A method for preparing erbium-containing Al-Mg alloy

Abstract

This invention relates to a method for preparing erbium-containing Al-Mg alloys, belonging to the field of aluminum alloy material preparation technology. The invention involves batching materials according to the composition of the erbium-containing Al-Mg alloy, vacuum melting at 740–770℃, and then semi-continuous casting at 720–750℃ to obtain an erbium-containing Al-Mg alloy ingot. The erbium-containing Al-Mg alloy ingot undergoes two-stage homogenization annealing and cooling to room temperature to obtain a homogenized annealed erbium-containing Al-Mg alloy. The homogenized annealed erbium-containing Al-Mg alloy is then uniformly heated to 200–400℃ at a heating rate of 2–10℃ / min for non-isothermal annealing, followed by air cooling to obtain the erbium-containing Al-Mg alloy. This invention, through composite microalloying and non-isothermal heat treatment processes, yields Al-Mg alloys with high strength and excellent elongation. The process is simple and controllable, and the resulting Al-Mg alloy exhibits excellent properties, facilitating large-scale industrial applications.

Description

Technical Field

[0001] This invention relates to a method for preparing an erbium-containing Al-Mg alloy, belonging to the field of aluminum alloy material preparation technology. Background Technology

[0002] Al-Mg alloys are widely used in the manufacture of various products for the aerospace and marine industries due to their moderate strength, low density, excellent corrosion resistance, good weldability, and significant machinability. The strength of Al-Mg alloys primarily derives from solid solution strengthening and work hardening, largely due to the relatively large size of their precipitates, such as β(Al3Mg2) and Al6Mn phases. The addition of trace amounts of Er and Yb to Al-Zr alloys can accelerate precipitation and increase the number density by forming core-shell structured Al3(Er,Zr) and Al3(Yb,Zr) precipitates. Al-Er-Zr and Al-Yb-Zr alloys exhibit high precipitate number densities and strong resistance to recrystallization. The presence of Er is beneficial to the corrosion resistance of Al-Mg alloys, and a higher Er concentration results in a wider passivation range. During heat treatment, secondary Al3Er particles precipitated at grain boundaries effectively inhibit recrystallization and strengthen the alloy by hindering dislocation slip. To improve strain strengthening or work hardening effects, more refined and complex processing routes are required, which are costly and unsuitable for industrial production. Therefore, commercially available Al-Mg alloys typically only possess medium strength. With the development of aerospace technology and the defense industry, further improving the mechanical properties of existing Al-Mg alloys has become an urgent problem to be solved. Summary of the Invention

[0003] To address the existing problems in the preparation of high-strength erbium-containing Al-Mg alloys, this invention proposes a method for preparing erbium-containing Al-Mg alloys. This invention obtains Al-Mg alloys with high strength and excellent elongation through composite microalloying and non-isothermal heat treatment processes. The process is simple and controllable, and the resulting Al-Mg alloys have excellent properties, making them suitable for large-scale industrial applications.

[0004] A method for preparing an erbium-containing Al-Mg alloy, the specific steps of which are as follows:

[0005] (1) The ingredients are prepared according to the composition of the erbium-containing Al-Mg alloy, and vacuum melted at a temperature of 740-770℃, and then semi-continuously cast at a temperature of 720-750℃ to obtain the erbium-containing Al-Mg alloy ingot.

[0006] (2) Erbium-containing Al-Mg alloy ingots are subjected to two-stage homogenization annealing and cooled to room temperature to obtain homogenized annealed erbium-containing Al-Mg alloy;

[0007] (3) The homogenized annealed erbium-containing Al-Mg alloy is heated at a constant temperature of 2-10℃ / min to a temperature of 200-400℃ for non-isothermal annealing, and then air-cooled to obtain the erbium-containing Al-Mg alloy.

[0008] The erbium-containing Al-Mg alloy contains 4.5–5.5 wt.% Mg, 0.4–0.8 wt.% Mn, 0.1–0.25 wt.% Zn, 0.1–0.25 wt.% Cr, 0.05–0.15 wt.% Ti, 0.1–0.3 wt.% Zr, 0.1–0.4 wt.% Er, ≤0.2 wt.% Fe, ≤0.2 wt.% Si, with the balance being Al.

[0009] The Al element is added in the form of pure aluminum, and the Mg element is added in the form of pure magnesium; Mn, Cr, Ti, Zr and Er are added in the form of master alloys Al-Mn, Al-Cr, Al-Ti, Al-Zr and Al-Er, respectively.

[0010] The first stage of the two-stage homogenization annealing in step (2) is at a homogenization temperature of 300-350℃ for 6-10 hours; the second stage is at a homogenization temperature of 450-490℃ for 12-18 hours.

[0011] The principle behind the high strength and excellent elongation of erbium-containing Al-Mg alloys is as follows: The addition of Er forms nanoscale Al3Er or Al3(Zr,Er) particles that are coherent or semi-coherent with the matrix. These dispersed Al3Er particles have a strong pinning effect. Through a non-isothermal annealing process with slow heating, the driving force for the precipitation of the strengthening phase increases with rising temperature, leading to more nucleation sites and a decrease in the critical radius, ensuring nucleation stability and creating favorable conditions for more dispersed precipitation in the alloy. This allows for a significant increase in strength and hardness while maintaining the alloy's plasticity.

[0012] The beneficial effects of this invention are:

[0013] This invention obtains Al-Mg alloys with high strength and excellent elongation through composite microalloying and non-isothermal heat treatment processes. The tensile strength is increased by more than 10%, the yield strength by more than 20%, and the elongation by more than 40%. Moreover, the process is simple and controllable, which is convenient for large-scale industrial application. Attached Figure Description

[0014] Figure 1 Stress-strain curves of erbium-containing Al-Mg alloy materials prepared for Example 1;

[0015] Figure 2 Stress-strain curves of erbium-containing Al-Mg alloy materials were prepared for Example 2;

[0016] Figure 3 Stress-strain curves of erbium-containing Al-Mg alloy materials were prepared for Example 3;

[0017] Figure 4 The stress-strain curve of the Al-Mg alloy material in Comparative Example 1 is shown.

[0018] Figure 5 The stress-strain curve of the Al-Mg alloy material in Comparative Example 2 is shown.

[0019] Figure 6 The stress-strain curve of the Al-Mg alloy material in Comparative Example 3 is shown. Detailed Implementation

[0020] The present invention will be further described in detail below with reference to specific embodiments, but the scope of protection of the present invention is not limited to the content described.

[0021] Example 1: A method for preparing an erbium-containing Al-Mg alloy, the specific steps of which are as follows:

[0022] (1) According to the composition of the erbium-containing Al-Mg alloy (see Table 1), the high-purity aluminum ingot, high-purity magnesium ingot, and intermediate alloys Al-Mn, Al-Cr, Al-Ti, Al-Zr and Al-Er are added to the vacuum medium-frequency induction furnace and vacuum melted at a temperature of 750℃. Then, the erbium-containing Al-Mg alloy ingot is obtained by semi-continuous casting at a temperature of 740~750℃.

[0023] Table 1 Composition of Erbium-containing Al-Mg alloys

[0024]

[0025] (2) Erbium-containing Al-Mg alloy ingots were subjected to two-stage homogenization annealing and cooled to room temperature to obtain homogenized annealed erbium-containing Al-Mg alloy; wherein the first stage homogenization temperature of the two-stage homogenization annealing was 320℃ and the time was 8h; the second stage homogenization temperature was 470℃ and the time was 16h.

[0026] (3) The homogenized annealed erbium-containing Al-Mg alloy was heated to 250℃ at a constant heating rate of 3.5℃ / min and then air-cooled to obtain the erbium-containing Al-Mg alloy.

[0027] The stress-strain curve of the erbium-containing Al-Mg alloy material prepared in this embodiment is shown in the figure. Figure 1 The Al-Mg alloy has a tensile strength of 263.2 MPa, a yield strength of 148.02 MPa, and an elongation of 7.38%. The hardness of the erbium-containing Al-Mg alloy material in this embodiment is 85.15 HV0.2, as tested.

[0028] Comparative Example 1: Preparation method of erbium-containing Al-Mg alloy, the specific steps are as follows:

[0029] (1) According to the composition of the erbium-containing Al-Mg alloy (the same as in Example 1), high-purity aluminum ingots, high-purity magnesium ingots, and intermediate alloys Al-Mn, Al-Cr, Al-Ti, Al-Zr and Al-Er are added to a vacuum medium-frequency induction furnace and vacuum melted at 750°C. Then, the erbium-containing Al-Mg alloy ingot is obtained by semi-continuous casting at 740-750°C.

[0030] (2) Erbium-containing Al-Mg alloy ingots were subjected to two-stage homogenization annealing and cooled to room temperature to obtain homogenized annealed erbium-containing Al-Mg alloy; wherein the first stage homogenization temperature of the two-stage homogenization annealing was 320℃ and the time was 8h; the second stage homogenization temperature was 470℃ and the time was 16h.

[0031] (3) The homogenized annealed erbium-containing Al-Mg alloy was rapidly heated to 250℃ and held for 1 hour for isothermal annealing, and then air-cooled to obtain the erbium-containing Al-Mg alloy.

[0032] The stress-strain curves of the Al-Mg alloy material in this comparative example are shown below. Figure 4 The Al-Mg alloy has a tensile strength of 237.85 MPa, a yield strength of 129.42 MPa, an elongation of 4.64%, and a hardness of 78.32 HV0.2.

[0033] Compared with the Al-Mg alloy material in the comparative example, the erbium-containing Al-Mg alloy material prepared in Example 1 showed an increase in tensile strength of 10.65%, yield strength of 14.37%, elongation of 59.05%, and hardness of 8.72%. After homogenization annealing, the as-cast segregation structure was eliminated. During the slow heating stage at 3.5℃ / min, the driving force for the precipitation of strengthening phase increased, and the dispersed Al3Er or Al3(Er,Zr) particles had a strong pinning effect, which improved the strength and hardness of the alloy. Since the alloy was slowly heated and not exposed to the thermal environment for a long time (the heating stage was only 64 minutes), the particle pinning effect prevented grain growth and improved elongation.

[0034] Example 2: A method for preparing an erbium-containing Al-Mg alloy, the specific steps of which are as follows:

[0035] (1) According to the composition of the erbium-containing Al-Mg alloy (see Table 2), the high-purity aluminum ingot, high-purity magnesium ingot, and intermediate alloys Al-Mn, Al-Cr, Al-Ti, Al-Zr and Al-Er are added to the vacuum medium-frequency induction furnace and vacuum melted at a temperature of 760℃. Then, the erbium-containing Al-Mg alloy ingot is obtained by semi-continuous casting at a temperature of 750~760℃.

[0036] Table 2 Composition of Erbium-containing Al-Mg alloys

[0037]

[0038] (2) Erbium-containing Al-Mg alloy ingots are subjected to two-stage homogenization annealing and cooled to room temperature to obtain homogenized annealed erbium-containing Al-Mg alloy; wherein the first stage homogenization temperature of the two-stage homogenization annealing is 300℃ and the time is 10h; the second stage homogenization temperature is 450℃ and the time is 12h.

[0039] (3) The homogenized annealed erbium-containing Al-Mg alloy was heated to 300℃ at a constant heating rate of 4.5℃ / min for non-isothermal annealing and then air-cooled to obtain the erbium-containing Al-Mg alloy.

[0040] The stress-strain curve of the erbium-containing Al-Mg alloy material prepared in this embodiment is shown in the figure. Figure 2 The Al-Mg alloy has a tensile strength of 284.83 MPa, a yield strength of 163.43 MPa, and an elongation of 6.6%. The hardness of the erbium-containing Al-Mg alloy material in this embodiment is 91.1 HV0.2, as tested.

[0041] Comparative Example 2: Preparation method of erbium-containing Al-Mg alloy, the specific steps are as follows:

[0042] (1) According to the composition of the erbium-containing Al-Mg alloy (the same as in Example 2), high-purity aluminum ingots, high-purity magnesium ingots, and intermediate alloys Al-Mn, Al-Cr, Al-Ti, Al-Zr and Al-Er are added to a vacuum medium-frequency induction furnace and vacuum melted at 760°C. Then, the erbium-containing Al-Mg alloy ingot is obtained by semi-continuous casting at 750-760°C.

[0043] (2) Erbium-containing Al-Mg alloy ingots are subjected to two-stage homogenization annealing and cooled to room temperature to obtain homogenized annealed erbium-containing Al-Mg alloy; wherein the first stage homogenization temperature of the two-stage homogenization annealing is 300℃ and the time is 10h; the second stage homogenization temperature is 450℃ and the time is 12h.

[0044] (3) The homogenized annealed erbium-containing Al-Mg alloy was rapidly heated to 300℃ and held for 1 hour for isothermal annealing, and then air-cooled to obtain the erbium-containing Al-Mg alloy.

[0045] The stress-strain curves of the Al-Mg alloy material in this comparative example are shown below. Figure 5 The Al-Mg alloy has a tensile strength of 226.96 MPa, a yield strength of 130.9 MPa, an elongation of 4.65%, and a hardness of 76.23 HV0.2.

[0046] Compared with the Al-Mg alloy material in the comparative example, the erbium-containing Al-Mg alloy material prepared in Example 2 showed an increase of 25.5% in tensile strength, 24.85% in yield strength, 41.94% in elongation, and 19.5% in hardness. After homogenization annealing, the as-cast segregation structure was eliminated. During the slow heating stage at 4.5℃ / min, the driving force for the precipitation of strengthening phase increased, and the dispersed Al3Er or Al3(Er,Zr) particles had a strong pinning effect, which improved the strength and hardness of the alloy. Since the alloy was slowly heated and not exposed to the thermal environment for a long time (the heating stage was only 61 minutes), the particle pinning effect prevented grain growth.

[0047] Example 3: A method for preparing an erbium-containing Al-Mg alloy, the specific steps of which are as follows:

[0048] (1) According to the composition of the erbium-containing Al-Mg alloy (see Table 3), the high-purity aluminum ingot, high-purity magnesium ingot, and intermediate alloys Al-Mn, Al-Cr, Al-Ti, Al-Zr and Al-Er are added to the vacuum medium-frequency induction furnace and vacuum melted at a temperature of 740℃. Then, the erbium-containing Al-Mg alloy ingot is obtained by semi-continuous casting at a temperature of 720~740℃.

[0049] Table 3 Composition of Erbium-containing Al-Mg alloys

[0050] (2) Erbium-containing Al-Mg alloy ingots are subjected to two-stage homogenization annealing and cooled to room temperature to obtain homogenized annealed erbium-containing Al-Mg alloy; wherein the first stage homogenization temperature of the two-stage homogenization annealing is 350℃ and the time is 6h; the second stage homogenization temperature is 490℃ and the time is 14h.

[0051] (3) The homogenized annealed erbium-containing Al-Mg alloy was heated to 350℃ at a constant heating rate of 6℃ / min for non-isothermal annealing, and then air-cooled to obtain the erbium-containing Al-Mg alloy.

[0052] The stress-strain curve of the erbium-containing Al-Mg alloy material prepared in this embodiment is shown in the figure. Figure 3The Al-Mg alloy has a tensile strength of 276.35 MPa, a yield strength of 152.56 MPa, and an elongation of 6.88%. The hardness of the erbium-containing Al-Mg alloy material in this embodiment is 87.5 HV0.2, as tested.

[0053] Comparative Example 3: Preparation method of erbium-containing Al-Mg alloy, the specific steps are as follows:

[0054] (1) According to the composition of the erbium-containing Al-Mg alloy (the same as in Example 3), high-purity aluminum ingots, high-purity magnesium ingots, and intermediate alloys Al-Mn, Al-Cr, Al-Ti, Al-Zr and Al-Er are added to a vacuum medium-frequency induction furnace and vacuum melted at 740°C. Then, the erbium-containing Al-Mg alloy ingot is obtained by semi-continuous casting at 720-740°C.

[0055] (2) Erbium-containing Al-Mg alloy ingots are subjected to two-stage homogenization annealing and cooled to room temperature to obtain homogenized annealed erbium-containing Al-Mg alloy; wherein the first stage homogenization temperature of the two-stage homogenization annealing is 350℃ and the time is 6h; the second stage homogenization temperature is 490℃ and the time is 14h.

[0056] (3) The homogenized annealed erbium-containing Al-Mg alloy was rapidly heated to 350℃ and held for 1 hour for isothermal annealing, and then air-cooled to obtain the erbium-containing Al-Mg alloy.

[0057] The stress-strain curves of the Al-Mg alloy material in this comparative example are shown below. Figure 6 The Al-Mg alloy has a tensile strength of 246.03 MPa, a yield strength of 124.71 MPa, an elongation of 4.85%, and a hardness of 77.62 HV0.2.

[0058] Compared with the Al-Mg alloy material in the comparative example, the erbium-containing Al-Mg alloy material prepared in Example 3 showed an increase in tensile strength of 12.32%, yield strength of 22.3%, elongation of 41.86%, and hardness of 12.73%. After homogenization annealing, the as-cast segregation structure was eliminated. During the slow heating stage at 6℃ / min, the driving force for the precipitation of strengthening phase increased, and the dispersed Al3Er or Al3(Er,Zr) particles had a strong pinning effect, which improved the strength and hardness of the alloy. Since the alloy was slowly heated and not exposed to the thermal environment for a long time (the heating stage was only 54 minutes), the particle pinning effect prevented grain growth.

[0059] The specific embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A method for preparing an erbium-containing Al-Mg alloy, characterized in that, The specific steps are as follows: (1) The erbium-containing Al-Mg alloy is prepared according to its composition, vacuum melted at a temperature of 740~770℃, and then semi-continuously cast at a temperature of 720~750℃ to obtain an erbium-containing Al-Mg alloy ingot; the erbium-containing Al-Mg alloy contains 4.5~5.5 wt.% Mg, 0.4~0.8 wt.% Mn, 0.1~0.25 wt.% Zn, 0.1~0.25 wt.% Cr, 0.05~0.15 wt.% Ti, 0.1~0.3 wt.% Zr, 0.1~0.4 wt.% Er, ≤0.2 wt.% Fe, ≤0.2 wt.% Si, with the balance being Al; (2) Erbium-containing Al-Mg alloy ingots are subjected to two-stage homogenization annealing and cooled to room temperature to obtain homogenized annealed erbium-containing Al-Mg alloy; the first stage homogenization temperature of the two-stage homogenization annealing is 300~350℃ and the time is 6~10 h; the second stage homogenization temperature is 450~490℃ and the time is 12~18 h. (3) The homogenized annealed erbium-containing Al-Mg alloy is heated at a constant temperature of 2~10℃ / min to a temperature of 200~400℃ for non-isothermal annealing, and then air-cooled to obtain the erbium-containing Al-Mg alloy.

2. The method for preparing the erbium-containing Al-Mg alloy according to claim 1, characterized in that: Al was added in the form of pure aluminum, and Mg was added in the form of pure magnesium; Mn, Cr, Ti, Zr and Er were added in the form of master alloys Al-Mn, Al-Cr, Al-Ti, Al-Zr and Al-Er, respectively.

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