CN-122013001-A - Intra-crystal dispersion strengthening type aluminum magnesium alloy and preparation method thereof

Abstract

The invention discloses an intragranular dispersion strengthening type aluminum magnesium alloy and a preparation method thereof, and relates to the technical field of metal and composite material preparation. The aluminum magnesium alloy prepared by the invention has a double-peak crystal grain structure of submicron crystal and micron crystal, and dispersed nano oxides exist in the submicron crystal, and the nano oxides comprise one or more of MgO and Al 2 O 3 、Al 4 O 4 C、MgAl 2 O 4 . The nano dispersion oxide is favorable for exciting Orowan reinforcement, and avoids the premature cracking of a grain boundary and a submicron crystal/micron crystal heterogeneous interface through mechanisms such as back stress hardening and the like, and fully exerts the plasticizing effect of the micron coarse crystal.

Inventors

• TAN ZHANQIU
• GUO ZHIQI
• FAN GENLIAN
• LI ZHIQIANG
• ZHANG DI

Assignees

• 上海交通大学

Dates

Publication Date

20260512

Application Date

20260129

Claims (10)

1. 1. The crystal grain dispersion strengthening type aluminum magnesium alloy is characterized in that a matrix comprises first crystal grains and second crystal grains, the average size difference of the first crystal grains and the second crystal grains is larger than 400nm, the first crystal grains are submicron crystals, dispersed nano oxides exist in the submicron crystals, and the volume fraction of the nano oxides is 3-8 vol.%.
2. 2. The aluminum magnesium alloy according to claim 1, comprising at least one of the following technical characteristics: A1, the nano oxide is one or more of MgO and Al 2 O 3 、Al 4 O 4 C、MgAl 2 O 4 ; and B1, the average particle size of the nano oxide is 3-100 nm.
3. 3. The aluminum-magnesium alloy according to claim 1, wherein the second type of crystal grains are microcrystals, the equivalent size of the submicron crystals is 0.1-1 μm, the equivalent size of the microcrystals is 2-20 μm, and the mass ratio of the submicron crystals to the microcrystals is 7-8:2-3.
4. 4. A method of preparing an aluminium magnesium alloy according to any one of claims 1 to 3, comprising the steps of: Weighing a first raw material and a second raw material according to parts by weight: The aluminum powder and the aluminum alloy powder are 0-100 parts, 0-30 parts, 1-5 parts and 1 part of nano ceramic powder, wherein the aluminum powder and the aluminum alloy powder are not 0 at the same time; the second raw material comprises 5-30 parts of aluminum-containing powder; s2, mixing the first raw materials to obtain mixed powder A; s3, performing ball milling treatment on the mixed powder A for the first time to obtain mixed powder B; S4, performing secondary ball milling treatment on the mixed powder B to obtain mixed powder C1; S5, carrying out vacuum heating treatment on the mixed powder C1, wherein the vacuum degree is 5-50 Pa, and the heating temperature is 350-400 ℃ for 0.5-3 hours to obtain mixed powder C2; s6, performing ball milling treatment on the mixed powder C2 for the third time to obtain mixed powder C3, and mixing the mixed powder C3 with a second raw material to obtain mixed powder C4; s7, performing ball milling treatment on the mixed powder C4 for the fourth time to obtain mixed powder D; and S8, pressing the mixed powder D into an ingot blank, sintering the ingot blank, performing thermal deformation processing and cooling treatment to obtain the aluminum-magnesium alloy.
5. 5. The method of claim 4, wherein the nanoceramic powder is one or more of carbon nanotubes, carbon nanospheres, carbon nanofibers, carbon nanoplatelets, graphene oxide, diamond, siC, B 4 C、AlN、Al 2 O 3 、Cu x O y , znO.
6. 6. The preparation method according to claim 4, comprising at least one of the following technical features: a3, the second raw material is aluminum powder and/or aluminum magnesium alloy powder, and the granularity is 1-100 mu m; and B3, when the second raw material is aluminum magnesium alloy powder, the mass fraction of Mg is 3.0% -10%.
7. 7. The method according to claim 4, wherein the aluminum alloy powder contains one or more of Si, fe, mn, ni, ti, cr, co, nb, W, and the mass fraction of Al in the aluminum alloy powder is 99.0% or more.
8. 8. The method according to claim 4, wherein in step S5, the vacuum heating treatment is performed at a temperature of 350 to 400 ℃ for 0.5 to 3 hours at a vacuum degree of 5 to 10 pa.
9. 9. The preparation method according to claim 4, comprising at least one of the following technical features: a4, rotating speeds of the first time and the fourth time in the ball milling treatment are 100-200 rpm, and the ball milling time is 2-72 hours; And B4, rotating speeds of the second time and the third time in the ball milling treatment are 200-600 revolutions per minute, and the ball milling time is 0.3-5 hours.
10. 10. The method according to claim 4, wherein the second ball milling time is 0.3 to 0.5 hours.

Description

Intra-crystal dispersion strengthening type aluminum magnesium alloy and preparation method thereof Technical Field The invention relates to the technical field of preparation of metals and composite materials thereof, in particular to an intra-crystal dispersion strengthening type aluminum magnesium alloy and a preparation method thereof. Background The aluminum-magnesium alloy and the composite material thereof have remarkable structure light weight advantages, are applied to the fields of ships, new energy automobiles, intelligent wear and the like, but have lower yield strength and Young modulus, and limit the application scene. The introduction of a ceramic particle reinforced phase to prepare a dispersion strengthening aluminum magnesium matrix composite is considered as one of important means for improving the strength and modulus at room temperature/high temperature. However, high-content ceramic particles are generally agglomerated at the grain boundaries of the matrix, so that the matrix grains are obviously thinned to submicron size, the alloy is extremely easy to crack along the grains in the stretching and plastic processing processes, the plasticity and formability are obviously reduced, and the modulus is also limited due to uneven distribution of the particles. How to break the strength-plasticity inversion of the dispersion strengthening aluminum magnesium alloy is a key problem to be solved in the urgent need of scientific research and engineering application. Currently, the main means for improving plasticity is to actively and orderly construct a matrix mixed crystal structure, such as a bimodal grain heterostructure in which submicron fine crystals and micron coarse crystals coexist. The method utilizes submicron fine crystals to provide reinforcement, and utilizes micron coarse crystals to improve the work hardening and plastic deformation capacity. However, the introduction of coarse grains tends to reduce yield strength compared to sub-micron fine grain alloys, and still fails to break through the strength-plastic inversion bottleneck. In addition, high-content grain boundary ceramic particles still can cause along-grain cracking, so that the early debonding of a fine grain/coarse grain interface is induced, the coarse grain plasticizing effect cannot be fully exerted, and meanwhile, agglomerated grain boundary particles cannot effectively improve the boosting modulus. Therefore, how to further improve the strength and reduce the plastic loss induced by grain boundary ceramic particles based on a bimodal grain structure is the core direction of the current dispersion strengthening type aluminum magnesium alloy tissue design and process optimization. As reported in the documents "int. J. Plast.194 (2025) 104485" and "J. Mater. Sci. Technol.209 (2025) 117", the incorporation of grain boundary ceramic particles into crystals in large amounts can simultaneously improve the strength and plasticity of bimodal materials. This is because the intra-crystalline ceramic particles not only excite the Orowan strengthening mechanism, but also induce back stress hardening during alloy deformation, relieve the concentration of grain boundary stress, and resist edge grain cracking and fine grain/coarse grain interface debonding. Therefore, if the high-content ceramic particle crystal internalization technology based on an aluminum-magnesium composite system can be developed, the high-strength, high-modulus and high-plastic dispersion strengthening aluminum-magnesium alloy is expected to be prepared. It is worth noting that the chinese patent application of publication No. CN117965973a provides a high-strength and high-toughness aluminum-magnesium alloy composite material and a preparation method thereof, which can be made into a "dispersion+precipitation" coupling reinforced composite material with "low-content ceramic particles+g.p. region" in the crystal, and has excellent strength and plasticity. However, the modulus cannot be improved in the g.p. region, and the modulus-increasing effect is limited due to insufficient content of ceramic particles, so that the application requirements cannot be met. Although ceramic particles have the mode increasing and strengthening effects at the same time, the problem that the plasticizing mode increasing effect is limited due to the fact that high-content ceramic particles are introduced into crystals, high-efficiency in-crystal dispersion distribution of the particles is difficult to achieve and the particles are easy to agglomerate in crystal boundaries in the prior art. Existing ceramic grain crystallization techniques either rely on grain boundary migration and ceramic grain de-pinning during hot working (chinese patent application publication No. CN118497541 a), or require surface treatment of the nano-ceramic particles (nat. Mater.23 (2024) 747). The former has a low crystal internalization ratio, the proportion of ceramic particles entering the crystal