CN117448636A - Preparation and processing method of high heat-resistant dispersion strengthening Al-Mg-Mn-Zr-Cr-Mo alloy - Google Patents

Abstract

The invention relates to a preparation and processing method of a high heat-resistant dispersion strengthening Al-Mg-Mn-Zr-Cr-Mo alloy, belonging to the field of aluminum alloy processing and manufacturing; the alloy consists of the following components: mg:2.0 to 6.0 percent, mn:0.5 to 1.5 percent, zr:0.1 to 0.5 percent, cr:0.1 to 0.5 percent, mo:0.1 to 0.5 percent, and the balance of aluminum and unavoidable impurities; the preparation method comprises the following steps: smelting to obtain as-cast alloy, creatively using high-temperature pre-ageing treatment aiming at alloy characteristics, wherein the pre-ageing temperature is 200-300 ℃ for 8-36 h, and then cooling; and (3) pre-deforming the pre-aged sample at room temperature by 2-15%, then performing artificial aging hardening treatment, and finally performing hot rolling treatment. The invention discloses a high heat-resistant dispersion strengthening Al-Mg-Mn-Zr-Cr-Mo alloy, creatively combines high-temperature pre-ageing treatment and pre-deformation treatment, can effectively shorten the time for reaching peak strength of the alloy on one hand, and can effectively improve the dispersion strengthening effect of the alloy on the other hand, so that the mechanical property is far higher than that of the conventional heat-resistant aluminum alloy at present, and the application range of the heat-resistant aluminum alloy is expanded.

Description

Preparation and processing of a highly heat-resistant dispersion-strengthened Al-Mg-Mn-Zr-Cr-Mo alloy method

Technical field

The invention relates to a preparation and processing method of a highly heat-resistant dispersion-strengthened Al-Mg-Mn-Zr-Cr-Mo alloy, belonging to the field of aluminum alloy processing and manufacturing.

Background technique

5000 series Al-Mg-based alloys are widely used in fields such as marine ships, automotive parts and welded structural parts due to their good combination of high specific strength, high stiffness, corrosion resistance and weldability. Traditional 5xxx series aluminum alloys are non-age-strengthenable aluminum alloys, which obtain medium strength mainly through solid solution strengthening and work hardening of solute Mg atoms.

In order to improve the mechanical properties of non-age-hardenable aluminum alloys, dispersion strengthening is achieved by adding micro-alloying elements. Therefore, by adding Mn element to the 5000 series aluminum alloy, we achieve the decomposition of the supersaturated solid solution during the heat treatment process, thereby producing a Mn dispersed phase containing a complex crystal structure. These Mn-containing dispersed phases may obtain additional dispersion strengthening effects in traditional non-age-strengthenable aluminum alloys. Generally speaking, the dispersion strengthening effect of these dispersed phases mainly depends on their type, morphology, size and number density in the matrix, all of which vary significantly with different microalloying and processing processes.

At present, different single-stage and multi-stage aging treatments are mainly used to promote the precipitation of Mn-containing dispersed phases in Al-Mg-Mn alloys. However, the existing heat treatment process alone cannot achieve obvious dispersion strengthening effects. On the other hand, the uneven distribution of Mn-containing dispersed phases is a common phenomenon after aging treatment of Mn-containing aluminum alloys. Due to microsegregation during the solidification process, a non-dispersed precipitation zone will be formed at the center of the dendrites, which will further weaken its dispersion strengthening effect. However, traditional aging treatment is difficult to reduce or eliminate the non-dispersed precipitation zone in the center of dendrites. Therefore, there is an urgent need to develop other solutions to achieve better dispersion strengthening effects of Mn-containing dispersed phases in 5000 alloy. In addition, in order to ensure the thermal stability of alloy materials under high-temperature service conditions, it is imperative to further improve the high-temperature thermal stability of the Mn-rich dispersed phase.

Contents of the invention

The purpose of the present invention is to provide a preparation and processing method of a highly heat-resistant dispersion-strengthened Al-Mg-Mn-Zr-Cr-Mo alloy, aiming to improve the aging response capability and strength of the heat-resistant dispersion-strengthened aluminum alloy.

In order to achieve the above objects, the present invention adopts the following technical solutions:

The invention provides a highly heat-resistant dispersion-strengthened Al-Mg-Mn-Zr-Cr-Mo alloy. In terms of mass percentage: Mg: 2.0-6.0%, Mn: 0.5-1.5%, Zr: 0.1-0.5%. Cr: 0.1~0.5%, Mo: 0.1~0.5%, the balance is aluminum and unavoidable impurities; the impurities are derived from raw materials and are unavoidable. The impurity content is: Si: 0.1-0.5%, Fe: 0.1-0.5 %, Cu≤0.05%, Zn≤0.05%.

The invention also provides a preparation and processing method of the Al-Mg-Mn-Zr-Cr-Mo alloy, which includes the following steps:

Mix ingredients according to the ingredient ratio to obtain mixed raw materials;

The mixed raw materials are heated and melted and then poured to obtain an ingot;

The ingot alloy is pre-aged at high temperature and then cooled; the pre-aged sample is pre-deformed, then artificially aged and hardened, and finally hot-rolled to obtain a rolled plate.

Preferably, the process of obtaining the ingot is specifically:

Heat the mixed raw materials to 850-900°C, keep the temperature for 30-50 minutes after melting, cool to 740-760°C for argon degassing, and let the resulting melt stand for slag removal before pouring it into the preheated oven at 730-750°C. to a mold at 200-250°C to obtain an ingot.

Preferably, the pre-aging temperature is between 200-300°C, the holding time is 0.5-36h, and then air-cooled or quenched to room temperature.

Preferably, the pre-deformation process is room temperature cold rolling deformation, the pass reduction is 1 to 3%, and the total reduction is 5 to 15%; or the pre-deformation process is room temperature pre-stretching, and the stretching rate is 1×10 ^-3 s ^-1 , the strain is 2~6%;

Preferably, the artificial aging hardening treatment is performed at a temperature of 400 to 425°C and a time of 4 to 24 hours.

Preferably, the hot rolling temperature is 280-320°C, the pass reduction is 5-10%, and the total reduction is 65%-75%.

Beneficial effects:

1. The present invention discloses a highly heat-resistant dispersion-strengthened Al-Mg-Mn-Zr-Cr-Mo alloy, which utilizes multi-component synergistic micro-alloying of Zr, Cr, and Mo to promote nanoscale α phase and Al ₃ Zr dispersed particles. The precipitation will help improve the room temperature and high temperature strength of the alloy.

2. The present invention also discloses a preparation and processing method of Al-Mg-Mn-Zr-Cr-Mo alloy, which uses the synergistic effect of pre-aging + pre-straining on the as-cast alloy to suppress the formation of non-dispersed particle precipitation zones in the alloy. Form, and increase the precipitation density of the dispersed phase and refine the size of the dispersed phase, thereby improving the strength of the alloy,

Description of the drawings

Figure 1 shows the hardness changes of the alloys of Example 1, Reference Example 1 and Reference Example 2 after different pretreatment methods during the aging treatment at 400°C.

Figure 2 is a TEM bright field image of the alloy of Example 1 after aging treatment at 400°C for 12 hours.

Figure 3 is a TEM bright field image of the alloy of Reference Example 1 after aging treatment at 400°C for 12 hours.

Figure 4 is the TEM bright field image of the alloy in Reference Example 2 after aging treatment at 400°C for 12 hours.

Specific implementation methods

The present invention will be described in detail below with reference to specific examples. The following examples will help researchers in the field further understand the present invention, but do not limit the present invention in any form. It should be noted that, without departing from the concept of the present invention, several improvements can still be made, and these all belong to the protection scope of the present invention.

Example 1

The preparation and processing method of a highly heat-resistant dispersion strengthened Al-Mg-Mn-Zr-Cr-Mo alloy in this embodiment includes the following steps:

Step 1. Prepare Al-Mg-Mn-Zr-Cr-Mo alloy, in which the alloy composition is: Mg: 4.0%, Mn: 1.0%, Zr: 0.2%, Cr: 0.2%, Mo: 0.2%, and the balance is Aluminum and unavoidable impurities, of which the impurities originate from raw materials and are unavoidable, the impurity content is: Fe: 0.3%, Si: 0.2%, Cu: 0.05%, Zn: 0.05%. After batching, heat the raw materials to 875°C. After complete melting, keep the temperature for 40 minutes and stir with a stone grinding rod several times. Then cool to 750°C and perform argon degassing for 3 to 5 minutes. After the melt is left to stand and the slag is removed, it is heated to 730 to 730°C. Pour at 750°C into a mold preheated to 200°C (steel mold, copper mold, graphite mold can be used) to obtain an ingot;

Step 2: Pre-age the as-cast Al-Mg-Mn-Zr-Cr-Mo alloy obtained in Step 1 at 300°C. The pre-aging treatment time is 8 hours, and air-cooled to room temperature;

Step 3. Carry out room temperature cold rolling on the alloy sheet obtained in step 2, with a pass reduction of 2%, a rolling speed of 0.1ms ^-1 and a total reduction of 10%;

Step 4: Perform isothermal aging treatment on the alloy obtained in Step 3 at 400°C.

Step 5: Hot-roll the alloy obtained after aging treatment at 400°C for 12 hours in Step 4. The rolling temperature is 320°C, the pass reduction is 10%, and the total reduction is 70%.

Figure 1 shows the hardness change curve of the alloy during the aging process in step 4. Figure 2 is the TEM bright field image of the alloy after aging treatment at 400°C for 12 hours in step 4. Table 2 shows the statistical distribution of precipitated phases after the alloy was aged at 400°C for 12 hours in step 4. After the alloy in step 4 is aged at 400°C for 12 hours, the tensile mechanical properties at room temperature are tested. The tensile properties are shown in Table 1. The final yield strength is 178.5±2.5MPa, the tensile strength is 291.9±10.8MPa, and the elongation is 7.1±0.5%. Conduct room temperature tensile mechanical properties test on the alloy obtained in step 5. The tensile properties are shown in Table 1. The final yield strength is 310.5±1.3MPa, the tensile strength is 395.6±8.7MPa, and the elongation is 11.1±0.6%. The alloy obtained in step 5 was subjected to a high temperature tensile mechanical property test at 300°C. The tensile properties are shown in Table 3. The final yield strength is 119.2±2.8MPa, the tensile strength is 119.2±2.8MPa, and the elongation is 45.5±5.6%.

Example 2

The preparation and processing method of a highly heat-resistant dispersion strengthened Al-Mg-Mn-Zr-Cr-Mo alloy in this embodiment includes the following steps:

Step 1. Prepare Al-Mg-Mn-Zr-Cr-Mo alloy, where the alloy composition is: Mg: 4.0%, Mn: 1.0%, Zr: 0.2%, Cr: 0.2%, Mo: 0.1%, and the balance is Aluminum and unavoidable impurities, of which the impurities originate from raw materials and are unavoidable, the impurity content is: Fe: 0.3%, Si: 0.2%, Cu: 0.05%, Zn: 0.05%. After batching, heat the raw materials to 875°C. After complete melting, keep the temperature for 40 minutes and stir with a stone grinding rod several times. Then cool to 750°C and perform argon degassing for 3 to 5 minutes. After the melt is left to stand and the slag is removed, it is heated to 730 to 730°C. Pour at 750°C into a mold preheated to 200°C (steel mold, copper mold, graphite mold can be used) to obtain an ingot;

Step 2: Pre-age the as-cast Al-Mg-Mn-Zr-Cr-Mo alloy obtained in Step 1 at 200°C. The pre-aging treatment time is 36 hours and quenched to room temperature;

Step 3. Carry out room temperature cold rolling on the alloy obtained in step 2, with a pass reduction of 3%, a rolling speed of 0.1ms ^-1 and a total reduction of 15%;

Step 4. Aging treatment is performed on the alloy obtained in Step 3 at 425°C, and the aging treatment time is 12 hours.

Step 5: Hot-roll the alloy obtained in Step 4. The rolling temperature is 300°C, the pass reduction is 10%, and the total reduction is 75%.

Conduct room temperature tensile mechanical properties test on the alloy obtained in step 4. The tensile properties are shown in Table 1. The final yield strength is 175.5±3.6MPa, the tensile strength is 286.9±8.7MPa, and the elongation is 6.2±1.3%. Conduct room temperature tensile mechanical properties test on the alloy obtained in step 5. The tensile properties are shown in Table 1. The final yield strength is 304.6±2.6MPa, the tensile strength is 393.8±6.2MPa, and the elongation is 10.2±0.7%.

Example 3

The preparation and processing method of a highly heat-resistant dispersion strengthened Al-Mg-Mn-Zr-Cr-Mo alloy in this embodiment includes the following steps:

Step 1. Prepare Al-Mg-Mn-Zr-Cr-Mo alloy, in which the alloy composition is: Mg: 4.0%, Mn: 1.0%, Zr: 0.2%, Cr: 0.1%, Mo: 0.1%, and the balance is Aluminum and unavoidable impurities, of which the impurities originate from raw materials and are unavoidable, the impurity content is: Fe: 0.3%, Si: 0.2%, Cu: 0.05%, Zn: 0.05%. After batching, heat the raw materials to 875°C. After complete melting, keep the temperature for 40 minutes and stir with a stone grinding rod several times. Then cool to 750°C and perform argon degassing for 3 to 5 minutes. After the melt is left to stand and the slag is removed, it is heated to 730 to 730°C. Pour at 750°C into a mold preheated to 200°C (steel mold, copper mold, graphite mold can be used) to obtain an ingot;

Step 2: Pre-age the as-cast Al-Mg-Mn-Zr-Cr-Mo alloy obtained in Step 1 at 300°C. The pre-aging treatment time is 30 minutes and quenched to room temperature;

Step 3. Tensile the alloy obtained in Step 2 at room temperature, with a strain rate of 1×10 ^-3 s ^-1 and a strain of 6%;

Step 4. Perform aging treatment on the alloy obtained in step 3 at 400°C, and the aging treatment time is 24 hours.

Step 5: Hot-roll the alloy obtained in Step 4. The rolling temperature is 300°C, the pass reduction is 10%, and the total reduction is 70%.

Conduct room temperature tensile mechanical properties test on the alloy obtained in step 4. The tensile properties are shown in Table 1. The final yield strength is 176.3±2.4MPa, the tensile strength is 289.3±5.5MPa, and the elongation is 6.7±0.8%. Conduct room temperature tensile mechanical properties test on the alloy obtained in step 5. The tensile properties are shown in Table 1. The final yield strength is 305.7±3.8MPa, the tensile strength is 393.7±4.2MPa, and the elongation is 9.6±1.1%.

Example 4

The preparation and processing method of a highly heat-resistant dispersion strengthened Al-Mg-Mn-Zr-Cr-Mo alloy in this embodiment includes the following steps:

Step 1. Prepare Al-Mg-Mn-Zr-Cr-Mo alloy, where the alloy composition is: Mg: 4.0%, Mn: 1.0%, Zr: 0.2%, Cr: 0.1%, Mo: 0.2%, and the balance is Aluminum and unavoidable impurities, of which the impurities originate from raw materials and are unavoidable, the impurity content is: Fe: 0.3%, Si: 0.2%, Cu: 0.05%, Zn: 0.05%. After batching, heat the raw materials to 875°C. After complete melting, keep the temperature for 40 minutes and stir with a stone grinding rod several times. Then cool to 750°C and perform argon degassing for 3 to 5 minutes. After the melt is left to stand and the slag is removed, it is heated to 730 to 730°C. Pour at 750°C into a mold preheated to 200°C (steel mold, copper mold, graphite mold can be used) to obtain an ingot;

Step 2: Pre-age the as-cast Al-Mg-Mn-Zr-Cr-Mo alloy obtained in Step 1 at 300°C. The pre-aging treatment time is 12 hours, and air-cooled to room temperature;

Step 3. Tensile the alloy obtained in Step 2 at room temperature, with a strain rate of 1×10 ^-3 s ^-1 and a strain of 6%;

Step 4. Aging treatment is performed on the alloy obtained in step 3 at 425°C, and the aging treatment time is 24 hours.

Step 5: Hot-roll the alloy obtained in Step 4. The rolling temperature is 300°C, the pass reduction is 10%, and the total reduction is 70%.

Conduct room temperature tensile mechanical properties test on the alloy obtained in step 4. The tensile properties are shown in Table 1. The final yield strength is 175.8±1.9MPa, the tensile strength is 288.9±6.3MPa, and the elongation is 6.3±0.7%. Conduct room temperature tensile mechanical properties test on the alloy obtained in step 5. The tensile properties are shown in Table 1. The final yield strength is 301.8±5.1MPa, the tensile strength is 388.4±6.1MPa, and the elongation is 9.3±0.8%.

Comparative example 1

This comparative example uses a highly heat-resistant dispersion-strengthened Al-Mg-Mn-Zr-Cr-Mo alloy as a research example, including the following steps:

Step 1. Prepare Al-Mg-Mn-Zr-Cr-Mo alloy, in which the alloy composition is: Mg: 4.0%, Mn: 1.0%, Zr: 0.2%, Cr: 0.2%, Mo: 0.2%, and the balance is Aluminum and unavoidable impurities, of which the impurities originate from raw materials and are unavoidable, the impurity content is: Fe: 0.3%, Si: 0.2%, Cu: 0.05%, Zn: 0.05%. After batching, heat the raw materials to 875°C. After complete melting, keep the temperature for 40 minutes and stir with a stone grinding rod several times. Then cool to 750°C and perform argon degassing for 3 to 5 minutes. After the melt is left to stand and the slag is removed, it is heated to 730 to 730°C. Pour at 750°C into a mold preheated to 200°C (steel mold, copper mold, graphite mold can be used) to obtain an ingot;

Step 2. Cold-roll the alloy obtained in Step 1 at room temperature with a pass reduction of 2%, a rolling speed of 0.1ms ^-1 and a total reduction of 10%;

Step 3: Aging treatment is performed on the alloy obtained in Step 2 at 400°C.

Step 4: Hot-roll the alloy obtained after aging treatment at 400°C for 12 hours in step 3. The rolling temperature is 320°C, the pass reduction is 10%, and the total reduction is 70%.

Figure 1 shows the hardness change curve of the alloy during the aging process in step 3. Figure 3 is the TEM bright field image of the alloy after aging treatment at 400°C for 12 hours in step 3. Table 2 shows the statistical distribution of precipitated phases after the alloy was aged at 400°C for 12 hours in step 3. After the alloy in step 3 is aged at 400°C for 12 hours, the tensile mechanical properties at room temperature are tested. The tensile properties are shown in Table 1. The final yield strength is 173.9±1.1MPa, the tensile strength is 251.0±8.5MPa, and the elongation is 5.4±0.6%. Conduct room temperature tensile mechanical properties test on the alloy obtained in step 4. The tensile properties are shown in Table 1. The final yield strength is 290.4±2.6MPa, the tensile strength is 361.5±5.4MPa, and the elongation is 12.5±0.7%.

Comparative example 2

This comparative example uses a highly heat-resistant dispersion-strengthened Al-Mg-Mn-Zr-Cr-Mo alloy as a research example, including the following steps:

Step 1. Prepare Al-Mg-Mn-Zr-Cr-Mo alloy, in which the alloy composition is: Mg: 4.0%, Mn: 1.0%, Zr: 0.2%, Cr: 0.2%, Mo: 0.2%, and the balance is Aluminum and unavoidable impurities, of which the impurities originate from raw materials and are unavoidable, the impurity content is: Fe: 0.3%, Si: 0.2%, Cu: 0.05%, Zn: 0.05%. After batching, heat the raw materials to 875°C. After complete melting, keep the temperature for 40 minutes and stir with a stone grinding rod several times. Then cool to 750°C and perform argon degassing for 3 to 5 minutes. After the melt is left to stand and the slag is removed, it is heated to 730 to 730°C. Pour at 750°C into a mold preheated to 200°C (steel mold, copper mold, graphite mold can be used) to obtain an ingot;

Step 2: Aging treatment is performed on the alloy obtained in Step 1 at 400°C.

Step 3: Hot-roll the alloy obtained after aging treatment at 400°C for 12 hours in step 2. The rolling temperature is 320°C, the pass reduction is 10%, and the total reduction is 70%.

Figure 1 shows the hardness change curve of the alloy during the aging process in step 2. Figure 4 is the TEM bright field image of the alloy after aging treatment at 400°C for 12 hours in step 2. Table 2 shows the statistical distribution of precipitated phases after the alloy was aged at 400°C for 12 hours in step 2. After the alloy in step 2 is aged at 400°C for 12 hours, the tensile mechanical properties at room temperature are tested. The tensile properties are shown in Table 1. The final yield strength is 133.4±5.1MPa, the tensile strength is 208.5±15.7MPa, and the elongation is 5.8±0.8%. Conduct room temperature tensile mechanical properties test on the alloy obtained in step 3. The tensile properties are shown in Table 1. The final yield strength is 252.8±3.4MPa, the tensile strength is 321.8±6.7MPa, and the elongation is 9.8±2.1%.

Comparative example 3

This comparative example uses a highly heat-resistant dispersion-strengthened Al-Mg-Mn-Zr-Cr-Mo alloy as a research example, including the following steps:

Step 1. Prepare Al-Mg-Mn-Zr-Cr-Mo alloy, where the alloy composition is: Mg: 4.0%, Mn: 1.0%, Zr: 0.2%, Cr: 0.2%, Mo: 0.1%, and the balance is Aluminum and unavoidable impurities, of which the impurities originate from raw materials and are unavoidable, the impurity content is: Fe: 0.3%, Si: 0.2%, Cu: 0.05%, Zn: 0.05%. After batching, heat the raw materials to 875°C. After complete melting, keep the temperature for 40 minutes and stir with a stone grinding rod several times. Then cool to 750°C and perform argon degassing for 3 to 5 minutes. After the melt is left to stand and the slag is removed, it is heated to 730 to 730°C. Pour at 750°C into a mold preheated to 200°C (steel mold, copper mold, graphite mold can be used) to obtain an ingot;

Step 2: Pre-age the as-cast Al-Mg-Mn-Zr-Cr-Mo alloy obtained in Step 1 at 200°C. The pre-aging treatment time is 24h and quenched to room temperature;

Step 3. Aging treatment is performed on the alloy obtained in Step 2 at 400°C, and the aging treatment time is 20 hours.

Step 4: Hot-roll the alloy obtained in Step 3. The rolling temperature is 300°C, the pass reduction is 10%, and the total reduction is 70%.

Conduct room temperature tensile mechanical properties test on the alloy obtained in step 3. The tensile properties are shown in Table 1. The final yield strength is 151.4±3.1MPa, the tensile strength is 220.4±8.6MPa, and the elongation is 5.6±0.7%. Conduct room temperature tensile mechanical properties test on the alloy obtained in step 4. The tensile properties are shown in Table 1. The final yield strength is 252.8±3.4MPa, the tensile strength is 321.8±6.7MPa, and the elongation is 9.8±2.1%.

Comparative example 4

This comparative example uses an Al-Mg-Mn-Zr-Cr alloy as a research example, including the following steps:

Step 1. Prepare Al-Mg-Mn-Zr-Cr alloy, in which the alloy composition is: Mg: 4.0%, Mn: 1.0%, Zr: 0.2%, Cr: 0.1%, and the balance is aluminum and inevitable impurities. The impurities originate from the raw materials and are unavoidable. The impurity contents are: Fe: 0.3%, Si: 0.2%, Cu: 0.05%, and Zn: 0.05%. After batching, heat the raw materials to 780°C. After complete melting, keep the temperature for 40 minutes and stir with a stone grinding rod several times. Then cool to 750°C and perform argon degassing for 3 to 5 minutes. After the melt is allowed to stand and the slag is removed, it is heated to 730 to 730°C. Pour at 750°C into a mold preheated to 200°C (steel mold, copper mold, graphite mold can be used) to obtain an ingot;

Step 2: Pre-age the as-cast Al-Mg-Mn-Zr-Cr alloy obtained in Step 1 at 300°C. The pre-aging treatment time is 8 hours, and air-cooled to room temperature;

Step 3. Carry out room temperature cold rolling on the alloy sheet obtained in step 2, with a pass reduction of 2%, a rolling speed of 0.1ms ^-1 and a total reduction of 10%;

Step 4: Aging treatment is performed on the alloy obtained in step 3 at 400°C, and the aging treatment time is 12 hours.

Step 5: Hot-roll the alloy obtained in Step 4. The rolling temperature is 320°C, the pass reduction is 10%, and the total reduction is 70%.

Conduct room temperature tensile mechanical properties test on the alloy obtained in step 4. The tensile properties are shown in Table 1. The final yield strength is 165.5±2.6MPa, the tensile strength is 282.4±5.7MPa, and the elongation is 6.4±1.3%. Conduct room temperature tensile mechanical properties test on the alloy obtained in step 5. The tensile properties are shown in Table 1. The final yield strength is 281.8±2.5MPa, the tensile strength is 375.7±8.7MPa, and the elongation is 9.7±2.4%. The alloy obtained in step 5 was subjected to a high temperature tensile mechanical property test at 300°C. The tensile properties are shown in Table 3. The final yield strength is 91.3±3.7MPa, the tensile strength is 91.3±3.7MPa, and the elongation is 37.2±4.9%.

Table 1. Comparison of room temperature tensile properties test in corresponding states of each example and comparative example.

Table 2. Statistical distribution of precipitated phases in corresponding states of each example and comparative example.

alloy state Equivalent radius/nm Number density/m ^-3 Volume fraction/% Example 1 400℃/12h 40.2 6.4×10 ²⁰ 17.5 Comparative example 1 400℃/12h 50.6 3.3×10 ²⁰ 17.7 Comparative example 2 400℃/12h 80.8 5.2×10 ¹⁹ 12.1

Table 3. Comparison of 300°C high-temperature tensile properties test in corresponding states of each example and comparative example.

It can be seen from Table 1 and Table 3 that compared with Comparative Example 4, Example 1 shows stronger heat resistance. This is mainly due to the synergistic micro-alloying of Zr, Cr, Mo, etc., which promotes high precipitation. The dense nanoscale α phase and Al ₃ Zr dispersed particles directly provide considerable strength; during the subsequent rolling and annealing process, their indirect strengthening effect of inhibiting recrystallization is still retained, so the strength of the final product is greatly improved.

It can be seen from Figure 1 that after the alloy of Example 1 undergoes pre-aging + pre-deformation treatment, compared with the as-cast alloy of Comparative Example 2, its hardness is significantly improved and the time to reach peak hardness is significantly shortened. Compared with the alloy of Comparative Example 1 that has only undergone pre-deformation, the hardness at each aging stage has been improved to a certain extent. At the same time, we can see that after long-term high-temperature aging treatment, the hardness of the alloy in Example 1 can still maintain a high level. This shows that the pre-aging + pre-deformation treatment process can accelerate the aging response process of Al-Mg-Mn-Zr-Cr-Mo alloy, while further improving the dispersion strengthening effect of the alloy and maintaining high heat resistance.

It can be seen from Figure 2-4 that after the alloy undergoes pre-aging + pre-deformation treatment process, the distribution of precipitated phases is significantly refined and the quantity is significantly increased. In the two alloys containing the predeformation treatment process, the distribution of precipitated phases along the dislocation lines can be observed, which shows that the predeformation process can increase the nucleation sites of α phase by introducing dislocations and improve the dispersion strengthening effect of the alloy. It can be seen from Table 2 that compared to Comparative Example 1 and Comparative Example 2, the precipitated phase in Example 1 has a significantly higher number density and smaller size, indicating that the pre-aging + pre-deformation treatment process can effectively promote the α phase. precipitation, which is consistent with the hardness change in Figure 1.

In summary, the present invention discloses a preparation and processing method of a highly heat-resistant dispersion-strengthened Al-Mg-Mn-Zr-Cr-Mo alloy. First, the synergistic micro-alloying of Zr, Cr, and Mo is used to promote nanoscale The precipitation of α phase and Al ₃ Zr dispersed particles is beneficial to improving the room temperature and high temperature strength of the alloy. Secondly, the combination of pre-deformation and pre-aging can effectively shorten the time for the alloy to reach peak strength on the one hand, and on the other hand can effectively improve the dispersion strengthening effect of the alloy, making the mechanical properties far exceed the current conventional Al-Mg-Mn alloy, expanding the Al -Application range of Mg-Mn alloy.

The above-mentioned specific description further explains the purpose, technical solutions and beneficial effects of the invention in detail. It should be understood that the above-mentioned are only specific embodiments of the invention and are not intended to limit the protection of the invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims (7)

1. A high heat-resistant dispersion strengthening Al-Mg-Mn-Zr-Cr-Mo alloy is characterized in that: the components are as follows by mass percent: mg:2.0 to 6.0 percent, mn:0.5 to 1.5 percent, zr:0.1 to 0.5 percent, cr:0.1 to 0.5 percent, mo:0.1 to 0.5 percent, and the balance of aluminum and unavoidable impurities; wherein the impurity comes from raw materials, which are unavoidable, and the impurity content is: si:0.1-0.5%, fe:0.1-0.5%, cu is less than or equal to 0.05%, and Zn is less than or equal to 0.05%.

2. A method for preparing the high heat resistant dispersion strengthened Al-Mg-Mn-Zr-Cr-Mo alloy according to claim 1, wherein: proportioning according to the component proportion to obtain a mixed raw material; pouring the mixed raw materials after heating and melting to obtain an ingot; carrying out high-temperature pre-ageing treatment on the cast ingot alloy, and then cooling; and pre-deforming the sample after the pre-ageing treatment, then performing artificial ageing hardening treatment, and finally performing hot rolling treatment to obtain the rolled plate.

3. The method of claim 2, wherein: the method for heating and melting comprises the following steps: heating the mixed raw materials to 850-900 ℃, preserving heat for 30-50 min after melting, cooling to 740-760 ℃ for flowing argon and degassing, standing the obtained melt for slag skimming, and pouring the obtained melt into a die preheated to 200-250 ℃ at 730-750 ℃ to obtain an ingot.

4. The method of claim 2, wherein: the high-temperature pre-ageing treatment method comprises the following steps: and (3) placing the ingot alloy at the temperature of 200-300 ℃, preserving the heat for 0.5-36h, and then air-cooling or quenching to room temperature.

5. The method of claim 2, wherein: the pre-deformation process is as followsCold rolling at room temperature to form deformation, wherein the pass rolling reduction is 1-3% and the total rolling reduction is 5-15%; or preshaping at room temperature at a stretching rate of 1×10 ^-3 s ^-1 The strain is 2-6%.

6. A method according to claim 2, characterized in that: the temperature of the artificial aging hardening treatment is 400-425 ℃ and the time is 4-24 hours.

7. A method according to claim 2, characterized in that: the temperature of the hot rolling is 280-320 ℃, the pass reduction is 5-10%, and the total reduction is 65% -75%.