Cerium-containing high-strength creep-resistant aluminum-copper-scandium alloy and preparation method thereof

Abstract

The application discloses a kind of high-strength creep-resistant cerium-containing aluminum copper scandium alloys and preparation method, by mass percentage, including Cu 2.5-5.5%, Ce 0.1-1%, Sc 0.1-0.50%, Si 0.02-0.10%, the balance is Al and inevitable impurities;Preparation process includes two-stage homogenization treatment and artificial failure treatment, two-stage homogenization treatment is used to eliminate the micron crystalline phase of θ-Al2Cu formed in the process of smelting and solidification and composition segregation, so that solute atoms are fully resolubilized, and high concentration vacancies are retained by subsequent quenching, artificial aging treatment precipitates nanoscale θ'-Al2Cu and Sc-rich strengthening phase, to obtain cerium-containing high-strength creep-resistant aluminum copper scandium alloy.The application provides Ce-containing alloy phase compared with aging precipitation type Al-Cu and Al-Cu-Sc alloy has more excellent comprehensive tensile mechanical properties and creep resistance.

Description

TECHNICAL FIELD

[0001] The application relates to the field of light metal structural materials, and particularly relates to a high-strength creep-resistant cerium-containing aluminum-copper-scandium alloy and a preparation method. BACKGROUND

[0002] Aluminum alloys have been widely used in high-end manufacturing fields such as transportation and aerospace due to their low density, high specific strength, high thermal conductivity and excellent processability. The development of new strengthening ideas and additive manufacturing technology also brings new vitality to the application of aluminum alloys in high strength and toughness matching, high thermal stability and material lightweight. Al doping with Cu, Mg and Zn as the representative of main alloying elements with high solid solubility is still the most common toughening idea to improve the mechanical properties of aluminum alloys through solute atom solid solution strengthening and precipitate phase aging strengthening. However, although high-density nanoscale precipitates can provide high strengthening increment at room temperature, the diffusion of the constituent elements in the aluminum matrix is fast and the solid solubility is high, which leads to the rapid dissolution and ripening of the precipitates after short-time thermal exposure above 200 DEG C, resulting in significant decline in mechanical properties. This greatly limits the feasibility of the application of traditional aging strengthened aluminum alloys in high-temperature service environments such as gas turbines.

[0003] In order to improve the stability of the theta'-Al2Cu strengthening phase of the Al-Cu alloy at high temperatures, in addition to the interface engineering design based on the interface segregation of solute atoms, a large number of studies in recent years aim to build multiple heterogeneous structures including grain size gradient (fine grain / subgrain, coarse grain, etc.), two-phase / multi-phase composition gradient (eutectic phase, precipitate phase, dispersion phase, composite strengthening phase, etc.) and layered / multi-stage precipitate density gradient (such as core-shell nanoscale precipitate Al3(Zr, Sc, Er)), and have made a series of breakthroughs in the alternation of microstructure stabilization ideas. One of the important achievements is the research and development of Al-Cu-Sc alloy materials. As a typical representative of Al-Cu-Sc alloy, documents 1 "A high-strength heat-resistant low-scandium composite micro-alloyed Al-Cu alloy and its heat treatment process (ZL202010328095.5)" and document 2 "A scandium-iron-silicon composite micro-alloyed anti-creep Al-Cu alloy and its heat treatment process (ZL202010329047.8)" highlight the contribution of the strong segregation of Sc atoms at the theta'-Al2Cu / alpha-Al interface to the thermal stability of the theta'-Al2Cu strengthening phase in the high-temperature microstructure evolution process. However, under the complex heat treatment process, the theta'-Al2Cu+Al3Sc double precipitate strengthening structure still cannot be perfectly "co-stable", and the low utilization efficiency of Sc atoms and the imperfect partitioning mode restrict the ability of Sc alloying to protect Al-Cu-based alloys under high-temperature service conditions. SUMMARY

[0004] In view of the problems in the prior art, the application provides a high-strength creep-resistant aluminum-copper-scandium alloy containing cerium and a preparation method thereof, which utilizes the extremely low-cost high-abundance rare earth element Ce to improve the strengthening and thermal stabilization effect of the expensive rare earth element Sc in the Al-Cu alloy, and greatly improves the room temperature ductility and the strength and creep resistance at 300 DEG C of the Al-Cu-Sc alloy.

[0005] The application is realized by the following technical scheme:

[0006] The high-strength creep-resistant aluminum-copper-scandium alloy containing cerium comprises, in percentage by mass, Cu 2.5-5.5%, Ce 0.1-1%, Sc 0.1-0.50%, Si 0.02-0.10%, and the balance of Al and inevitable impurities.

[0007] Preferably, in the impurities, the mass percentage of Fe element is 0.05-0.15%, and the mass percentage of each of the remaining impurity elements is less than 0.10%.

[0008] The preparation method of the high-strength creep-resistant aluminum-copper-scandium alloy containing cerium comprises the following steps:

[0009] Step 1, performing two-stage homogenization treatment on the alloy ingot;

[0010] Step 2, performing aging treatment on the alloy ingot obtained in step 1;

[0011] holding at 240-250 DEG C for 12-48 hours, and cooling to room temperature to obtain the high-strength creep-resistant aluminum-copper-scandium alloy containing cerium;

[0012] or, holding at 240-250 DEG C for 12-48 hours, then heating to 300 DEG C and holding for 8-24 hours, and cooling to room temperature to obtain the high-strength creep-resistant aluminum-copper-scandium alloy containing cerium.

[0013] Preferably, in step 1, the raw materials are mixed uniformly and then smelted to obtain the alloy ingot according to the mass percentage.

[0014] Preferably, the smelting adopts a metal casting mold or a sand mold casting mode.

[0015] Preferably, in step 1, the two-stage homogenization treatment method is as follows:

[0016] holding at 450 DEG C for 4-5 hours, then holding at 570-580 DEG C for 3-24 hours, and then quenching.

[0017] Preferably, the quenching mode is water quenching or oil quenching.

[0018] Preferably, in step 2, the aging treatment method is as follows:

[0019] The alloy ingot is kept for 12-48 hours, and then heated to 300 DEG C at a heating rate of 0.25 DEG C-1 DEG C, and then kept again.

[0020] Preferably, the cooling mode in step 2 is furnace cooling or air cooling.

[0021] Compared with the prior art, the application has the following beneficial technical effects:

[0022] The application provides a preparation method of a high-strength anti-creep Al-Cu-Sc alloy containing Ce, and the Ce alloying effect is supplemented by double-stage artificial aging treatment, and compared with an Al-Cu-Sc alloy with the same strengthening equivalent, the room-temperature yield strength and tensile strength of the Ce-containing Al-Cu-Sc alloy can be up to 264 MPa and 336 MPa respectively, and the increase can be up to 15%, and the maximum fracture elongation can be basically flat. In the high-temperature application aspect, the Ce-containing Al-Cu-Sc alloy can realize the target of stable service in the high-temperature range of 300-400 DEG C (> 400 hours) and also has good high-temperature instantaneous tensile performance (the maximum instantaneous tensile strength at 300 DEG C is up to 127 MPa). The mechanism is that, firstly, the Ce increases the segregation concentration of Sc at the interface of the θ'-Al2Cu precipitated phase. The trace Ce atoms are combined with vacancies, the growth rate of the θ'-Al2Cu precipitated phase is reduced, so that the Sc has sufficient time to diffuse to the interface; secondly, the Ce eliminates the micron / submicron coarse Fe-rich crystalline phases (such as W-(Al, Cu, Sc) phase, alpha-Al8Fe2Si, beta-Al5FeSi, omega-Al7Cu2Fe, etc.) through the enrichment of Fe elements, the ductility of the alloy is improved, and the diffusion of Fe atoms to the interface is promoted, and the thermal stability of the θ'-Al2Cu is enhanced; in addition, the complex coupling between the eutectic phase load transfer (improving the creep resistance) and the precipitation strengthening (improving the basic strength) is synergistically optimized through the double-stage aging treatment, and the Ce-containing alloy provided by the application has better comprehensive tensile mechanical properties and anti-creep properties than the aging and precipitated Al-Cu and Al-Cu-Sc alloys. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 The room-temperature tensile engineering stress-engineering strain curve diagrams of the aluminum copper scandium alloys prepared in examples 1-4 of the application and the aluminum copper scandium alloys prepared in comparative examples 5-7 are shown in the figure;

[0024] Figure 2 The high-temperature tensile engineering stress-engineering strain curve diagrams of the aluminum copper scandium alloys prepared in examples 1 and 3 of the application and the aluminum copper scandium alloys prepared in comparative examples 5 and 6 at 300 DEG C are shown in the figure;

[0025] Figure 3The high-temperature tensile engineering stress-engineering strain curves of the aluminum copper scandium alloys prepared in the embodiments 1-4 of the present application and the aluminum copper scandium alloys prepared in the comparative examples 6-7 at 300 DEG C are shown in the following table:

[0026] Figure 4 The steady-state creep rates epsilon of the aluminum copper scandium alloys prepared in the embodiments 1 and 3 of the present application and the aluminum copper scandium alloys prepared in the comparative examples 5-6 at 300 DEG C are shown in the following table: · The double logarithmic coordinate graph of the relationship between the steady-state creep rate epsilon and the applied tensile load sigma is shown in the following figure:

[0027] Figure 5 The 3DAP graph of the strong enrichment of Ce impurity atoms in the embodiment 1 of the present application is shown in the following figure. DETAILED DESCRIPTION

[0028] The present application will be further described in detail below with reference to the accompanying drawings, which are provided to explain the present application rather than to limit the present application.

[0029] A high-strength creep-resistant aluminum copper scandium alloy containing cerium, comprising, in mass percentage, Cu 2.5-5.5%, Ce 0.1-1%, Sc 0.1-0.50%, Si 0.02-0.10%, and the balance of Al and inevitable impurities.

[0030] Due to the absorption of Ce to Fe, the mass percentage of Fe impurity element is 0.05-0.15%, and the mass percentage of the remaining impurity elements is less than 0.10%.

[0031] The high-strength creep-resistant aluminum copper scandium alloy containing cerium is obtained by casting in a metal mold or a sand mold and then performing subsequent heat treatment processing in the as-cast state.

[0032] The main microstructure characteristics of the high-strength creep-resistant aluminum copper scandium alloy containing cerium are that a large number of Al8Cu4Ce micron-scale heat-resistant eutectic phases with a thickness of less than 10 microns gradually and continuously distribute along the grain boundaries with the increase of the Ce content, and a high-density of θ'-Al2Cu with a thickness of less than 8 nm and Sc-rich agglomerates with an average particle size of less than 2 nm are inside the grains. After high-temperature aging treatment, the Sc-rich agglomerates gradually transform into nanometer Al3Sc precipitates in situ, and the number density and the anti-coarsening performance are not reduced. In addition to forming the heat-resistant eutectic phase that absorbs the harmful element Fe, the Ce alloying also increases the segregation amount of Sc at the θ'-Al2Cu / alpha-Al interface, so that the high-temperature creep resistance of the Ce-containing alloy material is improved.

[0033] A preparation method of a high-strength creep-resistant aluminum copper scandium alloy containing cerium, comprising the following steps:

[0034] Step 1, uniformly mixing the elements according to the mass percentage and then smelting to obtain an alloy ingot;

[0035] Step 2, the alloy ingot obtained in step 1 is subjected to two-stage homogenization treatment, specifically as follows:

[0036] First, the furnace temperature is kept at 450 DEG C for 4-5 hours, then the furnace is raised in temperature or directly transferred to a furnace temperature of 570-580 DEG C, the heating rate is determined according to the size of the workpiece, the holding time is 12 hours, and then immediately water quenching / oil quenching. The overall holding time in the homogenization stage is not less than 3 hours and not more than 24 hours.

[0037] Considering that the homogenization temperature is close to the eutectic temperature of the Al-Cu-Ce ternary alloy, if the temperature control is not accurate, there is a risk of overburning, and the temperature floating interval needs to be accurately controlled within ±1 DEG C.

[0038] The two-stage homogenization treatment is used to eliminate the micron-sized θ-Al2Cu crystalline phase and composition segregation formed during smelting and solidification, to fully dissolve solute atoms, and to retain high concentration vacancies through subsequent quenching, thereby preparing for aging treatment.

[0039] Step 3, artificial aging treatment is performed to precipitate nanoscale θ'-Al2Cu and Sc-rich strengthening phase, thereby obtaining a high-strength creep-resistant aluminum copper scandium alloy containing cerium.

[0040] The aging treatment process is divided into two cases, as follows:

[0041] (1) If the room temperature performance of the high-strength creep-resistant aluminum copper scandium alloy containing cerium is emphasized, the temperature is kept at 240-250 DEG C for 12-48 hours, and the furnace is cooled or air-cooled after being taken out;

[0042] (2) If the high-temperature performance of the high-strength creep-resistant aluminum copper scandium alloy containing cerium is emphasized, the temperature is kept at 240-250 DEG C for 12-48 hours, and then the temperature is raised to 300 DEG C at a rate of 0.25 DEG C to 1 DEG C, and then kept at 300 DEG C for 8-24 hours until the entire test piece reaches 300 DEG C, and then the furnace is cooled or air-cooled after being taken out.

[0043] Example 1

[0044] A method for preparing a high-strength creep-resistant aluminum copper scandium alloy containing cerium, comprising the following steps:

[0045] Step 1, an alloy ingot is prepared by adopting metal copper mold casting, the composition of the alloy ingot includes, by mass percentage, 4.0% Cu, 0.3% Ce, 0.18% Sc, 0.05% Si, the balance being Al and unavoidable impurities, and the impurities include 0.03% Zn and 0.12% Fe.

[0046] Step 2, the alloy ingot obtained in step 1 is subjected to two-stage homogenization treatment, and the process parameters of the two-stage homogenization treatment are as follows:

[0047] aging at 245℃ for 24 hours, and then air cooling to room temperature after taking out the sample, to obtain the high-strength creep-resistant cerium-containing aluminum copper scandium alloy.

[0048] Step 3, aging the alloy ingot after the homogenization treatment of step 2 at 245℃ for 24 hours, and then air cooling to room temperature after taking out the sample, to obtain the high-strength creep-resistant cerium-containing aluminum copper scandium alloy.

[0049] Example 2

[0050] A method for preparing a high-strength creep-resistant cerium-containing aluminum copper scandium alloy, comprising the following steps:

[0051] Step 1, an alloy ingot is prepared by metal copper mold casting, and the composition of the alloy ingot includes, by mass percentage, 4.1% Cu, 0.3% Ce, 0.20% Sc, 0.05% Si, and the balance of Al and unavoidable impurities, wherein the impurities include 0.03% Zn and 0.12% Fe.

[0052] Step 2, the alloy ingot obtained in step 1 is subjected to two-stage homogenization treatment.

[0053] The process parameters of the two-stage homogenization treatment are specifically: aging at 450℃ for 5 hours, and then aging at 575℃ for 12 hours, and then immediately quenching in cold water.

[0054] Step 3, aging the alloy ingot after the homogenization treatment of step 2 at 245℃ for 24 hours, and then air cooling to room temperature after taking out the sample, to obtain the high-strength creep-resistant cerium-containing aluminum copper scandium alloy.

[0055] Example 3

[0056] A method for preparing a high-strength creep-resistant cerium-containing aluminum copper scandium alloy, comprising the following steps:

[0057] Step 1, an alloy ingot is prepared by metal copper mold casting, and the composition of the alloy ingot includes, by mass percentage, 4.3% Cu, 1.0% Ce, 0.22% Sc, 0.04% Si, and the balance of Al and unavoidable impurities, wherein the impurities include 0.03% Zn and 0.09% Fe.

[0058] The two-stage homogenization treatment of step 2 and the artificial aging treatment of step 3 are the same as those of Example 1, and are not repeated here.

[0059] Example 4

[0060] A method for preparing a high-strength creep-resistant cerium-containing aluminum copper scandium alloy, comprising the following steps:

[0061] Step 1, an alloy ingot is prepared by adopting metal copper mold casting, the composition of the alloy ingot includes, by mass percentage, 4.3% Cu, 0.9% Ce, 0.22% Sc, 0.04% Si, the balance being Al and inevitable impurities, and the impurities include 0.03% Zn and 0.10% Fe.

[0062] Step 2, the alloy ingot obtained in step 1 is subjected to two-stage homogenization treatment.

[0063] The process parameters of the two-stage homogenization treatment are specifically as follows: heat preservation at 450℃ for 5 hours, then heat preservation at 575℃ for 12 hours, and then immediately quenching in cold water.

[0064] Step 3, the alloy ingot subjected to the homogenization treatment in step 2 is aged at 245℃ for 24 hours, then heated to 300℃ at a heating rate of 0.6℃, and then air-cooled to room temperature after heat preservation at 300℃ for 8 hours, to obtain a high-strength creep-resistant aluminum copper scandium alloy containing cerium.

[0065] Comparative Example 1

[0066] A preparation method of an aluminum copper scandium alloy not containing cerium, comprising the following steps:

[0067] Step 1, an alloy ingot is prepared by adopting metal copper mold casting, the composition of the alloy ingot includes, by mass percentage, 2.5% Cu, 0.28% Sc, 0.03% Si, the balance being Al and inevitable impurities, and the impurities include 0.02% Zn and 0.15% Fe.

[0068] The heat treatment processes of steps 2 and 3 are the same as those of Example 1.

[0069] Comparative Example 6

[0070] A preparation method of an aluminum copper scandium alloy containing cerium, comprising the following steps:

[0071] Step 1, an alloy ingot is prepared by adopting metal copper mold casting, the composition of the alloy ingot includes, by mass percentage, 3.8% Cu, 1.8% Ce, 0.19% Sc, 0.03% Si, the balance being Al and inevitable impurities, and the impurities include 0.02% Zn and 0.15% Fe.

[0072] The heat treatment processes of steps 2 and 3 are the same as those of Example 1.

[0073] Comparative Example 7

[0074] A preparation method of an aluminum copper scandium alloy containing cerium, comprising the following steps:

[0075] Step 1, an alloy ingot is prepared by adopting metal copper mold casting, the composition of the alloy ingot includes 3.9% Cu, 2.0% Ce, 0.21% Sc, 0.03% Si, and the balance of Al and inevitable impurities, and the impurities include 0.02% Zn and 0.11% Fe.

[0076] Step 2, the alloy ingot obtained in step 1 is subjected to two-stage homogenization treatment, and the process parameters of the two-stage homogenization treatment are as follows:

[0077] holding at 450 ℃ for 5 hours, then heating to 575 ℃ and holding for 12 hours, and then immediately quenching in cold water;

[0078] Step 3, the alloy ingot subjected to the homogenization treatment in step 2 is aged at 245 ℃ for 24 hours, then heated to 300 ℃ at a heating rate of 0.25 ℃, and held for 24 hours, and then air-cooled to room temperature to obtain a high-strength creep-resistant aluminum copper scandium alloy containing cerium.

[0079] Example 8

[0080] A preparation method of a high-strength creep-resistant aluminum copper scandium alloy containing cerium, comprising the following steps:

[0081] Step 1, an alloy ingot is prepared by adopting metal copper mold casting, the composition of the alloy ingot includes 2.5% Cu, 0.1% Ce, 0.5% Sc, 0.02% Si, and the balance of Al and inevitable impurities, and the impurities include 0.03% Zn and 0.10% Fe.

[0082] Step 2, holding at 450 ℃ for 4 hours, then directly heating to 580 ℃ and holding for 12 hours, and then immediately oil quenching;

[0083] Step 3, the alloy ingot subjected to the homogenization treatment in step 2 is aged at 240 ℃ for 12 hours, and then the sample is taken out and cooled to room temperature in the furnace to obtain a high-strength creep-resistant aluminum copper scandium alloy containing cerium.

[0084] Example 9

[0085] A preparation method of a high-strength creep-resistant aluminum copper scandium alloy containing cerium, comprising the following steps:

[0086] Step 1, an alloy ingot is prepared by adopting metal copper mold casting, the composition of the alloy ingot includes 5.5% Cu, 0.5% Ce, 0.1% Sc, 0.1% Si, and the balance of Al and inevitable impurities, and the impurities include 0.03% Zn and 0.10% Fe.

[0087] Step 2, holding at 450 ℃ for 4.5 hours, then heating to 570 ℃ and holding for 12 hours in the furnace, and then immediately oil quenching;

[0088] Step 3, the alloy ingot after homogenization treatment in step 2 is aged at 250℃ for 24 hours, then heated to 300℃ at a heating rate of 1℃, and after holding for 18 hours, cooled to room temperature in the furnace to obtain a high-strength creep-resistant cerium-containing aluminum copper scandium alloy.

[0089] The tensile specimens of Examples 1-4 and Comparative Examples 5-7 were measured for room temperature tensile mechanical properties according to GB / T1173-1995 national standard. The experimental results are summarized in Table 1. It can be seen that the low cerium / two-stage aging Examples 2, 4 designed by the application have more excellent room temperature strength and toughness matching than the no (high) cerium / single-stage aging Comparative Examples 5-6.

[0090] The tensile specimens of Examples 1-4 and Comparative Examples 5-7 were measured for high temperature tensile properties at 300℃ according to GB / T2039-2012 national standard. The experimental results are summarized in Table 2. It can be seen that the low cerium / two-stage aging Example 2 designed by the application has more excellent high temperature strength and toughness matching than the no (high) cerium / single-stage aging Comparative Examples 5-6.

[0091] The creep tensile specimens of Examples 1-2 and Comparative Examples 5-6 were measured for tensile creep mechanical properties at 300℃ according to GB / T2039-2012 national standard. The experimental results are summarized in Table 3. It can be seen that the Examples 1-2 designed by the application have much lower steady-state creep rate and higher creep life than the Comparative Examples 5-6.

[0092] Table 1 is a comparison table of room temperature tensile mechanical properties of cerium-containing high-strength creep-resistant Al-Cu-Sc alloy examples and comparative examples.

[0093]

[0094]

[0095] Table 2 is a comparison table of 300℃ tensile mechanical properties of cerium-containing high-strength creep-resistant Al-Cu-Sc alloy examples and comparative examples.

[0096] Example code Yield strength / MPa Tensile strength / MPa Elongation / % Example 1 48 64 34 Example 2 86 127 15 Example 3 45 60 48 Example 4 70 90 10 Comparative Example 5 74 94 8 Comparative Example 6 44 59 40 Comparative Example 7 65 87 17

[0097] Table 3 is a comparison table of 300℃ creep properties of cerium-containing high-strength creep-resistant Al-Cu-Sc alloy examples and comparative examples.

[0098]

[0099]

[0100] Figure 1The tensile mechanical properties of Examples 1-4 and Comparative Examples 5-7 at room temperature were compared. The results showed that the low Ce content alloy of Example 2 (0.3wt.%) after double-stage aging had lower yield strength than Example 1 of single-stage aging, but the elongation and tensile strength were significantly improved, showing better strain hardening ability. Similarly, similar rules were also shown in the comparison of 1wt.% Ce group (Examples 3-4). While the low Ce content alloy had higher yield strength and tensile strength than the high Ce content alloy (>1.0wt.%) of Comparative Examples 6-7, which limited the composition range of Ce addition. It is worth noting that by comparing the Ce-containing / non-Ce-containing alloys under the same heat treatment conditions and room temperature strengthening equivalent (Example 3 vs. Comparative Example 5), it can be found that the Ce-containing alloy of Example 3 has better comprehensive mechanical properties at room temperature.

[0101] Figure 2 The high temperature tensile properties of Examples 1, 3 and Comparative Examples 5-6 at 300°C were compared. The results showed that after simple single-stage aging treatment, the instantaneous strength of the low Ce content alloys of Examples 1, 3 and the high Ce content alloy of Comparative Example 6 at 300°C was still lower than that of the non-Ce alloy of Comparative Example 5, indicating that the conventional heat treatment process is not suitable for high temperature application for the alloys of the present application.

[0102] Figure 3 Examples 2, 4 were added, combined with Figure 2 The high temperature tensile properties of Examples 1-4 and Comparative Examples 5-7 at 300°C were compared to highlight the positive effect of Ce alloying effect and double-stage aging process on high temperature mechanical properties. The results showed that the instantaneous tensile strength of the double-stage aging alloys (2, 4) at 300°C could reach 1.5-2 times of that of the single-stage aging alloys (1, 3). Further, the double-stage aging alloys also followed the "Ce content— mechanical property" influence rule of the single-stage aging alloys, and the low Ce content alloy of Example 2 after double-stage aging showed the largest strengthening increment and the best strength-toughness match, which exhibited excellent short-term high temperature tensile properties in this severe high temperature service environment.

[0103] Figure 4 The steady-state creep rate ε of Examples 1, 3 and Comparative Examples 5-6 provided by the present application at 300°C was summarized · and the external tensile load σ. The results showed that although the comprehensive creep properties deteriorated with the increase of Ce content, showing greater stress sensitivity, the Ce-containing alloy material provided by the present application had higher creep resistance than the non-Ce alloy material, and had a lower steady-state creep rate under the same external load (see Table 3).

[0104] Figure 5The 3DAP characterization of the micro-zone element distribution of the cerium-rich heat-resistant eutectic phase in Example 1 of the low-cerium-content alloy in the single-stage aging state is shown. The results show that each micro-alloying impurity element is effectively attracted by the eutectic phase to a certain extent, that is, the addition of Ce affects the partitioning relationship of other solute atoms between each component phase and the phase interface.

[0105] The above merely illustrates the technical idea of the present application and cannot limit the protection scope of the present application. Any modification made according to the technical idea of the present application on the basis of the technical solutions falls within the protection scope of the claims of the present application.

Claims

1. A high-strength, creep-resistant aluminum-copper-scandium alloy containing cerium, characterized in that, The alloy comprises Cu 2.5-5.5%, Ce 0.1-1%, Sc 0.1-0.50%, Si 0.02-0.10% by mass, and the balance of Al and inevitable impurities. The preparation method of the high-strength creep-resistant aluminum copper scandium alloy containing cerium comprises the following steps: Step 1, the alloy ingot is subjected to two-stage homogenization treatment, and the method is as follows: The temperature is kept at 450 DEG C for 4-5 hours, then kept at 570-580 DEG C for 3-24 hours, and then quenched; Step 2, the alloy ingot obtained in step 1 is subjected to aging treatment; The temperature is kept at 240-250 DEG C for 12-48 hours, and then cooled to room temperature to obtain the high-strength creep-resistant aluminum copper scandium alloy containing cerium; Or, the temperature is kept at 240-250 DEG C for 12-48 hours, then heated to 300 DEG C at a heating rate of 0.25 DEG C-1 DEG C and kept for 8-24 hours again, and then cooled to room temperature to obtain the high-strength creep-resistant aluminum copper scandium alloy containing cerium. The Ce increases the segregation concentration of Sc at the interface of the θ -Al2Cu precipitate, and the trace Ce atoms reduce the growth rate of the θ -Al2Cu precipitate by combining with vacancies, so that Sc has sufficient time to diffuse to the interface.

2. A high-strength, creep-resistant aluminum-copper-scandium alloy containing cerium according to claim 1, characterized in that In the impurities, the mass percentage of Fe element is 0.05-0.15%, and the mass percentage of each of the other impurity elements is less than 0.10%.

3. A high-strength, creep-resistant cerium-containing aluminum copper scandium alloy as recited in claim 1, wherein, In step 1, the raw materials are mixed uniformly according to the mass percentage, and then subjected to smelting to obtain the alloy ingot.

4. A high-strength, creep-resistant cerium-containing aluminum copper scandium alloy as claimed in claim 3, characterized in that The smelting adopts a metal casting mold or a sand mold casting mode.

5. A high-strength, creep-resistant cerium-containing aluminum copper scandium alloy as defined in claim 1, characterized in that, The quenching mode is water quenching or oil quenching.

6. A high-strength, creep-resistant cerium-containing aluminum copper scandium alloy as defined in claim 1, characterized in that, The cooling in step 2 is furnace cooling or air cooling.

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