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

Abstract

The application relates to a high-heat-resistance dispersion strengthening type Al-Mg-Mn-Zr-Cr-Mo alloy preparation and processing method and belongs to the field of aluminum alloy processing and manufacturing; the alloy is composed of the following components: 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%, and the balance is aluminum and inevitable impurities; the preparation method comprises the following steps: firstly, melting to obtain a cast alloy, then innovatively using high-temperature pre-aging treatment according to the alloy characteristics, the pre-aging temperature is 200-300 DEG C, the time is 8-36h, and then cooling; the pre-aging treated sample is subjected to room temperature pre-deformation, the deformation amount is 2-15%, then artificial aging hardening treatment is carried out, and finally hot rolling treatment is carried out. The application discloses a high-heat-resistance dispersion strengthening type Al-Mg-Mn-Zr-Cr-Mo alloy, and innovatively combines high-temperature pre-aging treatment and pre-deformation treatment, which can effectively shorten the time for the alloy to reach the peak strength, effectively improve the dispersion strengthening effect of the alloy, make the mechanical properties far exceed those of the current conventional heat-resistant aluminum alloy, and expand the application range of the heat-resistant aluminum alloy.

Description

TECHNICAL FIELD

[0001] The application relates to a high-heat-resistance dispersion-strengthened Al-Mg-Mn-Zr-Cr-Mo alloy preparation and processing method and belongs to the field of aluminum alloy processing and manufacturing. BACKGROUND

[0002] 5000 series Al-Mg base alloys are widely used in marine ships, automobile parts and welded structural parts and the like due to the good combination of high specific strength, high rigidity, corrosion resistance and weldability. Traditional 5xxx series aluminum alloys belong to non-ageing-strengthened aluminum alloys, and the medium strength thereof is obtained through solid solution strengthening of solute Mg atoms and work hardening.

[0003] In order to improve the mechanical properties of the non-ageing-strengthened aluminum alloy, people realize dispersion strengthening by adding micro-alloying elements. Therefore, the application adds Mn elements to the 5000 series aluminum alloy, realizes decomposition of the supersaturated solid solution in the heat treatment process, and thus generates Mn dispersion phases containing complex crystal structures. These Mn-containing dispersion phases are likely to obtain additional dispersion strengthening effect in the traditional non-ageing-strengthened aluminum alloy. Generally, the dispersion strengthening effect of these dispersion phases mainly depends on their type, morphology, size and number density in the matrix, and all of them change significantly with different micro-alloying and processing processes.

[0004] At present, different single-stage and multi-stage ageing treatments are mainly used to promote the Mn-containing dispersion phase in the Al-Mg-Mn alloy, however, the existing heat treatment process cannot achieve obvious dispersion strengthening effect. On the other hand, the uneven distribution of the Mn-containing dispersion phase is a common phenomenon after the ageing treatment of the Mn-containing aluminum alloy. Due to the microsegregation in the solidification process, the non-dispersion precipitation zone is formed at the dendrite center, which further weakens the dispersion strengthening effect. The traditional ageing treatment is difficult to reduce or eliminate the non-dispersion precipitation zone at the dendrite center. Therefore, it is urgent to develop other solutions to realize better dispersion strengthening effect of the Mn-containing dispersion phase in the 5000 alloy. In addition, in order to ensure the thermal stability of the alloy material in the high-temperature service state, it is imperative to further improve the high-temperature thermal stability of the Mn-rich dispersion phase. SUMMARY

[0005] The application aims to provide a high-heat-resistance dispersion-strengthened Al-Mg-Mn-Zr-Cr-Mo alloy preparation and processing method, and aims to improve the ageing response ability and strength of the heat-resistance dispersion-strengthened aluminum alloy.

[0006] In order to achieve the above-mentioned purpose, the application adopts the following technical scheme:

[0007] The application provides a high-heat-resistance dispersion strengthening type Al-Mg-Mn-Zr-Cr-Mo alloy, which comprises the following components in percentage by mass: 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%, and the rest is aluminum and inevitable impurities; wherein the impurities are derived from raw materials and inevitable, and the impurity content is: Si: 0.1-0.5%, Fe: 0.1-0.5%, Cu≤0.05%, and Zn≤0.05%.

[0008] The application further provides a preparation and processing method of the Al-Mg-Mn-Zr-Cr-Mo alloy, which comprises the following steps:

[0009] According to the component proportion, the mixed raw materials are obtained;

[0010] The mixed raw materials are heated and melted to obtain ingots;

[0011] The ingot alloy is subjected to high-temperature pre-aging treatment, and then cooled; the pre-aging treated sample is subjected to pre-deformation, and then subjected to artificial aging hardening treatment, and finally subjected to hot rolling treatment to obtain a rolling plate.

[0012] Preferably, the process of obtaining the ingot is specifically as follows:

[0013] The mixed raw materials are heated to 850-900 DEG C, melted and kept for 30-50 min, cooled to 740-760 DEG C for argon flow degassing, and then poured into a mold preheated to 200-250 DEG C at 730-750 DEG C after the obtained melt is kept and slagged to obtain the ingot.

[0014] Preferably, the pre-aging temperature is between 200-300 DEG C, the holding time is 0.5-36 h, and then air cooling or quenching to room temperature.

[0015] Preferably, the pre-deformation process is cold rolling deformation at room temperature, the pass reduction is 1-3%, and the total reduction is 5-15%; or the pre-deformation process is pre-tensioning at room temperature, the tensioning rate is 1*10 -3 s -1 , and the strain is 2-6%.

[0016] Preferably, the artificial aging hardening treatment is at a temperature of 400-425 DEG C for 4-24 h.

[0017] Preferably, the hot rolling temperature is 280-320 DEG C, the pass reduction is 5-10%, and the total reduction is 65%-75%.

[0018] Beneficial effects:

[0019] 1. The application discloses a high-heat-resistance dispersion-strengthened Al-Mg-Mn-Zr-Cr-Mo alloy. The Zr, Cr and Mo multi-element synergistic micro-alloying promotes the precipitation of nanoscale α phase and Al3Zr dispersion particles, and is beneficial to improving the room-temperature and high-temperature strength of the alloy.

[0020] 2. The application further discloses a preparation and processing method of the Al-Mg-Mn-Zr-Cr-Mo alloy. The pre-aging and pre-strain synergistic effect is used to inhibit the formation of the non-dispersion particle precipitation zone in the alloy, improve the dispersion phase precipitation density and refine the dispersion phase size, and thus improve the strength of the alloy. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 The hardness change of the alloys in Example 1, Reference Example 1 and Reference Example 2 after different pretreatment methods during the aging treatment at 400 DEG C is shown in the following table.

[0022] Figure 2 The TEM bright field image of the alloy in Example 1 after aging treatment at 400 DEG C for 12h is shown in the following figure.

[0023] Figure 3 The TEM bright field image of the alloy in Reference Example 1 after aging treatment at 400 DEG C for 12h is shown in the following figure.

[0024] Figure 4 The TEM bright field image of the alloy in Reference Example 2 after aging treatment at 400 DEG C for 12h is shown in the following figure. DETAILED DESCRIPTION

[0025] The application will be described in detail below with specific examples. The following examples will help researchers in the field further understand the application, but do not limit the application in any form. It should be pointed out that, without departing from the concept of the application, several improvements can be made, which are within the protection scope of the application.

[0026] Example 1

[0027] The preparation and processing method of the high-heat-resistance dispersion-strengthened Al-Mg-Mn-Zr-Cr-Mo alloy in the embodiment comprises the following steps.

[0028] Step 1, preparing Al-Mg-Mn-Zr-Cr-Mo alloy, wherein 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, wherein the impurities are derived from raw materials, which are unavoidable, and the impurity content is: Fe: 0.3%, Si: 0.2%, Cu: 0.05%, Zn: 0.05%. After batching, the raw materials are heated to 875℃, and after complete melting, they are kept for 40min and stirred multiple times with a stone mill rod. Then, the temperature is lowered to 750℃ for argon degassing for 3-5min. After the melt is allowed to stand and the slag is removed, it is poured into a mold (steel mold, copper mold, graphite mold) preheated to 200℃ at 730-750℃ to obtain a cast ingot;

[0029] Step 2, pre-aging treatment of the as-cast Al-Mg-Mn-Zr-Cr-Mo alloy obtained in Step 1 at 300℃. The pre-aging treatment time is 8h, and the alloy is air-cooled to room temperature;

[0030] Step 3, cold rolling of the alloy sheet obtained in Step 2 at room temperature, pass reduction of 2%, rolling speed of 0.1ms -1 , and total reduction of 10%;

[0031] Step 4, isothermal aging treatment of the alloy obtained in Step 3 at 400℃.

[0032] Step 5, hot rolling of the alloy obtained in Step 4 after aging at 400℃ for 12h, rolling temperature of 320℃, pass reduction of 10%, and total reduction of 70%.

[0033] Figure 1 The hardness change curve of the alloy in Step 4 during aging. Figure 2 TEM bright field image of the alloy in Step 4 after aging at 400℃ for 12h. Table 2 is the statistical distribution of precipitated phases of the alloy in Step 4 after aging at 400℃ for 12h. Room temperature tensile mechanical property test is performed on the alloy in Step 4 after aging at 400℃ for 12h. 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%. Room temperature tensile mechanical property test is performed 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%. High temperature tensile mechanical property test is performed on the alloy obtained in Step 5 at 300℃. 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%.

[0034] Example 2

[0035] The high heat-resistant dispersion-strengthened Al-Mg-Mn-Zr-Cr-Mo alloy preparation and processing method in this embodiment includes the following steps:

[0036] Step 1, preparing the Al-Mg-Mn-Zr-Cr-Mo alloy, wherein 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, wherein the impurities are derived from raw materials, which are unavoidable, and the impurity content is: Fe: 0.3%, Si: 0.2%, Cu: 0.05%, Zn: 0.05%. After batching, the raw materials are heated to 875°C, and after complete melting, they are kept for 40 min and stirred multiple times with a stone mill rod. Then, the temperature is lowered to 750°C for 3-5 min of argon degassing. After the melt is left to stand and the slag is removed, it is poured into a mold (steel mold, copper mold, graphite mold) preheated to 200°C at 730-750°C to obtain a cast ingot.

[0037] Step 2, pre-aging treatment of the as-cast Al-Mg-Mn-Zr-Cr-Mo alloy obtained in Step 1 at 200°C. The pre-aging treatment time is 36 h, and the quenching is to room temperature.

[0038] Step 3, cold rolling of the alloy obtained in Step 2 at room temperature, pass reduction of 3%, rolling speed of 0.1 ms -1 , total reduction of 15%;

[0039] Step 4, aging treatment of the alloy obtained in Step 3 at 425°C for 12 h.

[0040] Step 5, hot rolling of the alloy obtained in Step 4, rolling temperature of 300°C, pass reduction of 10%, and total reduction of 75%.

[0041] Room temperature tensile mechanical property testing of the alloy obtained in Step 4. The tensile properties are shown in Table 1, the final yield strength is 175.5±3.6 MPa, the tensile strength is 286.9±8.7 MPa, and the elongation is 6.2±1.3%. Room temperature tensile mechanical property testing of the alloy obtained in Step 5. The tensile properties are shown in Table 1, the final yield strength is 304.6±2.6 MPa, the tensile strength is 393.8±6.2 MPa, and the elongation is 10.2±0.7%.

[0042] Example 3

[0043] The high heat-resistant dispersion-strengthened Al-Mg-Mn-Zr-Cr-Mo alloy preparation and processing method in this embodiment includes the following steps:

[0044] Step 1, preparing Al-Mg-Mn-Zr-Cr-Mo alloy, wherein 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 inevitable impurities, wherein the impurities are derived from raw materials, which are inevitable, and the impurity content is: Fe: 0.3%, Si: 0.2%, Cu: 0.05%, Zn: 0.05%. After batching, the raw materials are heated to 875℃, and after complete melting, the melt is kept for 40min and stirred multiple times with a stone mill rod, and then the temperature is lowered to 750℃ for argon degassing for 3-5min. After the melt is left standing and the slag is removed, it is poured into a mold (steel mold, copper mold, graphite mold) preheated to 200℃ at 730-750℃ to obtain a cast ingot;

[0045] Step 2, pre-aging treatment of the as-cast Al-Mg-Mn-Zr-Cr-Mo alloy obtained in Step 1 at 300℃. The pre-aging treatment time is 30min, and the quenching is to room temperature;

[0046] Step 3, room temperature tensile test of the alloy obtained in Step 2, strain rate 1×10 -3 s -1 , strain 6%;

[0047] Step 4, aging treatment of the alloy obtained in Step 3 at 400℃, aging treatment time 24h.

[0048] Step 5, hot rolling treatment of the alloy obtained in Step 4, rolling temperature 300℃, pass reduction 10%, total reduction 70%.

[0049] The alloy obtained in Step 4 is subjected to room temperature tensile mechanical property test. 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%. The alloy obtained in Step 5 is subjected to room temperature tensile mechanical property test. 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%.

[0050] Example 4

[0051] The preparation and processing method of a high-heat-resistant dispersion-strengthened Al-Mg-Mn-Zr-Cr-Mo alloy in this embodiment includes the following steps:

[0052] Step 1, preparing an Al-Mg-Mn-Zr-Cr-Mo alloy, wherein 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 inevitable impurities, wherein the impurities are derived from raw materials, which are inevitable, and the impurity content is: Fe: 0.3%, Si: 0.2%, Cu: 0.05%, Zn: 0.05%. After batching, the raw materials are heated to 875°C, and after complete melting, they are kept for 40 min and stirred multiple times with a stone mill rod. Then, the temperature is lowered to 750°C for 3-5 min of argon degassing. After the melt is left to stand and the slag is removed, it is poured at 730-750°C into a mold (steel mold, copper mold, graphite mold) preheated to 200°C to obtain a cast ingot;

[0053] Step 2, pre-aging treatment of the as-cast Al-Mg-Mn-Zr-Cr-Mo alloy obtained in Step 1 at 300°C. The pre-aging treatment time is 12 h, and the air cooling is carried out to room temperature;

[0054] Step 3, room temperature tensile test of the alloy obtained in Step 2, strain rate 1×10 -3 s -1 , strain 6%;

[0055] Step 4, aging treatment of the alloy obtained in Step 3 at 425°C for 24 h.

[0056] Step 5, hot rolling treatment of the alloy obtained in Step 4, rolling temperature 300°C, pass reduction 10%, total reduction 70%.

[0057] The alloy obtained in Step 4 is subjected to room temperature tensile mechanical property testing. The tensile properties are shown in Table 1, the final yield strength is 175.8±1.9 MPa, the tensile strength is 288.9±6.3 MPa, and the elongation is 6.3±0.7%. The alloy obtained in Step 5 is subjected to room temperature tensile mechanical property testing. The tensile properties are shown in Table 1, the final yield strength is 301.8±5.1 MPa, the tensile strength is 388.4±6.1 MPa, and the elongation is 9.3±0.8%.

[0058] Comparative Example 1

[0059] This comparative example uses a high-heat-resistant dispersion-strengthened Al-Mg-Mn-Zr-Cr-Mo alloy as a research example, including the following steps:

[0060] Step 1, preparing an Al-Mg-Mn-Zr-Cr-Mo alloy, wherein the alloy composition is: Mg: 4.0%, Mn: 1.0%, Zr: 0.2%, Cr: 0.2%, Mo: 0.2%, and the balance being aluminum and inevitable impurities, wherein the impurities are derived from raw materials and are inevitable, and the impurity content is: Fe: 0.3%, Si: 0.2%, Cu: 0.05%, and Zn: 0.05%. After batching, the raw materials are heated to 875°C, completely melted, and then held for 40 min and stirred multiple times with a stone mill rod. Subsequently, the temperature is lowered to 750°C for argon degassing for 3-5 min. After the melt is allowed to stand and the slag is removed, the alloy is poured into a mold (steel mold, copper mold, or graphite mold) preheated to 200°C at 730-750°C to obtain a cast ingot.

[0061] Step 2, cold rolling the alloy obtained in Step 1 at room temperature, with a pass reduction of 2% and a rolling speed of 0.1 ms -1 , and a total reduction of 10%;

[0062] Step 3, aging treatment of the alloy obtained in Step 2 at 400°C.

[0063] Step 4, hot rolling treatment of the alloy obtained after aging treatment at 400°C for 12 h in Step 3, with a rolling temperature of 320°C, a pass reduction of 10%, and a total reduction of 70%.

[0064] Figure 1 Figure 3 is a hardness curve of the alloy in Step 3 during aging. Figure 3 Figure 4 is a TEM bright field image of the alloy in Step 3 after aging treatment at 400°C for 12 h. Table 2 is a statistical distribution of precipitated phases of the alloy in Step 3 after aging treatment at 400°C for 12 h. Room temperature tensile mechanical property testing was performed on the alloy in Step 3 after aging treatment at 400°C for 12 h. The tensile properties are shown in Table 1, with a final yield strength of 173.9±1.1 MPa, a tensile strength of 251.0±8.5 MPa, and an elongation of 5.4±0.6%. Room temperature tensile mechanical property testing was performed on the alloy obtained in Step 4. The tensile properties are shown in Table 1, with a final yield strength of 290.4±2.6 MPa, a tensile strength of 361.5±5.4 MPa, and an elongation of 12.5±0.7%.

[0065] Comparative Example 2

[0066] This comparative example uses a high-heat-resistant dispersion-strengthened Al-Mg-Mn-Zr-Cr-Mo alloy as a research example, including the following steps:

[0067] Step 1, preparing an Al-Mg-Mn-Zr-Cr-Mo alloy, wherein the alloy composition is: Mg: 4.0%, Mn: 1.0%, Zr: 0.2%, Cr: 0.2%, Mo: 0.2%, and the balance being aluminum and unavoidable impurities, wherein the impurities are derived from raw materials and are unavoidable, and the impurity content is: Fe: 0.3%, Si: 0.2%, Cu: 0.05%, and Zn: 0.05%. After batching, the raw materials are heated to 875°C, completely melted, and then held for 40 min and stirred multiple times with a stone mill rod. Subsequently, the temperature is lowered to 750°C for argon degassing for 3-5 min. After the melt is allowed to stand and the slag is removed, the alloy is poured at 730-750°C into a mold (steel mold, copper mold, graphite mold) preheated to 200°C to obtain a cast ingot.

[0068] Step 2, aging the alloy obtained in Step 1 at 400°C.

[0069] Step 3, hot rolling the alloy obtained after aging at 400°C for 12 h in Step 2, with a rolling temperature of 320°C and a pass reduction of 10%, and a total reduction of 70%.

[0070] Figure 1 Figure 2 is a hardness curve of the alloy in Step 2 during aging. Figure 4 Figure 3 is a TEM bright field image of the alloy in Step 2 after aging at 400°C for 12 h. Table 2 is a statistical distribution of precipitated phases of the alloy in Step 2 after aging at 400°C for 12 h. Room temperature tensile mechanical property testing was performed on the alloy in Step 2 after aging at 400°C for 12 h. The tensile properties are shown in Table 1, with a final yield strength of 133.4±5.1 MPa, a tensile strength of 208.5±15.7 MPa, and an elongation of 5.8±0.8%. Room temperature tensile mechanical property testing was performed on the alloy obtained in Step 3. The tensile properties are shown in Table 1, with a final yield strength of 252.8±3.4 MPa, a tensile strength of 321.8±6.7 MPa, and an elongation of 9.8±2.1%.

[0071] Comparative Example 3

[0072] This comparative example uses a high-heat-resistant dispersion-strengthened Al-Mg-Mn-Zr-Cr-Mo alloy as a research example, including the following steps:

[0073] Step 1, preparing an Al-Mg-Mn-Zr-Cr-Mo alloy, wherein the alloy composition is: Mg: 4.0%, Mn: 1.0%, Zr: 0.2%, Cr: 0.2%, Mo: 0.1%, and the balance being aluminum and unavoidable impurities, wherein the impurities are derived from raw materials and are unavoidable, and the impurity content is: Fe: 0.3%, Si: 0.2%, Cu: 0.05%, and Zn: 0.05%. After batching, the raw materials are heated to 875°C, completely melted, and then held for 40 min and stirred multiple times with a stone milling rod. Subsequently, the temperature is lowered to 750°C for argon degassing for 3-5 min. After the melt is allowed to stand and the slag is removed, it is poured into a mold (steel mold, copper mold, graphite mold) preheated to 200°C at 730-750°C to obtain a cast ingot;

[0074] Step 2, pre-aging treatment of the as-cast Al-Mg-Mn-Zr-Cr-Mo alloy obtained in Step 1 at 200°C. The pre-aging treatment time is 24 h, and the quenching is performed to room temperature.

[0075] Step 3, aging treatment of the alloy obtained in Step 2 at 400°C, and the aging treatment time is 20 h.

[0076] Step 4, hot rolling treatment of the alloy obtained in Step 3, and the rolling temperature is 300°C, the pass reduction is 10%, and the total reduction is 70%.

[0077] The alloy obtained in Step 3 is subjected to room temperature tensile mechanical property testing. The tensile properties are shown in Table 1, the final yield strength is 151.4±3.1 MPa, the tensile strength is 220.4±8.6 MPa, and the elongation is 5.6±0.7%. The alloy obtained in Step 4 is subjected to room temperature tensile mechanical property testing. The tensile properties are shown in Table 1, the final yield strength is 252.8±3.4 MPa, the tensile strength is 321.8±6.7 MPa, and the elongation is 9.8±2.1%.

[0078] Comparative Example 4

[0079] This comparative example uses an Al-Mg-Mn-Zr-Cr alloy as a research example, including the following steps:

[0080] Step 1, preparing Al-Mg-Mn-Zr-Cr alloy, wherein the alloy composition is: Mg: 4.0%, Mn: 1.0%, Zr: 0.2%, Cr: 0.1%, the balance being aluminum and unavoidable impurities, wherein the impurities are derived from raw materials, which are unavoidable, and the impurity content is: Fe: 0.3%, Si: 0.2%, Cu: 0.05%, Zn: 0.05%. After batching, the raw materials are heated to 780°C, completely melted, and then held for 40 min and stirred multiple times with a stone mill rod. Then, the temperature is lowered to 750°C for argon degassing for 3-5 min. After the melt is allowed to stand and the slag is removed, it is poured into a mold (steel mold, copper mold, graphite mold) preheated to 200°C at 730-750°C to obtain a cast ingot.

[0081] Step 2, pre-aging treatment of the as-cast Al-Mg-Mn-Zr-Cr alloy obtained in Step 1 at 300°C. The pre-aging treatment time is 8 h, and the alloy is air-cooled to room temperature.

[0082] Step 3, cold rolling of the alloy sheet obtained in Step 2 at room temperature, pass reduction of 2%, rolling speed of 0.1 m / s, and total reduction of 10%. -1

[0083] Step 4, aging treatment of the alloy obtained in Step 3 at 400°C for 12 h.

[0084] Step 5, hot rolling of the alloy obtained in Step 4 at a rolling temperature of 320°C, pass reduction of 10%, and total reduction of 70%.

[0085] The alloy obtained in Step 4 is subjected to room temperature tensile mechanical property testing. The tensile properties are shown in Table 1, with a final yield strength of 165.5±2.6 MPa, a tensile strength of 282.4±5.7 MPa, and an elongation of 6.4±1.3%. The alloy obtained in Step 5 is subjected to room temperature tensile mechanical property testing. The tensile properties are shown in Table 1, with a final yield strength of 281.8±2.5 MPa, a tensile strength of 375.7±8.7 MPa, and an elongation of 9.7±2.4%. The alloy obtained in Step 5 is subjected to 300°C high-temperature tensile mechanical property testing. The tensile properties are shown in Table 3, with a final yield strength of 91.3±3.7 MPa, a tensile strength of 91.3±3.7 MPa, and an elongation of 37.2±4.9%.

[0086] Table 1, comparison of room temperature tensile property testing of each example and comparative example.

[0087]

[0088]

[0089] ​Table 2. Statistical distribution of precipitated phases in corresponding states of each embodiment and comparative example.

[0090] Alloy State Equivalent radius / nm Number density / m -3 ]] Volume fraction / % Example 1 400℃ / 12h 40.2 6.4 x 10 20 ]] 17.5 Comparative Example 1 400℃ / 12h 50.6 3.3 x 10 20 ]]> 17.7 Comparative Example 2 400℃ / 12h 80.8 5.2 x 10 19 ]] 12.1

[0091] Table 3. Comparison of tensile properties at 300℃ for each embodiment and comparative example under corresponding conditions.

[0092]

[0093] As can be seen from Tables 1 and 3, compared with Comparative Example 4, Example 1 exhibits stronger heat resistance. This is mainly due to the multi-element synergistic microalloying of Zr, Cr, Mo, etc., which promotes the precipitation of high-density nanoscale α phase and Al3Zr dispersed particles, directly providing considerable strength. In the subsequent rolling and annealing process, its indirect strengthening effect of inhibiting recrystallization is still retained, thus greatly improving the strength of the final product.

[0094] from Figure 1 As can be seen, after pre-aging and pre-deformation treatment, the alloy of Example 1 exhibits significantly improved hardness and a significantly shorter time to reach peak hardness compared to the as-cast alloy of Comparative Example 2. Compared to the alloy of Comparative Example 1 which only underwent pre-deformation, the hardness at each aging stage is also improved. Furthermore, it can be observed that after prolonged high-temperature aging treatment, the hardness of the alloy of Example 1 remains at a high level. This indicates that the pre-aging and pre-deformation process can accelerate the aging response process of Al-Mg-Mn-Zr-Cr-Mo alloys, while further improving the dispersion strengthening effect and maintaining high heat resistance.

[0095] from Figures 2-4 As can be seen, after the pre-aging + pre-deformation treatment, the distribution of precipitates in the alloy is significantly refined and the quantity is significantly increased. In the two alloys that include the pre-deformation treatment, the precipitates are observed to be distributed along dislocation lines, indicating that the pre-deformation process can increase the nucleation sites of the α phase by introducing dislocations, thereby improving the dispersion strengthening effect of the alloy. As can be seen from Table 2, compared with Comparative Example 1 and Comparative Example 2, the precipitates in Example 1 have a significantly higher number density and smaller size, indicating that the pre-aging + pre-deformation treatment can effectively promote the precipitation of the α phase, which is consistent with... Figure 1 The hardness changes are consistent with those in the medium.

[0096] In summary, the application discloses a high-heat-resistance dispersion strengthening type Al-Mg-Mn-Zr-Cr-Mo alloy preparation and processing method, first, Zr, Cr, Mo multi-element synergistic micro-alloying is used to promote the precipitation of nanoscale alpha phase and Al3Zr dispersed particles, which is beneficial to improve 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 the peak strength, and can effectively improve the dispersion strengthening effect of the alloy, so that the mechanical properties are far superior to the current conventional Al-Mg-Mn alloy, and the application range of the Al-Mg-Mn alloy is expanded.

[0097] The above specific description further details the purpose, technical scheme and beneficial effects of the application, and it should be understood that the above description is only a specific embodiment of the application and is not used to limit the protection scope of the application, and any modification, equivalent replacement, improvement, etc. within the spirit and principle of the application should be included in the protection scope of the application.

Claims

1. A method for preparing a highly heat-resistant dispersion-strengthened Al-Mg-Mn-Zr-Cr-Mo alloy, characterized in that: The raw materials are mixed according to the component ratio; the mixed raw materials are heated and melted and then cast to obtain an ingot; the alloy of the ingot is subjected to high-temperature pre-aging treatment and then cooled; the pre-aged sample is pre-deformed, then subjected to artificial aging hardening treatment, and finally subjected to hot rolling treatment to obtain a rolled plate. Ingredients by weight 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%, balance being aluminum and unavoidable impurities; Impurities originate from the raw materials and are unavoidable. The impurity content is as follows: Si: 0.1-0.5%, Fe: 0.1-0.5%, Cu≤0.05%, Zn≤0.05%. The method for high-temperature pre-aging treatment is as follows: place the cast alloy at a temperature of 200~300 ℃ and hold for 0.5~36 h, then air cool or quench to room temperature; The pre-deformation process is room temperature cold rolling deformation, with a reduction per pass of 1-3% and a total reduction of 5-15%; or the pre-deformation process is room temperature pre-stretching, with a strain rate of 1×10⁻⁶. -3 s -1 The dependent variable is 2-6%; The artificial aging hardening treatment is carried out at a temperature of 400~425 ℃ for a time of 4~24 h; The hot rolling temperature is 280~320 ℃, the reduction per pass is 5~10%, and the total reduction is 65%~75%.

2. The method as described in claim 1, characterized in that: The heating and melting method is as follows: the mixed raw materials are heated to 850-900 ℃, melted and held at the temperature for 30-50 min, cooled to 740-760 ℃ for argon degassing, and the resulting melt is allowed to stand and slag is removed before being poured into a mold preheated to 200-250 ℃ at 730-750 ℃ ​​to obtain an ingot.

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