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CN-121972654-A - High-fluidity aluminum alloy powder for additive manufacturing and preparation method thereof

CN121972654ACN 121972654 ACN121972654 ACN 121972654ACN-121972654-A

Abstract

The invention discloses high-fluidity aluminum alloy powder for additive manufacturing and a preparation method thereof, and relates to the technical field of additive manufacturing powder, comprising the following contents that A1 prealloyed aluminum-silicon-magnesium spherical powder is taken as a matrix, a C1 nitrogen-containing aluminum oxide or oxygen-nitrogen chemical surface layer is formed on the surface, the thickness is 2 to 8 nanometers, and N/(N+O) is 0.10 to 0.35; and a layer B is anchored on the surface of C1 by dry method and strong shearing, B consists of B1 titanium diboride nano particles and B2 titanium nitride nano particles, and E1 porous micro-agglomerates consisting of B1 and B2 are introduced, and D1 aluminum magnesium master alloy powder with the surface of C1 is optionally added. The preparation method comprises the steps of fluidized bed non-thermal plasma treatment, solid phase composite anchoring and spray drying to prepare E1, mixing, and maintaining stable flow and spreading after repeated recovery, screening and multiplexing of the powder, reducing the defects of water-containing oxygen-containing drift and powder spreading, improving the density and reducing the porosity and the performance dispersion.

Inventors

  • LI DAISHUI
  • XIANG WENGAI
  • LI DAIQUAN
  • YANG LING
  • TANG YUNSONG

Assignees

  • 湖南金昊新材料科技股份有限公司

Dates

Publication Date
20260505
Application Date
20260409

Claims (10)

  1. 1. The high-fluidity aluminum alloy powder for additive manufacturing is characterized by comprising, The porous aluminum silicon magnesium alloy comprises an A1 prealloyed aluminum silicon magnesium spherical powder, a C1 nitrogenous aluminum oxide or oxynitride chemical state surface layer covered on the surface of the A1, an average thickness of 2 to 8 nanometers, N/(N+O) of 0.10 to 0.35 and coverage rate of not less than 90%, a B layer fixed on the surface of the C1, wherein the B layer consists of B1 titanium diboride nano particles and B2 titanium nitride nano particles, the mass fraction of the B is 0.03 to 0.12 percent, the mass ratio of the B1 to the B2 is 2:1 to 10:1, and an E1 porous micro-aggregate, E1 consists of B1 and B2, the mass fraction of the E1 is 0.01 to 0.08 percent, the porosity is 40 to 70 percent, the D50 is 5 to 20 micrometers and the D90 is not more than 30 micrometers.
  2. 2. The high-fluidity aluminum alloy powder as claimed in claim 1, wherein: The chemical composition of A1 comprises 9.0 to 11.0 percent of silicon, 0.20 to 0.55 percent of magnesium, not more than 0.50 percent of iron, not more than 0.45 percent of manganese, not more than 0.10 percent of copper, not more than 0.10 percent of zinc, not more than 0.15 percent of titanium, and the balance of aluminum and unavoidable impurities.
  3. 3. The high-fluidity aluminum alloy powder as claimed in claim 1, wherein: the particle size distribution of A1 is 15 to 63 microns, D10 is 18 to 24 microns, D50 is 34 to 40 microns, D90 is 55 to 63 microns, the mass fraction of fine powder smaller than 15 microns is not more than 2.0%, the mass fraction of coarse powder larger than 63 microns is not more than 0.2%, the sphericity is not less than 0.93, and the satellite powder or adhesion particle proportion is not more than 0.5%.
  4. 4. The high-fluidity aluminum alloy powder as claimed in claim 1, wherein: The D50 of the B1 titanium diboride nano-particles is 40 to 120 nanometers and the specific surface area is 15 to 35 square meters per gram, the D50 of the B2 titanium nitride nano-particles is 10 to 30 nanometers and the specific surface area is 30 to 80 square meters per gram, and the coverage rate of the nano-particles of the B layer is kept to be not lower than 60 percent after the nano-particles are subjected to absolute ethyl alcohol ultrasonic treatment for 10 minutes.
  5. 5. The high-fluidity aluminum alloy powder as claimed in claim 1, wherein: c1 has an average thickness of 3 to 6nm and N/(N+O) of 0.15 to 0.25.
  6. 6. The high-fluidity aluminum alloy powder as claimed in claim 1, wherein: Also comprises D1 aluminum magnesium master alloy powder, wherein the mass fraction of magnesium in D1 is 25-40%, the granularity of D1 is 10-45 micrometers and the D50 is 20-30 micrometers, the mass fraction of D1 is 0.10-0.60%, and the surface of D1 is covered with a C1 nitrogenous alumina or oxynitride chemical surface layer with the average thickness of 2-8 nanometers.
  7. 7. The high-fluidity aluminum alloy powder as claimed in claim 1, wherein: the mass ratio of B1 to B2 in E1 is 7:3, D50 of E1 is 8-15 microns and D90 is not more than 25 microns, and the mass fraction of E1 is 0.02-0.05%.
  8. 8. The preparation method of the high-fluidity aluminum alloy powder for additive manufacturing is characterized by comprising the following steps of: Preparing A1 prealloyed aluminum-silicon-magnesium spherical powder and drying; treating A1 in a fluidized bed type non-thermal plasma reactor by fluidizing with nitrogen and introducing a trace oxygen source, wherein the trace oxygen source is oxygen or nitrous oxide, to form a C1 nitrogenous alumina or an oxygen nitrogen chemical surface layer with an average thickness of 2 to 8 nanometers and N/(N+O) of 0.10 to 0.35; Adding B1 titanium diboride nano particles and B2 titanium nitride nano particles into the A1 treated in the step S2 under inert atmosphere, and carrying out dry method strong shearing solid phase composition to enable the B1 and the B2 to be semi-embedded and fixed on the surface of the C1 to form a B layer; Preparing an E1 porous micro-aggregate formed by B1 and B2 by adopting a spray drying method; the treated powder was low shear blended with E1 and sieved to obtain the final powder.
  9. 9. The method of manufacturing according to claim 8, wherein: Step S3 includes two-stage energy input, the first stage mixing at 2000 to 3500 rpm for 8 to 15 minutes and the second stage mixing at 4000 to 6000 rpm for 2 to 8 minutes, with the mixing chamber wall temperature being controlled to be no higher than 45 degrees celsius.
  10. 10. The method of manufacturing according to claim 9, wherein: preparing a dispersion liquid of B1 and B2 in the step S4, wherein the solid content is 2-6%, adding ammonium bicarbonate as a pore-forming agent and enabling the dosage of the ammonium bicarbonate to be 10-40% of the mass of the nano particles, spray-drying at the inlet temperature of 120-160 ℃ and at the outlet temperature of 60-90 ℃, drying at 100-120 ℃ for 2-4 hours under vacuum after collection to obtain E1, adding D1 aluminum magnesium master alloy powder, mixing for 10-20 minutes, adding E1, mixing for 5-15 minutes, and lightly sieving once by using a 63-micrometer sieve.

Description

High-fluidity aluminum alloy powder for additive manufacturing and preparation method thereof Technical Field The invention relates to the technical field of additive manufacturing powder, in particular to high-fluidity aluminum alloy powder for additive manufacturing and a preparation method thereof. Background Powder bed molten metal additive manufacturing (e.g., laser powder bed melting) has been used in the aerospace, automotive lightweight, and thermal management fields to manufacture thin-walled heat exchangers, complex runner cold plates, manifolds, topologically optimized brackets, and other aluminum alloy components. The components are generally thin in wall thickness, thin in runner and high in structural integration degree, powder layers with the thickness of about 20-60 microns are continuously paved in inert atmosphere by a scraper or a roller in the forming process, and the flowability, spreadability and powder bed stacking density of the powder directly influence the energy coupling of a molten pool, interlayer metallurgical bonding and size consistency. In the current industry, the gas atomization spherical aluminum-silicon-magnesium alloy powder (such as aluminum-silicon-magnesium system) is commonly adopted, and is matched with the particle size classification and screening recovery, so as to meet the requirements of mass production on the powder supply stability and the material cost. In actual production, powder is often subjected to multiple construction cycles in a forming cabin of equipment, namely, the unmelted powder is recovered, larger splashes are removed through screening, and then the powder is mixed with new powder in a certain proportion or is directly reused, and batch control is carried out through indexes such as funnel flowability, apparent/tap density, particle size distribution, oxygen-containing water and the like. In order to reduce process fluctuation, the prior art is often combined with measures such as drying, inert atmosphere maintenance, limitation of multiplexing times and the like. However, since the powder spreading process is dynamic shearing spreading and the powder continuously evolves under the combined action of air flow, heat radiation and mechanical friction, the conventional index and the consistency of the actual powder spreading may deviate, so that the powder still may have the abnormality of powder bed stripes, partial powder shortage or powder piling although the powder meets the static inspection threshold. The aluminum alloy powder has a natural oxide film and is sensitive to trace moisture and oxygen partial pressure, and can be exposed to a composite environment of high temperature gradient, splash fall-back and evaporation-condensation fine particles in the repeated construction, recovery, transportation and screening processes. The method can cause the aggravation of surface oxidation/hydroxylation, the selective oxidation or volatilization of active elements such as magnesium and the like, the increase of the proportion of satellite powder and agglomerates, the change of surface roughness and charge state, and further increase of inter-particle van der Waals force, capillary bridging force and electrostatic adsorption force, so that the powder is converted from a low cohesive state to a high cohesive state, and the fluidity and spreadability drift along with circulation. If the drift cannot be effectively controlled, interlayer fluctuation is generated in the thickness and the density of the powder bed, and the defect melting pores, inclusions and interlayer combination are easily induced to be unstable, so that key performances such as density, elongation, fatigue life and the like are discretely increased, and the cost and risk of batch consistency evaluation and quality authentication are increased. Therefore, the technical problem to be solved in the prior art is that the mobility and powder laying consistency drift of the aluminum alloy powder caused by the evolution of the surface chemical state and morphology particle composition is difficult to be controlled stably under the working condition of repeated recovery and reuse of the powder bed melting additive manufacturing. Disclosure of Invention Aiming at the defects of the prior art, the invention provides high-fluidity aluminum alloy powder for additive manufacturing and a preparation method thereof, wherein A1 prealloyed aluminum-silicon-magnesium spherical powder is used as a matrix, a C1 nitrogenous alumina or oxygen-nitrogen chemical state surface layer is formed on the surface, the thickness is 2 to 8 nanometers, N/(N+O) is 0.10 to 0.35, a B layer is anchored by dry method strong shearing on the surface of C1, B consists of B1 titanium diboride nano particles and B2 titanium nitride nano particles, porous micro-agglomerates formed by B1 and B2 are introduced, D1 aluminum-magnesium master alloy powder with C1 on the surface is optionally added, the powder keeps stable flow an