Heat-resistant high-strength weldable rare earth aluminum alloy and preparation method thereof

Abstract

The invention provides a heat-resistant high-strength weldable rare earth aluminum alloy. The heat-resistant high-strength weldable rare earth aluminum alloy comprises 0-0.1 wt% of silicon; 0 to 0.2 wt% of iron; 5.5 wt% to 7.1 wt% of magnesium; 0.7 wt% to 1.2 wt% of manganese; 0.05 wt% to 0.15 wt% of zirconium; 0.05 wt% to 0.18 wt% of scandium; 1.2 wt% to 2.0 wt% of zinc; 0.03 wt% to 0.07 wt% of titanium; 0.04 wt% to 0.09 wt% of nickel; the balance is Al; wherein the total amount of impurities is less than or equal to 0.15%. The invention further provides a preparation method of the heat-resistant high-strength weldable rare earth aluminum alloy. The prepared heat-resistant high-strength weldable rare earth aluminum alloy has good room temperature strength, weldability and high temperature resistance, and can be used in the fields of aviation, aerospace crafts and the like.

Description

Technical Field

[0001] The invention relates to the technical field of aluminum alloy materials, and in particular to a heat-resistant, high-strength, weldable rare earth aluminum alloy and a preparation method thereof. Background Art

[0002] At present, the widely used heat-resistant materials are mainly steel, titanium alloy, metal-based composite materials, nickel-based high-temperature alloys, etc. These materials have high density, high cost, and difficult processing, and it is difficult to meet the lightweight and low-cost requirements in the fields of aviation and aerospace. Heat-resistant aluminum alloys have the advantages of low density, high strength, corrosion resistance, and low price, and are lightweight alloy materials with great potential. Heat-resistant aluminum alloys represented by the Al-Cu system mainly obtain good strength and heat resistance by precipitating stable heat-resistant strengthening phases through aging heat treatment. Its room temperature strength can reach more than 420MPa, but when the temperature is higher than 300℃, the strengthening phase will be significantly coarsened or dissolved, resulting in a serious decline in mechanical properties, and Al-Cu alloys are difficult to weld, which limits their application range. Therefore, it is extremely urgent to develop new high-strength, heat-resistant and weldable aluminum alloys.

[0003] At present, the research on high-strength heat-resistant aluminum alloys mainly focuses on improving the stability of the precipitated phase to improve the heat resistance of the alloy, such as by adding silver, scandium, manganese, vanadium, erbium, nickel, gadolinium, neodymium, and composite additions of scandium + iron + silicon, iron + nickel, iron + vanadium, etc., or by adding Al2O3, which is stable at high temperatures. 2 O 3 、SiC、TiC、TiB 2 However, although the above method can improve the heat resistance of the alloy, the corresponding alloy structure control process is complicated and difficult to be widely used, and it further increases the difficulty of welding and reduces the application performance of high-strength heat-resistant aluminum alloy. Summary of the invention

[0004] In view of this, the present invention provides a heat-resistant, high-strength, weldable rare earth aluminum alloy and a preparation method thereof. The heat-resistant, high-strength, weldable rare earth aluminum alloy provided in the present application has the advantages of high room temperature strength, low rare earth dosage, good weldability and good heat resistance.

[0005] The present application provides a heat-resistant, high-strength, weldable rare earth aluminum alloy, comprising:

[0006] 0~0.1wt% silicon;

[0007] 0~0.2wt% iron;

[0008] 5.5 wt% to 7.1 wt% magnesium;

[0009] 0.7 wt% to 1.2 wt% manganese;

[0010] 0.05 wt%~0.15 wt% zirconium;

[0011] 0.05 wt%~0.18 wt% scandium;

[0012] 1.2 wt%~2.0 wt% zinc;

[0013] 0.03 wt%~0.07 wt% titanium;

[0014] 0.04 wt%~0.09 wt% nickel;

[0015] The balance is Al;

[0016] Among them, the total amount of impurities is ≤0.15%.

[0017] In some specific implementations, the heat-resistant, high-strength, weldable rare earth aluminum alloy includes:

[0018] 0~0.1wt% silicon;

[0019] 0~0.2wt% iron;

[0020] 5.6 wt% to 6.8 wt% magnesium;

[0021] 0.7 wt% to 1.2 wt% manganese;

[0022] 0.08 wt% to 0.12 wt% zirconium;

[0023] 0.07 wt%~0.16 wt% scandium;

[0024] 1.25 wt% to 1.8 wt% zinc;

[0025] 0.04 wt% to 0.06 wt% titanium;

[0026] 0.045 wt% to 0.09 wt% nickel;

[0027] The balance is Al;

[0028] Among them, the total amount of impurities is ≤0.15%.

[0029] In some specific implementations, the heat-resistant, high-strength, weldable rare earth aluminum alloy includes:

[0030] 0~0.1wt% silicon;

[0031] 0~0.2wt% iron;

[0032] 5.7 wt% to 6.6 wt% magnesium;

[0033] 0.7 wt% to 1.2 wt% manganese;

[0034] 0.09 wt% to 0.12 wt% zirconium;

[0035] 0.09 wt%~0.12wt% scandium;

[0036] 1.25 wt% to 1.7 wt% zinc;

[0037] 0.04 wt% to 0.06 wt% titanium;

[0038] 0.045 wt% to 0.09 wt% nickel;

[0039] The balance is Al;

[0040] Among them, the total amount of impurities is ≤0.15%.

[0041] The present application also provides a method for preparing the heat-resistant, high-strength, weldable rare earth aluminum alloy described in the above technical solution, comprising the following steps:

[0042] (1) Preparing ingredients according to the formula, melting, refining and casting to obtain aluminum alloy ingots;

[0043] (2) homogenizing the aluminum alloy ingot;

[0044] (3) hot rolling and cold rolling the aluminum alloy ingot after the homogenization treatment in sequence to obtain an aluminum alloy slab;

[0045] (4) The aluminum alloy slab is subjected to a stabilization annealing treatment.

[0046] In some specific implementations, step (2) includes:

[0047] The aluminum alloy ingot billet is heated to 270°C~280°C, kept warm for 10 hours~14 hours, then heated to 410°C~430°C, kept warm for 10 hours~14 hours, and finally heated to 450°C~470°C, kept warm for 5 hours~7 hours, and cooled.

[0048] In some specific implementations, in step (2), the cooling is strong wind cooling.

[0049] In some specific implementations, in step (3), the hot rolling temperature is 450° C. to 470° C., and the hot rolling reduction is 65% to 75%.

[0050] In some specific implementations, in step (3), the cold rolling temperature is room temperature, and the cold rolling reduction is 65% to 75%.

[0051] In some specific implementations, in step (3), after hot rolling and before cold rolling, the following steps are further included:

[0052] The hot rolled slab is intermediate annealed.

[0053] In some specific implementations, in step (4), the temperature of the stabilization annealing treatment is 160° C. to 200° C., and the time is 3 hours to 5 hours.

[0054] The heat-resistant, high-strength, weldable rare earth aluminum alloy provided in the present application includes: 0~0.1wt% silicon; 0~0.2wt% iron; 5.5wt%~7.1wt% magnesium; 0.7wt%~1.2wt% manganese; 0.05wt%~0.15wt% zirconium; 0.05wt%~0.18wt% scandium; 1.2wt%~2.0wt% zinc; 0.03wt%~0.07wt% titanium; 0.04wt%~0.09wt% nickel; the balance is Al; wherein the total amount of impurities is ≤0.15%. The present application increases the content of magnesium and zinc elements, matches the low-temperature stabilization treatment, obtains a mixed grain structure of cold rolling deformation and partial recovery, and precipitates a precipitated phase T phase with good thermal stability. Due to the combined effect of work hardening, substructure strengthening and precipitation strengthening, the room temperature tensile strength of the rare earth aluminum alloy plate reaches 450~480MPa, the yield strength is ≥400MPa, and the elongation is ≥15.0%; by adding trace rare earth scandium and zirconium in combination with a three-stage homogenization treatment, the role of rare earth scandium and zirconium is fully utilized, and at the same time, the content of conventional elements such as manganese, titanium, and nickel with lower prices is increased, thereby forming an Al alloy core-shell structure containing rare earth elements. 3 (Sc, Zr) phase and short rod-shaped Al 6 Mn phase, massive Al 3 Ti phase, Al 3 The multiphase coexistence of Ni phase and Al (Mn, Ni, Fe) phase reduces the amount of rare earth elements and the preparation cost while ensuring the performance; the Al 3 (Sc, Zr) phase, Al 6 Mn phase, Al 3 Ti phase, Al 3 The Ni phase and Al (Mn, Ni, Fe) phase are relatively stable at high temperatures, which can inhibit the performance degradation caused by recrystallization softening caused by welding heat input and thermal effects. 3 (Sc, Zr) phase, Al 6 Mn phase, Al 3 Ti phase, Al 3The dispersion strengthening of Ni phase and Al (Mn, Ni, Fe) phase and the precipitation strengthening of high temperature stable T phase reinforce the performance, so that the rare earth aluminum alloy plate MIG (molten inert gas shielded welding) welding coefficient is ≥ 0.65, and after exposure to 300 ° C for 100 hours, there is still 75-85% of the performance, and after exposure to 350 ° C for 100 hours, there is still 55-65% of the performance. The experimental results show that the heat-resistant, high-strength, weldable rare earth aluminum alloy prepared in this application has good room temperature strength, weldability and high temperature resistance, and can be used in aviation, aerospace vehicles and other fields. DETAILED DESCRIPTION

[0055] It should be understood that the expression "one or more of..." includes each of the items recited after the expression individually and in various different combinations of two or more of the recited items, unless otherwise understood from the context and usage. The expression "and / or" in combination with three or more recited items should be understood to have the same meaning, unless otherwise understood from the context.

[0056] The use of the terms "comprising", "having" or "containing", including their grammatical synonyms, should generally be understood as open and non-restrictive, for example not excluding other unrecited elements or steps, unless otherwise specifically stated or otherwise understood from the context.

[0057] It should be understood that the order of steps or the order in which certain actions are performed is not important as long as the present invention remains operable. In addition, two or more steps or actions may be performed simultaneously.

[0058] The use of any and all examples or exemplary language, such as "for example" or "including", herein is intended only to better illustrate the invention and does not limit the scope of the invention unless otherwise claimed. No language in this specification should be construed as indicating that any non-claimed element is essential to the practice of the invention.

[0059] In addition, the numerical ranges and parameters used to define the present invention are approximate values, and the relevant values ​​in the specific embodiments have been presented as accurately as possible. However, any numerical value inherently inevitably contains standard deviations due to individual test methods. Therefore, unless otherwise expressly stated, it should be understood that all ranges, quantities, values ​​and percentages used in this disclosure are modified by "about". Here, "about" generally means that the actual value is within plus or minus 10%, 5%, 1% or 0.5% of a specific value or range.

[0060] The present application provides a heat-resistant, high-strength, weldable rare earth aluminum alloy, comprising:

[0061] 0~0.1wt% silicon;

[0062] 0~0.2wt% iron;

[0063] 5.5 wt% to 7.1 wt% magnesium;

[0064] 0.7 wt% to 1.2 wt% manganese;

[0065] 0.05 wt%~0.15 wt% zirconium;

[0066] 0.05 wt%~0.18 wt% scandium;

[0067] 1.2 wt%~2.0 wt% zinc;

[0068] 0.03 wt%~0.07 wt% titanium;

[0069] 0.04 wt%~0.09 wt% nickel;

[0070] The balance is Al;

[0071] Among them, the total amount of impurities is ≤0.15%.

[0072] The heat-resistant, high-strength, weldable rare earth aluminum alloy provided in the present application includes 0-0.1wt% silicon, and the silicon content is preferably 0.0001wt%-0.09wt%, and more preferably 0.001wt%-0.08wt%.

[0073] The heat-resistant, high-strength, weldable rare earth aluminum alloy provided in the present application includes 0-0.2wt% of iron, and Fe can form Al(Mn,Ni,Fe) phase with Al, Mn, Ni, etc., thereby reducing the amount of rare earth while ensuring the performance. In some specific implementations, the content of Fe is preferably 0.0001wt%-0.19wt%, and more preferably 0.001wt%-0.18wt%.

[0074] The heat-resistant, high-strength, weldable rare earth aluminum alloy provided in the present application includes 5.5wt% to 7.1wt% of magnesium. The present application increases the content of magnesium and zinc elements, obtains a mixed grain structure of cold rolling deformation and partial recovery, and precipitates a precipitated phase T phase with good thermal stability, and combines the combined effects of work hardening, substructure strengthening and precipitation strengthening to improve the room temperature strength of the rare earth aluminum alloy sheet. In some specific implementations, the content of Mg is preferably 5.6wt% to 6.8wt%, and more preferably 5.7wt% to 6.6wt%.

[0075] The heat-resistant, high-strength, weldable rare earth aluminum alloy provided in the present application includes 0.7wt% to 1.2wt% manganese, which can form short rod-shaped Al with Al. 6Mn phase, while forming Al(Mn,Ni,Fe) phase with Al, Ni, Fe, etc., can improve the performance of aluminum alloy, and reduce the amount of rare earth while ensuring the performance. In some specific implementations, the content of Mn is preferably 0.72wt%~1.19wt%, more preferably 0.75wt%~1.15wt%.

[0076] The heat-resistant, high-strength, weldable rare earth aluminum alloy provided in the present application includes 0.05 wt% to 0.15 wt% zirconium, and Zr, Sc and Al can form an Al core-shell structure containing rare earth elements. 3 (Sc, Zr) phase improves the heat resistance of the aluminum alloy. In some specific implementations, the Zr content is preferably 0.08wt%~0.12wt%, more preferably 0.09wt%~0.12wt%.

[0077] The heat-resistant, high-strength, weldable rare earth aluminum alloy provided in the present application includes 0.05 wt% to 0.18 wt% of scandium, and Sc, Zr and Al can form an Al core-shell structure containing rare earth elements. 3 (Sc, Zr) phase improves the heat resistance of the aluminum alloy. In some specific implementations, the Sc content is preferably 0.07wt%~0.16wt%, more preferably 0.09wt%~0.12wt%.

[0078] The heat-resistant, high-strength, weldable rare earth aluminum alloy provided in the present application includes 1.2 wt% to 2.0 wt% of zinc. The present application increases the content of zinc so that the zinc element combines with the magnesium element to precipitate a precipitate phase T phase with good thermal stability, which plays a role of precipitation strengthening, thereby improving the room temperature strength and heat resistance of the rare earth aluminum alloy sheet. In some specific implementations, the content of Zn is preferably 1.25wt% to 1.8wt%, and more preferably 1.25wt% to 1.7wt%.

[0079] The heat-resistant, high-strength, weldable rare earth aluminum alloy provided in the present application includes 0.03 wt% to 0.07 wt% titanium, and Ti can form a blocky Al alloy with Al. 3 Ti phase improves the performance of aluminum alloy and reduces the amount of rare earth while ensuring the performance. In some specific implementations, the content of Ti is preferably 0.035wt%~0.065wt%, more preferably 0.04wt%~0.06wt%.

[0080] The heat-resistant, high-strength, weldable rare earth aluminum alloy provided in the present application includes 0.04 wt% to 0.09 wt% nickel, and Ni can form Al with Al. 3Ni phase, and at the same time form Al(Mn,Ni,Fe) phase with Al, Mn, Fe, etc., to improve the performance of aluminum alloy, and reduce the amount of rare earth while ensuring the performance. In some specific implementations, the content of Ni is preferably 0.045wt%~0.09wt%, more preferably 0.05wt%~0.09wt%.

[0081] The balance of the heat-resistant, high-strength and weldable rare earth aluminum alloy provided by the present application is Al, wherein the total amount of impurities is ≤0.15%.

[0082] In some specific implementations, the heat-resistant, high-strength, weldable rare earth aluminum alloy includes:

[0083] 0~0.1wt% silicon;

[0084] 0~0.2wt% iron;

[0085] 5.6 wt% to 6.8 wt% magnesium;

[0086] 0.7 wt% to 1.2 wt% manganese;

[0087] 0.08 wt% to 0.12 wt% zirconium;

[0088] 0.07 wt%~0.16 wt% scandium;

[0089] 1.25 wt% to 1.8 wt% zinc;

[0090] 0.04 wt% to 0.06 wt% titanium;

[0091] 0.045 wt% to 0.09 wt% nickel;

[0092] The balance is Al;

[0093] Among them, the total amount of impurities is ≤0.15%.

[0094] In some specific implementations, the heat-resistant, high-strength, weldable rare earth aluminum alloy includes:

[0095] 0~0.1wt% silicon;

[0096] 0~0.2wt% iron;

[0097] 5.7 wt% to 6.6 wt% magnesium;

[0098] 0.7 wt% to 1.2 wt% manganese;

[0099] 0.09 wt% to 0.12 wt% zirconium;

[0100] 0.09 wt%~0.12wt% scandium;

[0101] 1.25 wt% to 1.7 wt% zinc;

[0102] 0.04 wt% to 0.06 wt% titanium;

[0103] 0.045 wt% to 0.09 wt% nickel;

[0104] The balance is Al;

[0105] Among them, the total amount of impurities is ≤0.15%.

[0106] In some specific implementations, the heat-resistant, high-strength, weldable rare earth aluminum alloy includes:

[0107] 0~0.1wt% silicon;

[0108] 0~0.2wt% iron;

[0109] 5.8 wt% to 6.8 wt% magnesium;

[0110] 0.9 wt% to 1.2 wt% manganese;

[0111] 0.08 wt% to 0.12 wt% zirconium;

[0112] 0.07 wt%~0.16 wt% scandium;

[0113] 1.4 wt% to 1.8 wt% zinc;

[0114] 0.04 wt% to 0.06 wt% titanium;

[0115] 0.045 wt% to 0.09 wt% nickel;

[0116] The balance is Al;

[0117] Among them, the total amount of impurities is ≤0.15%.

[0118] In some specific implementations, the heat-resistant, high-strength, weldable rare earth aluminum alloy includes:

[0119] 0~0.1wt% silicon;

[0120] 0~0.2wt% iron;

[0121] 6.2 wt% to 6.6 wt% magnesium;

[0122] 1.0 wt% to 1.2 wt% manganese;

[0123] 0.10 wt% to 0.12 wt% zirconium;

[0124] 0.09 wt%~0.12wt% scandium;

[0125] 1.5 wt% to 1.7 wt% zinc;

[0126] 0.05 wt%~0.06 wt% titanium;

[0127] 0.045 wt% to 0.09 wt% nickel;

[0128] The balance is Al;

[0129] Among them, the total amount of impurities is ≤0.15%.

[0130] The present application also provides a method for preparing the heat-resistant, high-strength, weldable rare earth aluminum alloy described in the above technical solution, comprising the following steps:

[0131] (1) Preparing ingredients according to the formula, melting, refining and casting to obtain aluminum alloy ingots;

[0132] (2) homogenizing the aluminum alloy ingot;

[0133] (3) hot rolling and cold rolling the aluminum alloy ingot after the homogenization treatment in sequence to obtain an aluminum alloy slab;

[0134] (4) The aluminum alloy slab is subjected to a stabilization annealing treatment.

[0135] The present application first prepares the ingredients according to the aluminum alloy composition designed above. The present application has no special restrictions on the raw materials of the components, which can be pure metal ingots or intermediate alloys, such as aluminum-manganese, aluminum-zirconium, aluminum-scandium, aluminum-nickel and other intermediate alloys. Specifically, the present application first heats and melts the pure aluminum ingot, and then adds magnesium ingots, zinc ingots, aluminum-manganese, aluminum-zirconium, aluminum-scandium, aluminum-nickel and other intermediate alloys to continue melting to obtain molten metal. After obtaining the molten metal, it is refined, allowed to stand, degassed, and filtered, and then an aluminum-titanium-boron grain refiner is added online to cast it into an aluminum alloy ingot containing rare earth scandium. The present application has no special restrictions on the specific processes of melting, refining, standing, degassing, filtering and casting, and the operations familiar to those skilled in the art can be used.

[0136] After obtaining the aluminum alloy ingot, it is preferred to perform homogenization treatment after removing surface defects such as pores and segregation layers by milling. The present application preferably performs three-stage homogenization treatment, and the present application preferably performs three-stage homogenization treatment in an air circulation furnace. Specifically, the homogenization treatment includes:

[0137] The aluminum alloy ingot billet is heated to 270°C~280°C, kept warm for 10 hours~14 hours, then heated to 410°C~430°C, kept warm for 10 hours~14 hours, and finally heated to 450°C~470°C, kept warm for 5 hours~7 hours, and cooled.

[0138] The present application has no special restrictions on the heating rate of the homogenization treatment. When an air circulation furnace is used for the homogenization treatment, the heating rate can be controlled by the furnace temperature. In some specific implementations, in the step (2), the cooling is strong wind cooling.

[0139] After the aluminum alloy ingot is homogenized, the present application performs hot rolling and cold rolling on it in sequence. Specifically, the present application first heats the aluminum alloy ingot after homogenization to the hot rolling temperature, keeps it warm and then takes it out of the furnace for hot rolling. In some specific implementations, the hot rolling temperature is 450°C~470°C, and the hot rolling reduction is 65%~75%. After the hot rolling is completed, it is preferred to perform intermediate annealing on the hot-rolled slab, and the temperature of the intermediate annealing is preferably 450°C~470°C, and the time is preferably not less than 20 minutes. In fact, the hot-rolled slab can be put back into an air circulation furnace for annealing for not less than 20 minutes. After the above-mentioned slab is completely cooled to room temperature, it is cold rolled with a cold rolling reduction of 65~75%.

[0140] After the cold-rolled sheet is obtained, it is subjected to a stabilization annealing treatment. In some specific implementations, in the step (4), the annealing treatment is performed at a temperature of 160°C to 200°C and for a time of 3 hours to 5 hours.

[0141] The present invention increases the content of magnesium and zinc elements and matches the low-temperature stabilization treatment to obtain a mixed grain structure of cold rolling deformation and partial recovery and a precipitation phase T phase with good thermal stability. Due to the combined effect of work hardening, substructure strengthening and precipitation strengthening, the room temperature tensile strength of the rare earth aluminum alloy plate reaches 450~480MPa, the yield strength is ≥400MPa, and the elongation is ≥15.0%; at the same time, the present invention adds trace amounts of rare earth scandium and zirconium in combination with a three-stage homogenization treatment to give full play to the role of rare earth scandium and zirconium, while increasing the content of conventional elements such as manganese, titanium, and nickel, thereby forming an Al alloy core-shell structure containing rare earth elements. 3 (Sc, Zr) phase and short rod-shaped Al 6 Mn phase, massive Al 3 Ti phase, Al 3 The multiphase coexistence of Ni phase and Al (Mn, Ni, Fe) phase reduces the amount of rare earth elements and the preparation cost while ensuring the performance; the Al 3 (Sc, Zr) phase, Al 6 Mn phase, Al 3 Ti phase, Al3 The Ni phase and Al (Mn, Ni, Fe) phase are relatively stable at high temperatures, which can inhibit the performance degradation caused by recrystallization softening caused by welding heat input and thermal effects. 3 (Sc, Zr) phase, Al 6 Mn phase, Al 3 Ti phase, Al 3 The dispersion strengthening of the Ni phase and the Al (Mn, Ni, Fe) phase and the precipitation strengthening of the high-temperature stable T phase reinforce the performance, so that the rare earth aluminum alloy plate MIG (molten inert gas shielded welding) welding coefficient is ≥0.65, and the performance is still 75~85% after exposure at 300°C for 100 hours, and the performance is still 55~65% after exposure at 350°C for 100 hours.

[0142] The heat-resistant, high-strength, weldable rare earth aluminum alloy and its preparation method provided by the present application are further described below in conjunction with embodiments.

[0143] Example 1

[0144] A heat-resistant, high-strength, weldable rare earth aluminum alloy plate comprises the following chemical components in percentage by mass: 0.05% silicon, 0.12% iron, 5.7% magnesium, 0.76% manganese, 0.11% zirconium, 0.17% scandium, 1.33% zinc, 0.04% titanium, 0.045% nickel, and the remainder is Al.

[0145] The production method of the heat-resistant, high-strength, weldable rare earth aluminum alloy plate comprises the following steps:

[0146] (1) The aluminum alloy components are prepared in the above-designed mass percentages, pure aluminum ingots are added to a smelting furnace for heating and melting, and then magnesium ingots, zinc ingots, and aluminum-manganese, aluminum-zirconium, aluminum-scandium, and aluminum-nickel master alloys are added. After the molten metal is refined, allowed to stand, degassed, and filtered, an aluminum-titanium-boron grain refiner is added online and cast into an aluminum alloy ingot containing rare earth scandium. The surface defects such as pores and segregation layers are removed by milling to obtain an aluminum alloy ingot blank.

[0147] (2) The aluminum alloy ingot prepared as above is placed in an air circulation furnace for three-stage homogenization treatment. The heating rate is controlled by furnace temperature. The specific process is: the aluminum alloy ingot is heated to 275°C with the furnace, kept warm for 12 hours, then heated to 420°C, kept warm for 12 hours, and finally heated to 460°C, kept warm for 6 hours, and cooled by strong wind.

[0148] (3) The aluminum alloy ingots subjected to the homogenization treatment in (2) are heated in an air circulation furnace to a hot rolling temperature of 450°C for 4 hours, and then taken out of the furnace for hot rolling with a hot rolling reduction of 68.0%. After the hot rolling is completed, the hot rolled slabs are put back into the air circulation furnace for annealing for 30 minutes. After the slabs are completely cooled to room temperature, they are cold rolled with a cold rolling reduction of 70.1%.

[0149] (4) The slabs deformed by hot rolling and cold rolling in (3) are subjected to stabilization annealing in an air circulation furnace at a temperature of 180°C for 4 hours.

[0150] After tensile tests at room temperature and after MIG welding, the rare earth aluminum alloy sheet has a tensile strength of 473MPa, a yield strength of 418MPa, an elongation of 18.0%, and a MIG welding coefficient of 0.72. After exposure at 300°C for 100 hours, the tensile strength is 387MPa, the yield strength is 343MPa, and the elongation is 27.5%; after exposure at 350°C for 100 hours, the tensile strength is 297MPa, the yield strength is 265MPa, and the elongation is 31.0%.

[0151] Example 2

[0152] The production and preparation method of Example 2 is substantially the same as that of Example 1, except that the mass percentage of the chemical components of the high-strength and heat-resistant rare earth aluminum alloy is as follows: silicon 0.06%, iron 0.15%, magnesium 6.0%, manganese 0.98%, zirconium 0.099%, scandium 0.096%, zinc 1.35%, titanium 0.057%, nickel 0.061%, and the balance is Al. The difference from Example 1 is that the mass percentage of scandium in the high-strength and heat-resistant rare earth aluminum alloy of Example 2 is reduced to 0.096%, the mass percentage of manganese is increased to 0.98%, the mass percentage of zinc is increased to 1.56%, the mass percentage of titanium is increased to 0.057%, and the mass percentage of nickel is increased to 0.061%.

[0153] After tensile tests at room temperature and after MIG welding, the rare earth aluminum alloy sheet has a tensile strength of 458MPa, a yield strength of 405MPa, an elongation of 18.5%, and a MIG welding coefficient of 0.70. After exposure at 300℃ for 100 hours, the tensile strength is 381MPa, the yield strength is 332MPa, and the elongation is 27.0%; after exposure at 350℃ for 100 hours, the tensile strength is 284MPa, the yield strength is 254MPa, and the elongation is 31.0%.

[0154] Example 3

[0155] The production and preparation method of Example 3 is substantially the same as that of Example 1, except that the mass percentage of the chemical composition of the high-strength and heat-resistant rare earth aluminum alloy is as follows: silicon 0.05%, iron 0.18%, magnesium 5.9%, manganese 1.13%, zirconium 0.10%, scandium 0.054%, zinc 1.29%, titanium 0.068%, nickel 0.087%, and the balance is Al. The difference from Example 1 is that the mass percentage of scandium in the high-strength and heat-resistant rare earth aluminum alloy of Example 3 is reduced to 0.047%, the mass percentage of manganese is increased to 1.13%, the mass percentage of zinc is increased to 1.89%, the mass percentage of titanium is increased to 0.068%, and the mass percentage of nickel is increased to 0.087%.

[0156] After tensile tests at room temperature and after MIG welding, the rare earth aluminum alloy sheet has a tensile strength of 464MPa, a yield strength of 411MPa, an elongation of 17.5%, and a MIG welding coefficient of 0.68. After exposure at 300°C for 100 hours, the tensile strength is 362MPa, the yield strength is 326MPa, and the elongation is 28.5%; after exposure at 350°C for 100 hours, the tensile strength is 271MPa, the yield strength is 242MPa, and the elongation is 34.0%.

[0157] Example 4

[0158] The production and preparation method of Example 4 is substantially the same as that of Example 1, except that the mass percentage of chemical components of the high-strength and heat-resistant rare earth aluminum alloy is as follows: silicon 0.055%, iron 0.15%, magnesium 6.9%, manganese 0.78%, zirconium 0.10%, scandium 0.16%, zinc 1.63%, titanium 0.05%, nickel 0.048%, and the balance is Al. The difference from Example 1 is that the mass percentage of magnesium in the high-strength and heat-resistant rare earth aluminum alloy of Example 4 is increased to 6.9%, and the mass percentage of zinc is increased to 1.63%.

[0159] After tensile tests at room temperature and after MIG welding, the rare earth aluminum alloy sheet has a tensile strength of 469MPa, a yield strength of 425MPa, an elongation of 16.0%, and a MIG welding coefficient of 0.66. After exposure at 300°C for 100 hours, the tensile strength is 367MPa, the yield strength is 324MPa, and the elongation is 25.5%; after exposure at 350°C for 100 hours, the tensile strength is 266MPa, the yield strength is 241MPa, and the elongation is 31.5%.

[0160] Example 5

[0161] The alloy composition of Example 5 is substantially the same as that of Example 1, except that in step (4), the slab after hot rolling and cold rolling is subjected to stabilization annealing in an air circulation furnace at a temperature of 200° C. for 4 hours. Compared with Example 1, the temperature of the stabilization annealing is increased to 200° C.

[0162] After room temperature tensile testing and MIG welding tensile testing, the rare earth aluminum alloy sheet has a tensile strength of 451MPa, a yield strength of 402MPa, an elongation of 19.5%, and a MIG welding coefficient of 0.71. After exposure at 300°C for 100 hours, the tensile strength is 375MPa, the yield strength is 334MPa, and the elongation is 28.5%; after exposure at 350°C for 100 hours, the tensile strength is 282MPa, the yield strength is 255MPa, and the elongation is 31.0%.

[0163] Comparative Example 1

[0164] The production and preparation methods of Comparative Example 1 and Example 3 are substantially the same, except that the mass percentages of the chemical components of the high-strength and heat-resistant rare earth aluminum alloy are as follows: silicon 0.05%, iron 0.15%, magnesium 5.7%, manganese 0.001%, zirconium 0.11%, scandium 0.055%, zinc 1.30%, titanium 0.066%, nickel 0.071%, and the balance is Al. The difference from Example 3 is that the mass percentage of manganese in the high-strength and heat-resistant rare earth aluminum alloy of Comparative Example 1 is reduced to 0.001%.

[0165] After tensile tests at room temperature and after MIG welding, the tensile strength of the aluminum alloy plate is 438MPa, the yield strength is 398MPa, the elongation after fracture is 18.5%, and the MIG welding coefficient is 0.63. After exposure at 300℃ for 100 hours, the tensile strength is 297MPa, the yield strength is 273MPa, and the elongation after fracture is 28.0%; after exposure at 350℃ for 100 hours, the tensile strength is 229MPa, the yield strength is 207MPa, and the elongation after fracture is 35.5%; it can be seen that after heat exposure at 300℃, the performance of the plate described in Comparative Example 1 is only 68% of that at room temperature, and the performance after heat exposure at 350℃ is only about 52% of that at room temperature, and the performance decay is obvious.

[0166] Comparative Example 2

[0167] The production and preparation methods of Comparative Example 2 and Example 3 are substantially the same, except that the mass percentages of the chemical components of the high-strength and heat-resistant rare earth aluminum alloy are as follows: silicon 0.07%, iron 0.14%, magnesium 6.2%, manganese 0.001%, zirconium 0.095%, scandium 0.056%, zinc 1.25%, titanium 0.01%, nickel 0.085%, and the balance is Al. The difference from Example 3 is that the mass percentage of manganese in the high-strength and heat-resistant rare earth aluminum alloy of Comparative Example 2 is reduced to 0.001%, and the mass percentage of titanium is reduced to 0.01%.

[0168] After tensile tests at room temperature and after MIG welding, the tensile strength of the aluminum alloy plate is 435MPa, the yield strength is 378MPa, the elongation after fracture is 19.5%, and the MIG welding coefficient is 0.61. After exposure at 300℃ for 100 hours, the tensile strength is 287MPa, the yield strength is 250MPa, and the elongation after fracture is 29.0%; after exposure at 350℃ for 100 hours, the tensile strength is 218MPa, the yield strength is 187MPa, and the elongation after fracture is 37.5%; it can be seen that the performance of the plate described in Comparative Example 2 after heat exposure at 300℃ is only about 66% of that at room temperature, and the performance after heat exposure at 350℃ is only about 50% of that at room temperature, and the performance decay is obvious.

[0169] Comparative Example 3

[0170] The production and preparation method of Comparative Example 3 is substantially the same as that of Example 3, except that the mass percentage of the chemical composition of the high-strength and heat-resistant rare earth aluminum alloy is as follows: silicon 0.05%, iron 0.13%, magnesium 6.0%, manganese 0.01%, zirconium 0.099%, scandium 0.055%, zinc 1.25%, titanium 0.02%, nickel 0.001%, and the balance is Al. The difference from Example 3 is that the mass percentage of manganese in the high-strength and heat-resistant rare earth aluminum alloy of Comparative Example 3 is reduced to 0.01%, the mass percentage of titanium is reduced to 0.02%, and the mass percentage of nickel is reduced to 0.001%, that is, when the addition amount of the rare earth scandium element is only 0.055%, the contents of elements such as manganese, titanium, and nickel are not increased.

[0171] After tensile tests at room temperature and after MIG welding, the tensile strength of the aluminum alloy plate is 422MPa, the yield strength is 365MPa, the elongation after fracture is 19.5%, and the MIG welding coefficient is 0.58. After exposure at 300℃ for 100 hours, the tensile strength is 239MPa, the yield strength is 209MPa, and the elongation after fracture is 29.5%; after exposure at 350℃ for 100 hours, the tensile strength is 187MPa, the yield strength is 159MPa, and the elongation after fracture is 37.5%; it can be seen that the performance of the plate described in Comparative Example 3 after heat exposure at 300℃ is only 57% of that at room temperature, and the performance after heat exposure at 350℃ is only about 44% of that at room temperature, and the performance decay is obvious.

[0172] Comparative Example 4

[0173] The production and preparation method of Comparative Example 4 is substantially the same as that of Example 3, except that the mass percentage of the chemical composition of the high-strength and heat-resistant rare earth aluminum alloy is as follows: silicon 0.057%, iron 0.14%, magnesium 6.1%, manganese 1.11%, zirconium 0.11%, scandium 0.06%, zinc 0.001%, titanium 0.065%, nickel 0.085%, and the balance is Al. The difference from Example 3 is that the mass percentage of zinc in the high-strength and heat-resistant rare earth aluminum alloy of Comparative Example 4 is reduced to 0.001%.

[0174] After tensile tests at room temperature and after MIG welding, the tensile strength of the aluminum alloy plate is 440MPa, the yield strength is 385MPa, the elongation after fracture is 19.5%, and the MIG welding coefficient is 0.61. After exposure at 300℃ for 100 hours, the tensile strength is 305MPa, the yield strength is 271MPa, and the elongation after fracture is 28.5%; after exposure at 350℃ for 100 hours, the tensile strength is 221MPa, the yield strength is 193MPa, and the elongation after fracture is 37.0%; it can be seen that the performance of the plate described in Comparative Example 4 after heat exposure at 300℃ is only about 70% of that at room temperature, and the performance after heat exposure at 350℃ is only about 50% of that at room temperature, and the performance decay is obvious.

[0175] Comparative Example 5

[0176] The alloy composition of Comparative Example 5 is substantially the same as that of Example 3, except that in step (2), the first stage of homogenization treatment is 420°C for 12 hours, and the second stage is 460°C for 6 hours. Compared with Example 3, the homogenization is a two-stage treatment.

[0177] After tensile tests at room temperature and after MIG welding, the tensile strength of the aluminum alloy plate is 445MPa, the yield strength is 398MPa, the elongation after fracture is 18.5%, and the MIG welding coefficient is 0.63. After exposure at 300℃ for 100 hours, the tensile strength is 321MPa, the yield strength is 288MPa, and the elongation after fracture is 28.5%; after exposure at 350℃ for 100 hours, the tensile strength is 236MPa, the yield strength is 211MPa, and the elongation after fracture is 35.0%; it can be seen that the performance of the plate described in comparative example 5 after heat exposure at 300℃ is only about 72% of that at room temperature, and the performance after heat exposure at 350℃ is only about 53% of that at room temperature.

[0178] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A heat-resistant, high-strength, weldable rare earth aluminum alloy, comprising: 0~0.1wt% silicon; 0~0.2wt% iron; 5.5wt%~7.1wt% magnesium; 0.7wt%~1.2wt% manganese; 0.05wt%~0.15wt% zirconium; 0.05wt%~0.18wt% scandium; 1.2wt%~2.0wt% zinc; 0.03wt%~0.07wt% titanium; 0.04wt%~0.09wt% nickel; The balance is Al; Among them, the total amount of impurities is ≤0.15%.

2. The heat-resistant, high-strength, weldable rare earth aluminum alloy according to claim 1, characterized in that: include: 0~0.1wt% silicon; 0~0.2wt% iron; 5.6 wt% to 6.8 wt% magnesium; 0.7 wt% to 1.2 wt% manganese; 0.08 wt% to 0.12 wt% zirconium; 0.07 wt%~0.16 wt% scandium; 1.25 wt% to 1.8 wt% zinc; 0.04 wt% to 0.06 wt% titanium; 0.045 wt% to 0.09 wt% nickel; The balance is Al; Among them, the total amount of impurities is ≤0.15%.

3. The heat-resistant, high-strength, weldable rare earth aluminum alloy according to claim 2, characterized in that: include: 0~0.1wt% silicon; 0~0.2wt% iron; 5.7 wt% to 6.6 wt% magnesium; 0.7 wt% to 1.2 wt% manganese; 0.09 wt% to 0.12 wt% zirconium; 0.09 wt%~0.12wt% scandium; 1.25 wt% to 1.7 wt% zinc; 0.04 wt% to 0.06 wt% titanium; 0.045 wt% to 0.09 wt% nickel; The balance is Al; Among them, the total amount of impurities is ≤0.15%.

4. The method for preparing the heat-resistant, high-strength, weldable rare earth aluminum alloy according to any one of claims 1 to 3, comprising the following steps: (1) Preparing ingredients according to the formula, melting, refining and casting to obtain aluminum alloy ingots; (2) homogenizing the aluminum alloy ingot; (3) hot rolling and cold rolling the aluminum alloy ingot after the homogenization treatment in sequence to obtain an aluminum alloy slab; (4) The aluminum alloy slab is subjected to a stabilization annealing treatment.

5. The preparation method according to claim 4, characterized in that: The step (2) comprises: The aluminum alloy ingot billet is heated to 270°C~280°C, kept warm for 10 hours~14 hours, then heated to 410°C~430°C, kept warm for 10 hours~14 hours, and finally heated to 450°C~470°C, kept warm for 5 hours~7 hours, and cooled.

6. The preparation method according to claim 5, characterized in that: In the step (2), the cooling is strong wind cooling.

7. The preparation method according to claim 4, characterized in that: In the step (3), the hot rolling temperature is 450°C to 470°C, and the hot rolling reduction is 65% to 75%.

8. The preparation method according to claim 7, characterized in that: In the step (3), the cold rolling temperature is room temperature, and the cold rolling reduction is 65% to 75%.

9. The preparation method according to claim 8, characterized in that: In the step (3), after hot rolling and before cold rolling, the following steps are further included: The hot rolled slab is intermediate annealed.

10. The preparation method according to claim 4, characterized in that: In the step (4), the temperature of the stabilization annealing treatment is 160° C. to 200° C., and the time is 3 hours to 5 hours.