阅读说明：本技术 一种控制Al-Mg-Si-Mn合金中弥散粒子尺寸的热处理方法 (Heat treatment method for controlling size of dispersed particles in Al-Mg-Si-Mn alloy ) 是由 邱楚 郭世杰 于 2020-07-30 设计创作，主要内容包括：本发明的一种控制Al-Mg-Si-Mn合金中弥散粒子尺寸的热处理方法,包括以下步骤：(1)将Al-Mg-Si-Mn合金熔炼、铸造,得到Al-Mg-Si-Mn合金铸锭；铸造过程中Al-Mg-Si-Mn合金的冷却速率为9K/s～50K/s；(2)将Al-Mg-Si-Mn合金铸锭升温至150℃～300℃保温1h～10h、再升温至350℃～530℃保温2h～12h、最后升温至540℃～590℃保温4h～20h后冷却至室温,得到控制弥散粒子尺寸后的Al-Mg-Si-Mn合金；本发明方法制得的合金组织中AlMn(Cr)Si粒子尺寸的平均值为50～200nm、最大值为70～600nm。(The invention relates to a heat treatment method for controlling the size of dispersed particles in an Al-Mg-Si-Mn alloy, which comprises the following steps: (1) smelting and casting the Al-Mg-Si-Mn alloy to obtain an Al-Mg-Si-Mn alloy ingot; the cooling rate of the Al-Mg-Si-Mn alloy in the casting process is 9K/s-50K/s; (2) heating the Al-Mg-Si-Mn alloy ingot to 150-300 ℃, preserving heat for 1-10 h, heating to 350-530 ℃, preserving heat for 2-12 h, finally heating to 540-590 ℃, preserving heat for 4-20 h, and cooling to room temperature to obtain the Al-Mg-Si-Mn alloy with the dispersed particle size controlled; the average value of the sizes of AlMn (Cr) Si particles in the alloy structure prepared by the method is 50-200 nm, and the maximum value is 70-600 nm.)

1. A heat treatment method for controlling the size of dispersed particles in an Al-Mg-Si-Mn alloy is characterized in that the Al-Mg-Si-Mn alloy comprises the following components in percentage by mass: 0.4 to 1.2 percent of Mg, 0.3 to 1.2 percent of Si, 0.1 to 2.0 percent of Mn, 0.1 to 0.6 percent of Cr, 0.1 to 0.7 percent of Fe, 0.1 to 0.6 percent of Cu, 0.2 percent of Ti, 0.2 percent of Zn and the balance of Al; the method comprises the following steps:

(1) smelting and casting the Al-Mg-Si-Mn alloy to obtain an Al-Mg-Si-Mn alloy ingot; the cooling rate of the Al-Mg-Si-Mn alloy in the casting process is 9K/s-50K/s;

(2) carrying out primary heat treatment on the Al-Mg-Si-Mn alloy cast ingot to obtain an Al-Mg-Si-Mn alloy cast ingot subjected to the primary heat treatment; the process conditions of the first-stage heat treatment are as follows: the temperature of the first-stage heat treatment is 150-300 ℃, the heat preservation time of the first-stage heat treatment is 1-10 h, and the heating rate of the Al-Mg-Si-Mn alloy ingot from the room temperature to the temperature of the first-stage heat treatment is 20-200 ℃/h;

(3) carrying out secondary heat treatment on the Al-Mg-Si-Mn alloy cast ingot subjected to the primary heat treatment to obtain an Al-Mg-Si-Mn alloy cast ingot subjected to the secondary heat treatment; the process conditions of the second-stage heat treatment are as follows: the temperature of the second-stage heat treatment is 350-530 ℃, the heat preservation time of the second-stage heat treatment is 2-12 h, and the heating rate of the Al-Mg-Si-Mn alloy ingot after the first-stage heat treatment from the temperature of the first-stage heat treatment to the temperature of the second-stage heat treatment is 300-600 ℃/h;

(4) carrying out third-stage heat treatment on the Al-Mg-Si-Mn alloy cast ingot subjected to the second-stage heat treatment, and cooling to room temperature to obtain an Al-Mg-Si-Mn alloy with dispersed particle size controlled; the process conditions of the third-stage heat treatment are as follows: the temperature of the third-stage heat treatment is 540-590 ℃, the heat preservation time of the third-stage heat treatment is 4-20 h, and the heating rate of the Al-Mg-Si-Mn alloy ingot after the second-stage heat treatment from the second-stage heat treatment temperature to the third-stage heat treatment temperature is 5-50 ℃/h.

2. The heat treatment method for controlling the dispersed particle size in the Al-Mg-Si-Mn alloy according to claim 1, wherein the sum of the holding time of the first-stage heat treatment in the step (2), the holding time of the second-stage heat treatment in the step (3), and the holding time of the third-stage heat treatment in the step (4) is 10 to 50 hours.

3. A heat treatment method for controlling dispersed particle size in Al-Mg-Si-Mn alloy according to claim 1, wherein the Al-Mg-Si-Mn alloy is one of 6-series aluminum alloys containing Mn element.

4. A heat treatment method for controlling dispersed particle size in Al-Mg-Si-Mn alloy according to claim 3, wherein the Al-Mg-Si-Mn alloy is one of 6005A aluminum alloy, 6061 aluminum alloy, 6082 aluminum alloy, and 6351 aluminum alloy.

5. The heat treatment method for controlling the dispersed particle size in the Al-Mg-Si-Mn alloy according to claim 1, wherein the cooling manner of cooling the Al-Mg-Si-Mn alloy ingot subjected to the second-stage heat treatment to room temperature in the step (4) after the third-stage heat treatment is one or more of water mist cooling, air cooling and air cooling.

6. The heat treatment method for controlling the dispersed particle size in the Al-Mg-Si-Mn alloy according to claim 1, wherein the dispersed particles in the Al-Mg-Si-Mn alloy obtained in the step (4) after controlling the dispersed particle size have an average size of 50nm to 200nm and a maximum size of 70nm to 600 nm.

Technical Field

The invention relates to the field of non-ferrous metal material engineering, in particular to a heat treatment method for controlling the size of dispersed particles in an Al-Mg-Si-Mn alloy.

Background

The aluminum alloy has the characteristics of low density, high specific strength, good corrosion resistance, excellent plasticity and the like, and is widely applied to the fields of aerospace, transportation, machinery, electronics, buildings and the like. The Al-Mg-Si alloy belongs to the category of 6 series aluminum alloys, is a typical representative of medium-high strength aluminum alloys, is widely applied to the fields of automation, aerospace, rail transit and the like, and develops a novel Al-Mg-Si-Mn alloy for further improving the strength, toughness and corrosion resistance of the material, and typical brands are 6005A, 6351, 6082, 6061 and the like. Besides the excellent performance of the traditional Al-Mg-Si alloy, the added proper amount of Mn element can raise the recrystallization temperature and inhibit recrystallization. Al-Mg-Si-Mn alloy can form AlMn (Cr) Si dispersed particles in the heat treatment process, the particles can pin dislocation and grain boundary in the subsequent heat treatment process, and the substructure of the stable deformation structure plays the roles of inhibiting recrystallization and stabilizing the subgrain structure, thereby improving the strength and fatigue property of the alloy. Meanwhile, AlMn (Cr) Si particles are easy to coarsen in the heat treatment process, the average pinning force of the AlMn (Cr) Si particles to grain boundaries and dislocation is reduced, and the effect of inhibiting recrystallization is greatly weakened.

At present, most of research on precipitation of dispersed phases mainly focuses on heat treatment control methods of Al-Zn-Mg-Cu and Al-Cu alloys, while most of research on heat treatment processes of Al-Mg-Si-Mn alloys focuses on how to regulate and control distribution of strengthening precipitated phases and grain boundary precipitated phases, and few researches on how to regulate and control precipitation sizes of AlMn (Cr) Si particles and fully exert recrystallization inhibition effects of the AlMn (Cr) Si particles. Because aluminum alloy is based on different chemical composition, the types and sizes of dispersed phases in the structure have obvious difference, and therefore, the research content of controlling the precipitation size of AlMn (Cr) Si dispersed particles in the Al-Mg-Si-Mn alloy is very significant in technology.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides a method for obtaining a structure which has small AlMn (Cr) Si particle size and is uniformly and dispersedly distributed in a matrix, and the structure obtained by the method is beneficial to realizing the purposes of inhibiting recrystallization and improving the sub-crystalline fraction of the material in the hot working process.

The invention adopts the following technical scheme:

a heat treatment method for controlling the size of dispersed particles in an Al-Mg-Si-Mn alloy is characterized in that the Al-Mg-Si-Mn alloy comprises the following components in percentage by mass: 0.4 to 1.2 percent of Mg, 0.3 to 1.2 percent of Si, 0.1 to 2.0 percent of Mn, 0.1 to 0.6 percent of Cr, 0.1 to 0.7 percent of Fe, 0.1 to 0.6 percent of Cu, 0.2 percent of Ti, 0.2 percent of Zn and the balance of Al; the method comprises the following steps:

(1) smelting and casting the Al-Mg-Si-Mn alloy to obtain an Al-Mg-Si-Mn alloy ingot; the cooling rate of the Al-Mg-Si-Mn alloy in the casting process is 9K/s-50K/s;

(2) carrying out primary heat treatment on the Al-Mg-Si-Mn alloy cast ingot to obtain an Al-Mg-Si-Mn alloy cast ingot subjected to the primary heat treatment; the process conditions of the first-stage heat treatment are as follows: the temperature of the first-stage heat treatment is 150-300 ℃, the heat preservation time of the first-stage heat treatment is 1-10 h, and the heating rate of the Al-Mg-Si-Mn alloy ingot from the room temperature to the temperature of the first-stage heat treatment is 20-200 ℃/h;

(3) carrying out secondary heat treatment on the Al-Mg-Si-Mn alloy cast ingot subjected to the primary heat treatment to obtain an Al-Mg-Si-Mn alloy cast ingot subjected to the secondary heat treatment; the process conditions of the second-stage heat treatment are as follows: the temperature of the second-stage heat treatment is 350-530 ℃, the heat preservation time of the second-stage heat treatment is 2-12 h, and the heating rate of the Al-Mg-Si-Mn alloy ingot after the first-stage heat treatment from the temperature of the first-stage heat treatment to the temperature of the second-stage heat treatment is 300-600 ℃/h;

(4) carrying out third-stage heat treatment on the Al-Mg-Si-Mn alloy cast ingot subjected to the second-stage heat treatment, and cooling to room temperature to obtain an Al-Mg-Si-Mn alloy with dispersed particle size controlled; the process conditions of the third-stage heat treatment are as follows: the temperature of the third-stage heat treatment is 540-590 ℃, the heat preservation time of the third-stage heat treatment is 4-20 h, and the heating rate of the Al-Mg-Si-Mn alloy ingot after the second-stage heat treatment from the second-stage heat treatment temperature to the third-stage heat treatment temperature is 5-50 ℃/h.

The heat treatment method for controlling the size of dispersed particles in the Al-Mg-Si-Mn alloy is characterized in that the sum of the heat preservation time of the first-stage heat treatment in the step (2), the heat preservation time of the second-stage heat treatment in the step (3) and the heat preservation time of the third-stage heat treatment in the step (4) is 10-50 hours.

The heat treatment method for controlling the size of dispersed particles in the Al-Mg-Si-Mn alloy is characterized in that the Al-Mg-Si-Mn alloy is one of 6 series aluminum alloys containing Mn.

The heat treatment method for controlling the size of dispersed particles in the Al-Mg-Si-Mn alloy is characterized in that the Al-Mg-Si-Mn alloy is one of 6005A aluminum alloy, 6061 aluminum alloy, 6082 aluminum alloy and 6351 aluminum alloy.

The heat treatment method for controlling the size of dispersed particles in the Al-Mg-Si-Mn alloy is characterized in that in the step (4), the cooling mode of cooling the Al-Mg-Si-Mn alloy ingot subjected to the second-stage heat treatment to room temperature after the third-stage heat treatment is one or more of water mist cooling, air cooling and air cooling.

The heat treatment method for controlling the size of the dispersed particles in the Al-Mg-Si-Mn alloy is characterized in that the average size of the dispersed particles in the Al-Mg-Si-Mn alloy after controlling the size of the dispersed particles obtained in the step (4) is 50 nm-200 nm, and the maximum size of the dispersed particles is 70 nm-600 nm.

Compared with the prior art, the invention has the beneficial technical effects that: the invention aims to regulate and control the precipitation size of AlMn (Cr) Si dispersion particles in a matrix through homogenization heat treatment, and finally obtain a structure which is fine in AlMn (Cr) Si particle size, uniform in the matrix and distributed in a dispersion manner, wherein the structure is favorable for realizing the purposes of inhibiting recrystallization and improving the subgrain fraction of the material in the hot working process. In order to control the size of AlMn (Cr) Si dispersed particles in the Al-Mg-Si-Mn alloy, firstly, a large amount of Mn element is dissolved in a matrix by controlling the cooling rate in the casting process, and the generation of coarse Mn-containing phases among grains is reduced; after the ingot is formed, a third stage heat treatment is carried out, namely the first stage heat treatmentThe treatment is a heat treatment at a lower temperature to promote the precipitation of dispersed and fine beta' -Mg in the tissue₂The purpose of Si phase is to continuously heat up and disperse finely distributed beta' -Mg₂The Si phase is converted into nucleation cores of AlMn (Cr) Si particles; the second stage of heat treatment is higher temperature heat treatment to promote the homogenization of alloy elements in the structure crystal grains, the full diffusion of Mn element and the full nucleation and growth of AlMn (Cr) Si particles in the structure; and finally, eliminating the undissolved coarse phase of the ingot by adopting a third-stage homogenization heat treatment, and meanwhile, discontinuously and spheroidizing the high-melting-point phase. The method is characterized in that Mn element is controlled to form and precipitate a large amount of AlMn (Cr) Si dispersion particles in the internal structure of ingot casting grains, the optimal structure with the average value of the sizes of the AlMn (Cr) Si dispersion particles of 50-200 nm and the maximum size of 70-600 nm is obtained, and the percentage of subgrain in the final structure of the alloy is improved by 15% -30%; the AlMn (Cr) Si dispersion particles in the cast ingot in the subsequent hot working process can fully play a role in inhibiting recrystallization, thereby improving the comprehensive mechanical property and fatigue property of the material. The heat treatment method disclosed by the invention is wide in application, has good operability under industrial conditions, requires energy consumption equivalent to that of the traditional method, and fully considers the industrial applicability of the Al-Mg-Si-Mn alloy.

Drawings

FIG. 1 is a TEM image of dispersed particles of AlMn (Cr) Si in the aluminum alloy of example 1 of the present invention;

FIG. 2 is a TEM image of dispersed particles of AlMn (Cr) Si in the aluminum alloy of example 2 of the present invention;

FIG. 3 is a TEM image of dispersed particles of AlMn (Cr) Si in the aluminum alloy of example 3 of the present invention;

FIG. 4 is a TEM image of dispersed particles of AlMn (Cr) Si in the aluminum alloy of example 4 of the present invention;

FIG. 5 is a TEM image of dispersed particles of AlMn (Cr) Si in the aluminum alloy of example 5 of the present invention;

FIG. 6 is a TEM image of dispersed particles of AlMn (Cr) Si in the aluminum alloy of comparative example 1 according to the present invention;

FIG. 7 is a TEM image of dispersed particles of AlMn (Cr) Si in an aluminum alloy of comparative example 2 according to the present invention;

FIG. 8 is a TEM image of dispersed particles of AlMn (Cr) Si in an aluminum alloy of comparative example 3 according to the present invention;

FIG. 9 is a metallographic structure coating diagram showing the recrystallization control effect of the aluminum alloy according to example 1 of the present invention;

FIG. 10 is a metallographic structure coating diagram showing the recrystallization control effect of the aluminum alloy of comparative example 1 according to the present invention.

Detailed Description

The present invention will be further described in detail below with reference to the drawings, specific examples and comparative examples to make the invention easier to understand and understand. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. Based on the embodiments of the invention. All other embodiments obtained by a person skilled in the art without making any inventive step are within the scope of protection of the present invention.

The invention relates to a heat treatment method for controlling the size of dispersed particles in an Al-Mg-Si-Mn alloy, which comprises the following components in percentage by mass: 0.4 to 1.2 percent of Mg, 0.3 to 1.2 percent of Si, 0.1 to 2.0 percent of Mn, 0.1 to 0.6 percent of Cr, 0.1 to 0.7 percent of Fe, 0.1 to 0.6 percent of Cu, 0.2 percent of Ti, 0.2 percent of Zn and the balance of Al; the method comprises the following steps:

(1) smelting and casting the Al-Mg-Si-Mn alloy to obtain an Al-Mg-Si-Mn alloy ingot; the cooling rate of the Al-Mg-Si-Mn alloy in the casting process is 9K/s-50K/s; the Al-Mg-Si-Mn alloy is one of 6 series aluminum alloys containing Mn elements, and preferably, the Al-Mg-Si-Mn alloy is one of 6005A aluminum alloy, 6061 aluminum alloy, 6082 aluminum alloy and 6351 aluminum alloy.

(2) Carrying out primary heat treatment on the Al-Mg-Si-Mn alloy cast ingot to obtain an Al-Mg-Si-Mn alloy cast ingot subjected to the primary heat treatment; the process conditions of the first-stage heat treatment are as follows: the temperature of the first-stage heat treatment is 150-300 ℃, the heat preservation time of the first-stage heat treatment is 1-10 h, and the heating rate of the Al-Mg-Si-Mn alloy ingot from the room temperature to the temperature of the first-stage heat treatment is 20-200 ℃/h;

(3) carrying out secondary heat treatment on the Al-Mg-Si-Mn alloy cast ingot subjected to the primary heat treatment to obtain an Al-Mg-Si-Mn alloy cast ingot subjected to the secondary heat treatment; the process conditions of the second-stage heat treatment are as follows: the temperature of the second-stage heat treatment is 350-530 ℃, the heat preservation time of the second-stage heat treatment is 2-12 h, and the heating rate of the Al-Mg-Si-Mn alloy ingot after the first-stage heat treatment from the temperature of the first-stage heat treatment to the temperature of the second-stage heat treatment is 300-600 ℃/h; the sum of the first-stage heat treatment heat preservation time in the step (2), the second-stage heat treatment heat preservation time in the step (3) and the third-stage heat treatment heat preservation time in the step (4) is 10-50 h.

(4) And carrying out third-stage heat treatment on the Al-Mg-Si-Mn alloy cast ingot subjected to the second-stage heat treatment, and cooling to room temperature, wherein the cooling mode is one or combination of water mist cooling, air cooling and air cooling. Cooling to room temperature to obtain Al-Mg-Si-Mn alloy with the dispersion particle size controlled; the average size of the dispersed particles in the Al-Mg-Si-Mn alloy after controlling the size of the dispersed particles is 50 nm-200 nm, and the maximum size is 70 nm-600 nm. The process conditions of the third-stage heat treatment are as follows: the temperature of the third-stage heat treatment is 540-590 ℃, the heat preservation time of the third-stage heat treatment is 4-20 h, and the heating rate of the Al-Mg-Si-Mn alloy ingot after the second-stage heat treatment from the second-stage heat treatment temperature to the third-stage heat treatment temperature is 5-50 ℃/h.