates after ultrasonic dispersion is... 50 No larger than 0.30 micrometers, with a purity of no less than 99.5%.

[0014] Furthermore, the purity of component E1 is not less than 99.9%, and the particle size is the median particle size D. 50 0.3 to 3.0 micrometers and 90th percentile particle size D 90 No larger than 6 micrometers.

[0015] A method for preparing the high-strength, high-toughness aluminum alloy powder material of claim 1, comprising:

[0016] Component D1 polyvinylpyrrolidone was dissolved in component D2 anhydrous isopropanol or anhydrous ethanol and then mixed with component A and vacuum dried; under an inert atmosphere, component B1 magnesium aluminum spinel nanoparticles and component C1 passivated magnesium nanoparticles were added to the dried powder for dry coating-friction compaction.

[0017] The powder and zirconia ceramic balls with a diameter of 0.3 to 0.8 mm were rolled for 20 to 35 minutes to achieve a subsurface embedding by micro-shot blasting. Subsequently, the vacuum was evacuated to an absolute pressure of no more than 50 Pa and thermally removed in stages at 300°C and 340 to 360°C. After thermal activation at 405 to 435°C, the powder was cooled to no more than 60°C. After cooling, component E1 zinc micro powder was added and subjected to low-energy coating or light embedding.

[0018] Furthermore, the weight-average molecular weight of component D1 is 10,000 to 40,000, and the amount used is 0.02% to 0.10% based on the mass of component A. The water content of component D2 is not greater than 0.2%. The vacuum drying is carried out at 60 degrees Celsius and an absolute pressure not greater than 500 Pa until the residual solvent is not greater than 0.02%.

[0019] Furthermore, the dry coating-friction compaction is carried out under the condition of passing high-purity argon gas, the oxygen content of which is not greater than 50 ppm; component B1 is added in two parts with an interval of 5 minutes between the two additions, and after mixing for 10 to 15 minutes, component C1 is added and mixed for 8 to 12 minutes; after cooling, component E1 is added and the shear strength is reduced and mixed for 6 to 10 minutes.

[0020] Furthermore, the segmented thermal removal involves a heating rate of 2 to 5 degrees Celsius per minute, followed by holding at 300 degrees Celsius for 30 to 60 minutes, then further heating to 340 to 360 degrees Celsius and holding for 30 to 90 minutes; the thermal activation is performed under vacuum or high-purity argon conditions and held for 20 to 45 minutes, wherein the oxygen content of the high-purity argon is no greater than 50 ppm.

[0021] Furthermore, the segmented thermal removal and thermal activation are carried out in a rotary tube furnace, a rotary kiln, or a closed vessel with a slow turning mechanism. When loading, the powder layer thickness is not greater than 20 mm or the powder bed heat transmission time is less than 5 minutes. The oxygen content of the atmosphere is not greater than 100 ppm and the dew point is not higher than -40 degrees Celsius. If agglomeration occurs, it is sieved with 63 microns after cooling to no higher than 80 degrees Celsius.

[0022] (III) Beneficial Effects

[0023] This invention provides a method for surface nano-oxide dispersion strengthening of high-strength and high-toughness aluminum alloy powder and the powder material thereof, which has the following beneficial effects:

[0024] By first constructing a synergistic reaction lattice of oxide seed sites and strongly oxygen-loving reactive components, and then using anchored dispersion components to achieve uniform positioning of nano-components, a subsurface embedded structure is formed on the surface of powder particles. This allows the film-breaking reaction and oxide nucleation to preferentially occur within the particles, promoting the transformation of oxides from an interfacial sandwich state to an intracrystalline non-connected dispersed nanoparticle state. This weakens the formation of continuous oxygen-rich networks and triangular agglomerations at the prior powder boundaries from the source. Through two-stage vacuum thermal activation to first remove dispersion residues and then trigger directional fragmentation and stabilization, secondary growth of the nanophase can be suppressed, and the obstacle of oxygen-containing interfaces to metallurgical bonding can be reduced.

[0025] Introducing transient zinc liquid bridge units post-processed and briefly wetting the interface during the densification stage accelerates interface healing and pore closure, while simultaneously blocking the reconnection of the oxygen-rich phase, reducing crack initiation pathways and minimizing batch variation. This reduces dependence on maximum thermal deformation while maintaining powder flowability and canning properties, resulting in higher density, continuous metallic bonding, and more stable microstructure evolution. The strength of the parts remains at a level consistent with precipitation strengthening, while fracture toughness, impact absorption capacity, and high-cycle fatigue life are synergistically improved. This enhances the service reliability and life assessment certainty of engineered parts, reducing non-destructive testing pressure and rework risks. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the overall process of the method of the present invention;

[0027] Figure 2 This is a schematic diagram of the micro-shot blasting subsurface embedding process / device of the present invention;

[0028] Figure 3 This is a schematic diagram of the cross-sectional structure of the powder particles of the present invention;

[0029] Figure 4 This is a temperature-time / process curve diagram of the two-stage vacuum thermal activation of the present invention. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Please see Figures 1-4 This invention provides a method for surface nano-oxide dispersion strengthening of high-strength and high-toughness aluminum alloy powder and the powder material thereof.

[0032] Component A: High-strength and high-toughness aluminum alloy matrix powder

[0033] A1 - Chemical composition (mass percentage, balance is aluminum)

[0034] Zinc: 5.8–7.4%;

[0035] Magnesium: 1.9–2.8%;

[0036] Copper: 1.0–2.0%;

[0037] Zirconium: 0.08–0.18% (used to form a dispersed aluminum-zirconium phase and improve recrystallization stability);

[0038] Manganese: 0.05–0.25% (optional, for stress corrosion resistance / improving toughness);

[0039] Chromium: 0–0.12% (optional);

[0040] Titanium: 0–0.08% (optional);

[0041] Iron ≤0.12%, silicon ≤0.10% (controlling brittle impurity phases);

[0042] A2 - Powder morphology and particle size;

[0043] Production method: Inert gas atomization (argon atomization is preferred);

[0044] Particle size distribution: D 10 12–22 micrometers; D 50 25–45 micrometers; D 90 50–80 micrometers; maximum particle size <100 micrometers;

[0045] Sphericity: ≥0.90; Satellite powder ratio ≤2%;

[0046] Inherent oxide layer on the surface: usually nanoscale (approximately several nanometers), which is a known inherent characteristic of powders.

[0047] Initial oxygen content (by mass fraction): 0.16–0.20%;

[0048] Moisture content (including adsorbed water): ≤0.03%;

[0049] Component B: Oxide seed lattice system;

[0050] B1-Magnesium aluminum spinel nanoparticles (MgAl2O4).

[0051] Primary particle size (transmission electron microscopy statistics): 8–30 nanometers;

[0052] Specific surface area: 40–160 square meters / gram;

[0053] Aggregate D 50 (Laser particle size, measured after ultrasonic dispersion): ≤0.30 micrometers;

[0054] Purity: ≥99.5%;

[0055] Dosage: 0.05–0.30% (based on the mass of powder A);

[0056] B2-magnesium oxide nanoparticles (optional reinforcing unit);

[0057] Primary particle size: 5–15 nanometers;

[0058] Specific surface area: 80–250 square meters / gram;

[0059] Dosage: 0–0.15% (based on the mass of powder A);

[0060] B1:B2 mass ratio: 1:0 to 1:1;

[0061] Component C: Sacrificial, strongly oxyphilic reaction unit;

[0062] C1-Magnesium Nanoparticles (Surface Passivated Type);

[0063] D 50 : 50–150 nanometers (preferably 70–100 nanometers);

[0064] Passivation layer thickness: 1–5 nanometers (a magnesium oxide / magnesium hydroxide composite layer to prevent spontaneous combustion at room temperature);

[0065] Active magnesium content: ≥90% (excluding passivation layer);

[0066] Dosage: 0.02–0.25% (based on the mass of powder A);

[0067] Component D: Anchored-dispersible-removable interfacial chemical unit;

[0068] D1-Polyvinylpyrrolidone;

[0069] Function: As a medium for dispersing and temporarily anchoring nanoparticles, it enables components B and C to form a uniform coating on the powder surface and inhibits agglomeration. At the same time, it can be removed in stages during the subsequent vacuum thermal removal process to reduce residue.

[0070] Weight-average molecular weight: 10,000–40,000;

[0071] Dosage: 0.02–0.10% (based on the mass of powder A);

[0072] D2 - Solvent carrier;

[0073] Solvent: Anhydrous isopropanol or anhydrous ethanol;

[0074] Water content: ≤0.2%. The amount used should be sufficient to form a uniform wet mixture, which needs to be completely removed under vacuum conditions afterward.

[0075] The organic matter removal temperature section uses segmented vacuum removal at 300–360°C, and a secondary removal is carried out in the degassing section of the canning process to reduce the adverse effects of residues on subsequent densification and heat treatment.

[0076] D3 - Anhydrous ethanol or anhydrous isopropanol (solvent carrier)

[0077] Water content: ≤0.2%;

[0078] Dosage: Use enough to form a flowable slurry / wet powder, which must eventually be completely removed.

[0079] Component E: Transient zinc liquid bridge unit;

[0080] E1-Zinc Micro Powder

[0081] Purity: ≥99.9%;

[0082] Particle size: D 50 0.3–3.0 micrometers; D 90 ≤6 micrometers;

[0083] Dosage: 0.05–0.60% (based on the mass of powder A)

[0084] IV. Examples

[0085] The following description is based on 10 kg of Powder A as a batch (the scale can be adjusted proportionally to the enlarged or reduced size).

[0086] 1) Example formulation (weight basis: based on 10000 grams of powder A)

[0087] A (pre-alloyed atomized powder): 10000 grams;

[0088] Example composition (by mass percentage): Zinc 6.5%, Magnesium 2.3%, Copper 1.5%, Zirconium 0.12%, Manganese 0.10%, Balance Aluminum; Iron ≤0.10%, Silicon ≤0.08%.

[0089] Particle size: D 50 Approximately 35 micrometers, D 90 Approximately 70 micrometers.

[0090] B (oxide seed lattice) Total: 18 grams (0.18%)

[0091] B1 (MgAl2O4 nanoparticles): 12 g (0.12%), primary particle size approximately 15 nm, specific surface area approximately 90 m² / g;

[0092] B2 (MgO nanoparticles): 6 g (0.06%), primary particle size approximately 8 nanometers, specific surface area approximately 160 m² / g.

[0093] C (magnesium nanoparticles): 10 g (0.10%)

[0094] D 50 Approximately 80 nanometers, with a passivation layer thickness of approximately 2–3 nanometers.

[0095] D (dispersed system);

[0096] D1 (polyvinylpyrrolidone, weight average molecular weight 10,000–40,000): 6 g (0.06%).

[0097] D2 (anhydrous isopropanol or anhydrous ethanol): approximately 1.5–2.5 liters (enough to form a homogeneous wet mixture);

[0098] D3 (anhydrous ethanol): approximately 1.5–2.5 liters (enough to form a homogeneous wet mixture);

[0099] E (zinc micro powder): 35 grams (0.35%); D 50 Approximately 0.8 micrometers, D 90 The zinc micropowder, ≤3 micrometers, is introduced after thermal activation and cooling in step S4, and is treated by low-energy coating or light embedding to avoid premature bonding during the thermal activation heating stage.

[0100] 2) Preparation method

[0101] Step S0: Pre-drying of powder A and environmental control;

[0102] Place 10,000 grams of powder A into a stainless steel tray or roller container with an inert gas inlet.

[0103] Evacuate the vacuum oven to an absolute pressure of ≤200 Pa, then heat to 110°C and hold for 4 hours;

[0104] After cooling to ≤40°C, high-purity argon gas is introduced to backfill to atmospheric pressure, and the mixture is sealed and transferred to an inert atmosphere environment (such as a glove box or an inert gas protected powder mixing chamber).

[0105] Control objective: To prevent the introduction of moisture into the D system in the subsequent process, which could lead to secondary hydration / oxidation of the powder.

[0106] Step S1: Anchoring treatment of system D (forming a controllable surface chemical layer)

[0107] Under an inert atmosphere, add 2.0 liters of anhydrous isopropanol or anhydrous ethanol to a sealed stirred tank.

[0108] Add 6 grams of polyvinylpyrrolidone and stir until completely dissolved and a homogeneous solution is formed;

[0109] Slowly add the pre-dried powder A into the mixing vessel and keep stirring for 30–45 minutes to ensure that the dispersant uniformly wets the powder and provides an adsorption and dispersion environment for subsequent nano-components.

[0110] The solvent is removed by vacuum filtration or reduced pressure rotary evaporation to obtain a dispersed wet powder;

[0111] Dry the wet powder at 60°C and absolute pressure ≤500 Pa for 6–10 hours until the quality is constant (with the goal of residual solvent ≤0.02%).

[0112] Step S2: Dry coating - friction compaction (transforming random agglomeration of B, C, and E into uniform decoration)

[0113] Use dry powder mixing / mechanical fusion equipment with strong shearing and frictional compaction capabilities (no specific model is limited).

[0114] The dry powder obtained from S1 is fed into the equipment and high-purity argon gas (oxygen content ≤50ppm is preferred).

[0115] First add B1+B2: add in two batches (5 minutes apart each time), mix at a high shear strength for 10–15 minutes to spread the nano-oxide evenly;

[0116] Then add C1: continue mixing for 8–12 minutes to allow the magnesium nanoparticles to preferentially approach the B enrichment region (where the anchoring layer of D provides adsorption sites).

[0117] After discharge, samples were taken and observed using a scanning electron microscope: the nanophase should not have agglomerates larger than 5 micrometers, and the zinc powder should not form obvious cold welds.

[0118] The preferred activation furnace type is a rotary tube furnace, a rotary kiln, or a closed vessel with a slow turning mechanism, so that the powder is continuously loosened and turned during the heating and holding stages; the powder layer thickness should not exceed 20 mm or the powder bed heat transmission time should be less than 5 min; the atmosphere should be controlled so that the oxygen content is not greater than 100 ppm and the dew point is not higher than -40℃; if slight agglomeration still occurs, the agglomerates can be removed by sieving with a 63 μm sieve after cooling to no higher than 80℃.

[0119] Step S3: Micro-jet shot blasting subsurface embedding

[0120] Objective: To advance the B / C composite lattice from surface attachment to the subsurface plastic deformation layer, so that it can naturally enter the grain during subsequent densification, instead of remaining at the PPB interface.

[0121] One possible implementation method:

[0122] In an inert atmosphere, S2 powder and zirconia ceramic balls (0.3–0.8 mm in diameter) are loaded into a sealed drum at a ball:powder mass ratio of 0.15:1.

[0123] Roll the powder at a drum speed of 80–140 rpm for 20–35 minutes, during which the powder temperature should be controlled to be ≤45°C.

[0124] After completion, the ceramic balls were separated by sieving to obtain a subsurface embedded composite powder.

[0125] Average thickness of the plastic deformation layer on the powder surface: 0.2–1.0 micrometers;

[0126] Burial depth distribution of B / C particles: At least 70% of the B / C particles are centered within 0.1–0.8 micrometers from the surface (based on cross-sectional sample preparation statistics).

[0127] The powder remains nearly spherical: the sphericity decreases by no more than 0.03; D 50 The variation shall not exceed ±5 micrometers.

[0128] Detection and statistical methods: Powder particle cross-sections were prepared by focused ion beam slicing, and elemental distribution and particle identification were performed on the cross-sections by scanning electron microscopy-energy dispersive spectroscopy or transmission electron microscopy. No less than 30 powder particles were randomly selected, and the center embedment depth of no less than 20 nanoparticles in each particle cross-section was statistically analyzed. The proportion of particles that meet the embedment depth range was calculated to determine the embedding effect.

[0129] Step S4: Two-stage vacuum thermal activation (first remove D, then induce directional spinelization and break the film)

[0130] The S3 powder is loaded into a vacuum heat treatment furnace (or rotary vacuum furnace) that can slowly tumble, and air is prevented from entering throughout the process.

[0131] Section 1: Segmented vacuum removal of organic residues

[0132] Vacuum the powder to an absolute pressure of ≤50 Pa and slowly tumble it to keep the powder loose.

[0133] Increase the temperature to 300°C at a rate of 2–5°C / min, hold for 30–60 minutes, then continue to increase the temperature to 340–360°C and hold for 30–90 minutes to promote the gradual discharge of the dispersant and its decomposition products under vacuum.

[0134] After the first stage is completed, the furnace is cooled or the temperature is lowered to no more than 100°C before entering the second stage of thermal activation or being removed from the furnace and transferred.

[0135] The subsequent degassing section can be subjected to secondary vacuum removal at approximately 350°C to further reduce the impact of organic residues on densification and heat treatment.

[0136] Step S5: Finally, add E1 zinc micro powder.

[0137] Reduce shear strength and mix for 6–10 minutes to avoid excessive cold welding and agglomeration of zinc micropowder.

[0138] Second section: Directional membrane breaking and spinel thermal activation;

[0139] Under the same vacuum or high-purity argon (oxygen ≤50ppm) conditions, the temperature is raised to 405–435°C and held for 20–45 minutes; this causes the surface oxide film to rupture and transform into discrete spinel-like nano-oxides under the action of the reaction lattice.

[0140] After being cooled to ≤60°C in the furnace, the product is removed from the furnace and packaged in an inert atmosphere.

[0141] The final powder material obtained is: subsurface embedded nano-oxide lattice reinforced high-strength and high-toughness aluminum alloy powder.

[0142] During the thermal activation process, the powder is kept loose by slow tumbling or rotation to inhibit agglomeration and sintering neck growth; then it is cooled in the furnace to no higher than 60°C and transferred and packaged in an inert atmosphere, proceeding to step S5.

[0143] 3) Factory specifications for powder materials

[0144] The loose packing density and flowability (Hall flow rate or alternative indicators) meet the requirements for powder metallurgy canning / filling;

[0145] The increase in oxygen content relative to powder A: 0.02–0.12% (derived from the reaction of powder B with nano-oxides).

[0146] Oxide / nanophase aggregates larger than 10 micrometers are not allowed (based on microscopic statistics).

[0147] The powder did not exhibit significant agglomeration or clumping (verified by sieving recovery or flowability).

[0148] I. 5 groups of experimental groups

[0149] Shared raw materials (consistent across all groups)

[0150] Matrix powder A: Gas-atomized high-strength, high-toughness Al–Zn–Mg–Cu pre-alloyed powder, particle size 15–63 microns, D 50 Approximately 35 micrometers, sphericity ≥0.90; initial oxygen content (mass fraction) of powder approximately 0.16%–0.20% (typically due to the oxide film on the surface of gas-atomized aluminum powder). Subsequent densification and heat treatment: Except for the powder surface treatment step, the canning / degassing / HIP / extrusion / heat treatment of all groups are completely consistent.

[0151] Group:

[0152] G1 | Comparative Example 1 (Baseline): Powder A only → Conventional degassing → Hot isostatic pressing → Hot extrusion → T6 heat treatment.

[0153] G2 | Comparative Example 2: A powder + nano alumina simple decoration (e.g., 0.10%–0.20% mass fraction γ-alumina, particle size 20–50 nm), which is attached to the surface only by dry / wet mixing, without embedding, reduction / conversion pre-activation, or introduction of transient eutectic phase.

[0154] G3 | Comparative Example 3 (semi-improved: with reduction / conversion units, but no embedding): Powder A + (seed nanoparticles B + reduction / conversion components C + dispersion / temporary binder components D), but the process only achieves surface adsorption / coverage, without implementing the key subsurface embedding (propelling nanoparticles 10–50 nm below the surface); the rest of the thermal activation is performed as before.

[0155] G4 | Comparative Example 4 (semi-improved: with embedding, but without transient eutectic phase E): A powder + B + C + D, and embedding is performed, and thermal activation is also performed; but E (zinc-enriched transient eutectic phase / wetting phase unit) is not added.

[0156] G5 | Example 1 (Scheme of this application): A powder + B + C + D + E, and perform embedding and segmented thermal activation. After cooling, E is introduced and subjected to low-energy coating or light embedding. Subsequently, densification and plastic deformation are carried out to promote the dispersion of oxide fragments into the crystal. Component E is introduced after embedding and segmented thermal activation and cooling.

[0157] Target structure: Instead of forming semi-continuous oxide interlayers / networks at PPB, the structure is dominated by intracrystalline non-connected nano-oxide / spinel particles, thereby achieving high strength, high toughness and high fatigue resistance.

[0158] II. Standardized Processing Routes

[0159] (1) Powder filling and degassing (general purpose of five groups)

[0160] The processed powder is placed into an aluminum alloy or low-carbon steel container and then filled with high-purity argon gas for protection.

[0161] Vacuum degassing: 350℃ for 4 hours, vacuum degree ≤5×10⁻² Pa; seal after cooling.

[0162] (2) Hot isostatic pressing and hot extrusion (general for all five groups)

[0163] Hot isostatic pressing (HIP): 450℃ × 3 hours, pressure 120 MPa.

[0164] Hot extrusion: Extrusion temperature 390–410℃, extrusion ratio 10:1 (or higher), to obtain bar / sheet blanks.

[0165] (3) Heat treatment (general for all five groups: T6 example)

[0166] Solution treatment: 465℃ for 1 hour → water quenching.

[0167] Artificial aging: 120℃ × 24 hours.

[0168] III. Test Items and National Standards Adopted

[0169] Powder properties:

[0170] Hall effect flow rate (flowability): GB / T1482-2022.

[0171] Loose packing density: GB / T1479.1-2011.

[0172] Tap density: GB / T5162-2021.

[0173] General rules for analysis of hydrogen / oxygen / nitrogen / carbon / sulfur gases (for oxygen content, etc.): GB / T14265-2017.

[0174] Block / Product Performance

[0175] Room temperature tensile strength: GB / T228.1-2021.

[0176] Vickers hardness: GB / T4340.1-2024.

[0177] Charpy pendulum impact: GB / T229-2020.

[0178] Fracture toughness (KIC): GB / T4161-2007.

[0179] High-cycle fatigue (axial force control): GB / T3075-2021.

[0180] Density of dense sintered materials (Archimedes process system): GB / T3850-2015.

[0181] IV. Sexuality Test Data (5 Groups of Comparison)

[0182]

[0183]

[0184] Sample preparation: Sampling, mounting, grinding and polishing were carried out in accordance with GB / T13298-2015 to ensure that the cross section was free from pull-out and scratches; For aluminum alloy materials, both appropriate corrosion and non-corrosion methods can be used to obtain comparative images, with non-corrosion backscattered electron imaging preferred to enhance phase contrast.

[0185] Microscopic acquisition: Cross-sectional images are acquired using backscattered electron mode under a scanning electron microscope, and energy dispersive spectroscopy surface scan or spot scan is performed simultaneously in the same field of view to confirm the oxygen-rich phase; a magnification range of 1,000 to 5,000 times is recommended to ensure that the oxide phase and the matrix can be stably distinguished in terms of grayscale and elemental distribution.

[0186] PPB identification rules: The interface in the material corresponding to the original powder profile is taken as the prior powder boundary, and its identification can be based on at least one of the following criteria:

[0187] Continuous or semi-continuous oxygen-rich phases, inclusion phases, or pore chains appear at the interface;

[0188] The contrast abrupt change is caused by differences in tissue orientation or micro-segregation of components on both sides of the interface;

[0189] Even after stitching together multiple fields of view of the same area, the grain outline still appears as closed or semi-closed.

[0190] Oxide phase identification rules: The phase confirmed by the energy spectrum to be oxygen-rich is identified as the oxide phase, and a binary threshold is established based on the gray range of the phase in the backscattered image. The threshold should be based on the gray statistics of no less than three energy spectrum verification points in the same batch of samples, and should be consistent throughout the entire batch.

[0191] Determination of "continuous segment": In the direction of PPB busbar, if the gap between adjacent oxide segments is less than or equal to the preset breakpoint length, they are considered as the same continuous segment; the breakpoint length is recommended to be one to three micrometers, or several times the size of the next pixel after statistical magnification, in order to ensure the consistency of determination for different fields of view.

[0192] Length statistics and sampling: The total length of the PPB was measured along the PPB generatrix in each field of view using image analysis software. The sum of the lengths of the continuous segments covered by oxide phases was measured. Define the PPB oxide connectivity fraction as For each sample, at least ten fields of view are randomly selected, and the total length of the cumulative PPB is not less than 20 mm; at least three parallel samples are prepared, the average value is taken, and the standard deviation is given.

[0193] If the relative deviation of fff is greater than 10 percent when the same sample is repeatedly counted by different operators or on different dates, the threshold setting and PPB identification rules should be rechecked until the consistency requirements are met.

[0194] V. Conclusion

[0195] Comparative Example 2 (G2):

[0196] Compared to G1, G2 exhibits slightly increased yield strength and tensile strength (approximately +20 MPa), but decreased fracture toughness (KIC) (18→14), decreased fatigue strength (130→115), and lower elongation. Decorative particles are more likely to form rings / networks at the prior powder boundaries in the early stages of compaction / sintering, becoming pathways for rapid crack propagation.

[0197] Comparative Examples 3 and 4 (G3, G4):

[0198] G3 (non-intercalated) showed a significant increase in KIC and fatigue compared to G1 (18→22; 130→155), indicating that the reduction / conversion unit can indeed disrupt part of the oxide film continuity.

[0199] G4 (with embedded but no transient eutectic phase E) is further improved (KIC24, fatigue 165), indicating that pushing nanounits into the subsurface can more effectively strip and remove oxides from the boundary, and the PPB connectivity length fraction decreases to about 0.25.

[0200] However, G4 is still significantly lower than G5, indicating that oxide fragments may still aggregate again near the boundary by relying solely on embedding and solid-state diffusion, making it difficult to maximize intracrystalline non-connected dispersion.

[0201] Example 1 (G5):

[0202] Compared to G4, G5 has only an increase of about +15 MPa in tensile strength (600→615), but its elongation after fracture jumps (8.0→10.5), KIC increases significantly (24→27), fatigue strength increases significantly (165→185), and PPB connectivity decreases from 0.25 to 0.08.

[0203] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0204] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0205] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0206] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0207] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A high-strength, high-toughness aluminum alloy powder material, characterized in that: The product comprises components A, B1, C1, and E1. Component A is a pre-alloyed matrix powder atomized by an inert gas, containing, by mass percentage, 5.8% to 7.4% zinc, 1.9% to 2.8% magnesium, 1.0% to 2.0% copper, 0.08% to 0.18% zirconium, with the balance being aluminum. Component B1 consists of 0.05% to 0.30% magnesium-aluminum spinel nanoparticles based on the mass of component A. Component E1 consists of 0.05% to 0.60% zinc micropowder based on the mass of component A. The surface of the pre-alloyed matrix powder particles has a plastic deformation layer with an average thickness of 0.2 to 1.0 micrometers, and at least 70% of the center of component B1 particles is located within 0.1 to 0.8 micrometers from the powder particle surface. The purity of component E1 is not less than 99.9%, and the particle size is a median particle size D. 50 0.3–3.0 micrometers and 90th percentile particle size D 90 No larger than 6 micrometers; C1 is surface-passivated magnesium nanoparticles, added at 0.02%–0.25% of the mass of component A, with a median particle size D. 50 The thickness is 50-150 nanometers, the passivation layer thickness is 1-5 nanometers, and the active magnesium content is not less than 90%.

2. The powder material according to claim 1, characterized in that: The particle size distribution of component A is D 10 12 to 22 micrometers, median particle size D 50 25 to 45 micrometers, 90th percentile particle size D 90 The particle size is 50 to 80 micrometers, the maximum particle size is less than 100 micrometers, the sphericity is not less than 0.90, the proportion of satellite powder is not greater than 2%, the initial oxygen content is 0.16% to 0.20%, and the moisture content is not greater than 0.03%.

3. The powder material according to claim 1 or 2, characterized in that: It also includes component B2, which is 0 to 0.15% magnesium oxide nanoparticles based on the mass of component A, and the mass ratio of component B1 to component B2 is 1:0 to 1:

1.

4. The powder material according to claim 3, characterized in that: Component B1 has a primary particle size of 8 to 30 nanometers and a specific surface area of ​​40 to 160 square meters per gram. The median particle size D of the aggregates after ultrasonic dispersion is... 50 No larger than 0.30 micrometers, with a purity of no less than 99.5%.

5. A method for preparing the high-strength, high-toughness aluminum alloy powder material according to claim 1, characterized in that: include: Component D1 polyvinylpyrrolidone was dissolved in component D2 anhydrous isopropanol or anhydrous ethanol, then mixed with component A and vacuum dried. Under an inert atmosphere, component B1 magnesium aluminum spinel nanoparticles were first added to the dried powder and mixed, and then component C1 surface passivated magnesium nanoparticles were added for dry coating-friction compaction. The powder and zirconia ceramic balls with a diameter of 0.3 to 0.8 mm were rolled at a ball:powder mass ratio of 0.15:1 for 20 to 35 minutes for micro-shot blasting subsurface embedding. Then, the vacuum was drawn to an absolute pressure of no more than 50 Pa and thermally removed in stages at 300 degrees Celsius and 340 to 360 degrees Celsius. After thermal activation at 405 to 435 degrees Celsius, the temperature was cooled to no more than 60 degrees Celsius. After cooling, add component E1 zinc micro powder and perform low-energy coating or light embedding.

6. The method according to claim 5, characterized in that: The weight-average molecular weight of component D1 is 10,000 to 40,000, and the amount used is 0.02% to 0.10% based on the mass of component A. The water content of component D2 is not greater than 0.2%. The vacuum drying is carried out at 60 degrees Celsius and an absolute pressure not greater than 500 Pa until the residual solvent is not greater than 0.02%.

7. The method according to claim 6, characterized in that: The dry coating-friction compaction is carried out under the condition of passing high-purity argon gas, the oxygen content of which is not greater than 50 ppm; component B1 is added in two parts with an interval of 5 minutes between the two additions, and after mixing for 10 to 15 minutes, component C1 is added and mixed for 8 to 12 minutes.

8. The method according to claim 7, characterized in that: The segmented thermal removal process involves heating at a rate of 2 to 5 degrees Celsius per minute, holding at 300 degrees Celsius for 30 to 60 minutes, then further heating to 340 to 360 degrees Celsius and holding for 30 to 90 minutes. The thermal activation is performed under vacuum or high-purity argon conditions and held for 20 to 45 minutes. The oxygen content of the high-purity argon is no more than 50 ppm.

9. The method according to any one of claims 5 to 8, characterized in that: The segmented thermal removal and thermal activation are carried out in a rotary tube furnace, rotary kiln, or a closed vessel with a slow turning mechanism. When loading, the powder layer thickness is not greater than 20 mm or the powder bed heat transmission time is less than 5 minutes. The oxygen content of the atmosphere is not greater than 100 ppm and the dew point is not higher than -40 degrees Celsius. If agglomeration occurs, it is sieved with 63 microns after cooling to no higher than 80 degrees Celsius.

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