Preparation method of aluminum alloy with efficiently refined grains
阅读说明：本技术 一种晶粒高效细化的铝合金制备方法 (Preparation method of aluminum alloy with efficiently refined grains ) 是由 张丽丽 赵九洲 何杰 江鸿翔 于 2020-11-30 设计创作，主要内容包括：本发明涉及一种晶粒高效细化的铝合金制备方法,属于铝合金制备技术领域。该方法包含如下步骤：(1)将工业纯铝加热、熔化,于650～750℃保温,形成熔体A；(2)用与步骤(1)相同的工业纯铝稀释晶粒细化剂Al-Ti-B中间合金,并加热、熔化,于800～1200℃保温、搅拌至Al-5Ti-1B中间合金中的TiB-2、TiAl-3粒子完全溶解,形成熔体B；(3)将熔体B快冷至熔体A的保温温度后,恒温静置0～30min,期间不断搅拌；(4)将熔体B快速倒入熔体A中、充分搅拌形成熔体C后,浇入模具内冷却,即可获得晶粒高效细化的铝合金铸锭。本发明通过将Al-Ti-B中间合金于高温重熔、保温一定时间,形成均一熔体后,直接降温、细化铝合金。本发明制备方法提高铝合金晶粒细化程度,具有很好的工业应用前景。(The invention relates to a preparation method of an aluminum alloy with efficiently refined grains, belonging to the technical field of aluminum alloy preparation. The method comprises the following steps: (1) heating and melting industrial pure aluminum, and preserving heat at 650-750 ℃ to form a melt A; (2) diluting the grain refiner Al-Ti-B intermediate alloy with the same industrial pure aluminum as the step (1), heating, melting, preserving heat at 800-1200 ℃, and stirring to TiB in the Al-5Ti-1B intermediate alloy 2 、TiAl 3 The particles are completely dissolved to form a melt B; (3) quickly cooling the melt B to the heat preservation temperature of the melt A, standing at the constant temperature for 0-30 min, and continuously stirring during the standing; (4) and quickly pouring the melt B into the melt A, fully stirring to form a melt C, pouring into a mold, and cooling to obtain the aluminum alloy ingot with efficiently refined grains. The Al-Ti-B intermediate alloy is remelted at high temperature and is kept at a certain temperatureAnd (3) after forming uniform melt, directly cooling and refining the aluminum alloy. The preparation method provided by the invention improves the grain refinement degree of the aluminum alloy, and has a good industrial application prospect.)
1. The preparation method of the aluminum alloy with the efficiently refined grains is characterized by comprising the following steps:
(1) heating and melting industrial pure aluminum, and preserving heat at 650-750 ℃ to form a melt A;
(2) diluting the grain refiner Al-Ti-B intermediate alloy with the same industrial pure aluminum as the step (1), heating, melting, preserving heat at 800-1200 ℃, and stirring to TiB in the Al-5Ti-1B intermediate alloy2、TiAl3The particles are completely dissolved to form a melt B;
(3) quickly cooling the melt B to the heat preservation temperature of the melt A, standing at the constant temperature for 0-30 min, and continuously stirring during the standing;
(4) and quickly pouring the melt B into the melt A, fully stirring to form a melt C, pouring into a mold, and cooling to obtain the aluminum alloy ingot with efficiently refined grains.
2. The method for preparing the aluminum alloy with the efficiently refined crystal grains according to claim 1, wherein the grain size of the industrial pure aluminum is 1-15 cm, and the grain size of the Al-Ti-B intermediate alloy is 0.2-10 cm.
3. The method for preparing the aluminum alloy with the efficiently refined crystal grains according to claim 1, wherein the melt B obtained in the step (2) contains Al-5Ti-1B which accounts for 0.2-9.0% of the mass of the industrial pure aluminum.
4. The method for preparing the aluminum alloy with the efficiently refined crystal grains according to claim 1, characterized in that in the step (3), the rapid cooling speed is 10-1000 ℃/s, and the aluminum alloy is kept standing for 10-30 min at a constant temperature.
5. The method for preparing the aluminum alloy with the efficiently refined crystal grains according to claim 1, wherein in the aluminum alloy ingot obtained in the step (4), the mass percentages of Ti and B are respectively as follows: 0.003-0.05% and 0.0006-0.01%.
6. The preparation method of the aluminum alloy with the efficiently refined crystal grains according to claim 1, characterized in that the aluminum alloy ingot obtained in the step (4) contains Al-5Ti-1B in an amount of 0.2-0.6% by mass of the industrial pure aluminum.
7. The method for preparing the aluminum alloy with efficiently refined crystal grains according to claim 1, wherein the size of the crystal grains in the aluminum alloy ingot obtained in the step (4) is 50-150 micrometers.
Technical Field
The invention relates to a preparation method of an aluminum alloy with efficiently refined grains, belonging to the technical field of aluminum alloy preparation.
Background
In industrial production, Al-Ti-B intermediate alloy is commonly used for refining the as-cast grain structure of aluminum alloy. Researches on the influence of Al-Ti-B on an alpha-Al grain refining mechanism and an aluminum alloy solidification structure are very intensive and make remarkable progress. Research shows that solute Ti and TiB with proper size and concentrated distribution exist in the aluminum alloy melt2When in particle, the grain refining effect is better. However, TiB in Al-5Ti-1B master alloy2The particle size distribution is broad, there are usually some TiB with sizes above a few microns2TiB of larger particle and size2The grain cluster is formed, the refining treatment is carried out on the aluminum alloy melt by using the refiner according to the traditional refining process, and serious harm can be brought to the subsequent processing of some aluminum alloy ingots, such as: resulting in pinholes in the aluminum foil or surface scratches, streaks, etc. in the aluminum alloy sheet structure for aviation. In addition, the grain refining effect cannot meet the production requirement of high-performance aluminum alloy. Therefore, the research and development of a novel efficient refining treatment method can improve the grain refining effect, and has important scientific and practical significance.
Disclosure of Invention
The invention aims to provide a preparation method of an aluminum alloy with efficiently refined grains, so as to meet the requirement of the aluminum alloy industry on high-quality aluminum alloy products in industrial production.
In order to achieve the purpose, the invention adopts the technical scheme that:
a preparation method of an aluminum alloy with efficiently refined grains comprises the following steps:
(1) heating and melting industrial pure aluminum, and preserving heat at 650-750 ℃ to form a melt A;
(2) diluting the grain refiner Al-Ti-B intermediate alloy with the same industrial pure aluminum as the step (1), heating, melting, preserving heat at 800-1200 ℃, and stirring to TiB in the Al-5Ti-1B intermediate alloy2、TiAl3The particles are completely dissolved to form a melt B;
(3) quickly cooling the melt B to the heat preservation temperature of the melt A, standing at the constant temperature for 0-30 min, and continuously stirring during the standing;
(4) and quickly pouring the melt B into the melt A, fully stirring to form a melt C, pouring into a mold, and cooling to obtain the aluminum alloy ingot with efficiently refined grains.
The preparation method of the aluminum alloy with the efficiently refined crystal grains has the advantages that the granularity of the industrial pure aluminum is 1-15 cm, and the granularity of the Al-Ti-B intermediate alloy is 0.2-10 cm.
According to the preparation method of the aluminum alloy with the efficiently refined crystal grains, the melt B containing Al-5Ti-1B accounting for 0.2-9.0% of the mass of the industrial pure aluminum is formed in the melt B obtained in the step (2).
In the preparation method of the aluminum alloy with the efficiently refined crystal grains, in the step (3), the preferable fast cooling speed is 10-1000 ℃/s, and the aluminum alloy is kept stand at a constant temperature for 10-30 min.
In the preparation method of the aluminum alloy with efficiently refined crystal grains, in the aluminum alloy ingot obtained in the step (4), Ti and B account for the following mass percent respectively: 0.003-0.05% and 0.0006-0.01%.
According to the preparation method of the aluminum alloy with the efficiently refined crystal grains, the mass percent of Al-5Ti-1B in the aluminum alloy ingot obtained in the step (4) is 0.2-0.6%.
According to the preparation method of the aluminum alloy with the efficiently refined crystal grains, the size of the crystal grains in the aluminum alloy ingot obtained in the step (4) is 50-150 micrometers.
The preparation method has the advantages and beneficial effects that:
the aluminum alloy ingot prepared by the preparation method has the advantages of high equiaxial degree of grain structure, small average grain size and concentrated size distribution range.
Drawings
FIG. 1 shows the grain structure of commercially pure aluminum containing Al-5Ti-1B in an amount of 0.4% by mass based on the mass of the commercially pure aluminum, obtained by the preparation method described in example 1.
FIG. 2 is a graph showing the average grain size of commercially pure aluminum containing Al-5Ti-1B in an amount of 0.4% by mass based on the mass of the commercially pure aluminum obtained by the preparation method described in example 1.
FIG. 3 shows that the traditional refining method is to add Al-5Ti-1B master alloy accounting for 0.4 percent of the mass of the industrial pure aluminum into the industrial pure aluminum melt at 680 ℃, stir and preserve heat for 5min and then pour the obtained industrial pure aluminum grain structure.
FIG. 4 shows the average grain size of the industrial pure aluminum obtained by adding Al-5Ti-1B master alloy accounting for 0.4 percent of the mass of the industrial pure aluminum into an industrial pure aluminum melt at 680 ℃, stirring, preserving the heat for 5min and post-casting according to the traditional refining method.
Detailed Description
In the invention, the Al-5Ti-1B intermediate alloy is prepared by adopting a fluorine salt reaction method, which is disclosed in Chinese patent publication No.: CN107034374A, the method comprises the following steps: carrying out chemical reaction on a fluorine salt mixture and an aluminum melt to obtain an Al-5Ti-1B intermediate alloy; wherein: according to the mass percentage of each component in the fluorine salt mixture in the aluminum melt, the fluorine salt mixture comprises the following components: k2TiF622 to 30% of KBF410-14% of CaF20.01 to 0.114% of MgF20.01 to 0.114% and 2 to 8% of a fluorine salt residue produced by a fluorine salt reaction method. Melting pure aluminum by adopting a medium-frequency induction furnace to obtain an aluminum melt, heating to 750-850 ℃, completely covering a fluorine salt mixture on the surface of the aluminum melt, carrying out heat preservation reaction for 30-60 min at the temperature of 750-850 ℃ to obtain an Al-5Ti-1B intermediate alloy melt and fluorine salt residues on the surface of the Al-5Ti-1B intermediate alloy melt, and pouring out the fluorine salt residues on the surface of the Al-5Ti-1B intermediate alloy melt to obtain the Al-5Ti-1B intermediate alloy.
The invention is described in detail below with reference to the accompanying drawings and examples.
Example 1
In this embodiment, the preparation method of the aluminum alloy with efficiently refined grains is as follows:
(1) heating and melting industrial pure aluminum with the average particle size of 3cm, and preserving heat at 680 ℃ to form a melt A;
(2) diluting a grain refiner Al-5Ti-1B intermediate alloy with the average grain size of 0.5cm by using the same industrial pure aluminum as the step (1), heating, melting, preserving the temperature at 950 ℃, and stirring until TiB in the Al-5Ti-1B intermediate alloy2、TiAl3The particles are completely dissolved to form a melt B containing Al-5Ti-1B accounting for 0.8 percent of the mass of the industrial pure aluminum;
(3) cooling the melt B to 680 ℃ at a speed of 50 ℃/s, standing for 15min at a constant temperature, and continuously stirring;
(4) and quickly pouring the melt B into the melt A, fully stirring to form a melt C, fully stirring, pouring into a stainless steel mold, and cooling to obtain the aluminum alloy cast ingot containing Al-5Ti-1B accounting for 0.4% of the mass of the industrial pure aluminum. In the obtained aluminum alloy ingot, Ti and B respectively account for the following mass percent: 0.02% and 0.004%.
The obtained aluminum alloy cast ingot is cut along the radial direction at the position 20mm away from the bottom surface, and is subjected to electrolytic polishing and corrosion by using an ethanol solution containing perchloric acid with the volume fraction of 5 percent after grinding and polishing.
As shown in fig. 1, the microstructure of the ingot is observed by an optical microscope, and it can be seen from the figure that the industrial pure aluminum ingot prepared by the preparation method of the invention has fine grain structure and high equiaxial degree; the size distribution range is more concentrated.
As shown in fig. 2, the grain size of the commercial pure aluminum was measured by quantitative metallographic analysis software, and it can be seen from the figure that the average grain size of the commercial pure aluminum ingot obtained by the preparation method of the present invention was small. Compared with the conventional refining method (fig. 3 and 4), the grain refining effect is greatly improved.
The embodiment result shows that the Al-Ti-B intermediate alloy is remelted at high temperature and kept for a certain time to form a uniform melt, and then the temperature is directly reduced and the aluminum alloy is refined. The preparation method provided by the invention improves the grain refinement degree of the aluminum alloy, and has a good industrial application prospect.
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