Ce-Mg-containing high-strength heat-resistant aluminum alloy and preparation method thereof
阅读说明：本技术 一种含Ce-Mg高强耐热铝合金及其制备方法 (Ce-Mg-containing high-strength heat-resistant aluminum alloy and preparation method thereof ) 是由 管仁国 叶洁云 付莹 张晋 铁镝 陈继强 李冰 王长峰 姜巨福 李晓阳 于 2020-12-09 设计创作，主要内容包括：本发明涉及到一种含Ce-Mg高强耐热铝合金及其制备方法,属于金属材料工程领域,其化学成分按照重量百分比为：Ce:8～12%；Mg:4～8%；余量为Al。其制备方法步骤为：1)熔炼；2)浇注,快速凝固；本发明的耐热铝合金主要利用Ce的添加形成Al-(11)Ce-3金属间化合物来提高耐热性能,通过Mg元素的固溶来提高高温强度。本发明的有益效果在于,高温服役过程中的屈服强度不降低反而增高：室温的屈服强度为180～210MPa,在400℃热暴露1000h后的屈服强度为200MPa～250MPa。本发明不需要添加多种微合金元素,设计成本低,制备工艺流程短,稳定性高,可用于耐热要求高的铸造铝合金。(The invention relates to a Ce-Mg-containing high-strength heat-resistant aluminum alloy and a preparation method thereof, belonging to the field of metal material engineering, wherein the Ce-Mg-containing high-strength heat-resistant aluminum alloy comprises the following chemical components in percentage by weight: 8-12% of Ce; 4-8% of Mg; the balance being Al. The preparation method comprises the following steps: 1) smelting; 2) pouring and quickly solidifying; the heat-resistant aluminum alloy of the invention mainly utilizes the addition of Ce to form Al 11 Ce 3 The intermetallic compound improves heat resistance, and the solid solution of Mg element improves high-temperature strength. The invention has the advantages that the yield strength in the high-temperature service process is not reduced but increased: the yield strength at room temperature is 180-210 MPa, and the yield strength after thermal exposure for 1000 hours at 400 ℃ is 200-250 MPa. The invention does not need to add a plurality of micro-alloy elements, has low design cost, short preparation process flow and high stability, and can be used for casting aluminum alloy with high heat-resisting requirement.)
1. The Ce-Mg-containing high-strength heat-resistant aluminum alloy is characterized by comprising the following components in percentage by weight: 8 to 12 percent of Ce; 4 to 8 percent of Mg; the balance being Al.
2. A Ce-Mg-containing high strength heat resistant aluminum alloy according to claim 1, wherein the purity of Al is more than 99.9%.
3. A Ce-Mg-containing high strength heat resistant aluminum alloy according to claim 1, wherein the Mg purity is greater than 99.9%.
4. The method for preparing the Ce-Mg-containing high-strength heat-resistant aluminum alloy according to claim 1, which is characterized by comprising the following steps:
s1: preparing a Ce simple substance and an Al simple substance into an aluminum cerium alloy, and purifying the prepared aluminum cerium alloy;
s2: according to the chemical components and the stoichiometric ratio of the alloy, the consumption of the required raw materials is calculated, the industrial pure aluminum ingot, the magnesium ingot and the aluminum cerium alloy raw materials are preheated to 160-180 ℃, and the temperature is kept for 30-50 minutes;
s3: adding preheated industrial pure aluminum and 2/3 aluminum-cerium alloy into a preheated crucible, heating to 740-760 ℃ for melting, adding pure magnesium and the rest 1/3 aluminum-cerium alloy in sequence after all the aluminum-cerium alloy is melted, and keeping the temperature for 5 minutes; then reducing the furnace temperature to 720-730 ℃ and preserving the temperature for 15-20 min; after the furnace temperature is stable, removing the slag, and adding argon for refining for 5 minutes; further heating to 720-730 ℃, and preserving the heat for 10-15 min to obtain an alloy melt;
s4: pouring the alloy melt into a copper mold filled with liquid nitrogen coolant;
s5: and (5) demolding to obtain the Ce-Mg aluminum alloy.
5. The method for preparing the Ce-Mg-containing high-strength heat-resistant aluminum alloy according to claim 4, wherein the total amount of the alloy melt is 2/3 of the capacity of the crucible.
6. The method for preparing the Ce-Mg-containing high-strength heat-resistant aluminum alloy according to claim 5, wherein the wall thickness of the copper mold is controlled to be 10-15 mm.
7. The method for preparing Ce-Mg-containing high-strength heat-resistant aluminum alloy according to claim 5, wherein the flow rate of argon is controlled to be 0.45-0.60 m3In terms of hours.
Technical Field
The invention relates to the field of metal material engineering, in particular to a Ce-Mg-containing high-strength heat-resistant aluminum alloy and a preparation method thereof.
Background
Aluminum alloys are an ideal structural material due to their excellent castability, excellent machinability and low cost. The aluminum alloy solves the gap between the high density of steel materials and the high cost of titanium alloy materials, has high specific strength, corrosion resistance and high thermal conductivity, and is used for the automobile and aerospace industries. However, with the rapid development of aerospace and automobile industries, higher requirements, namely good high-temperature performance, are put forward on aluminum alloy materials. The typical strengthening mechanism of the traditional cast aluminum alloy (Al-Si, Al-Cu) is precipitation strengthening, namely, the rigidity and the strength of the alloy are increased by melting in alloy elements and carrying out heat treatment during the casting process to precipitate a second phase. Under the working condition that the temperature is higher than about 200 ℃, the second phase playing a strengthening role grows up at a fast speed due to the mass diffusion of alloy elements, becomes coarse, and the grains grow up fast, so that the strength performance of the alloy is greatly reduced.
The Chinese invention patent with the publication number of CN111321330A discloses an Al-Cu series heat-resistant aluminum alloy containing scandium and a preparation method thereof, the patent introduces a proper amount of rare earth elements Sc and Zr and alloy elements Cu, Mg and Mn, the alloy is modified by a multi-component micro-alloying method, wherein Sc and Al form a strengthening phase Al3Sc, Zr and Al form a strengthening phase ZrAl3The room temperature strength and the high temperature resistance of the aluminum alloy can be obviously improved. Will be cast intoThe formed cast alloy is subjected to heat treatment, so that the grain fineness of the alloy can be effectively improved. However, Sc is expensive, which increases the cost and limits the industrial application. On the other hand, Al3Sc and ZrAl3As the working time increases, the particles become gradually coarsened and may become inconsistent, thereby decreasing the strength properties at around 350 ℃.
The Chinese invention patent with the publication number of CN111235441A discloses a heat-resistant aluminum alloy containing Sb and a preparation method thereof, wherein Sb is added to form a high-melting-point strengthening phase AlSb phase to improve the high-temperature strength. However, since the addition of Sb easily causes element segregation during melting, the addition amount is only 0.2 to 0.5%, and therefore the amount of the generated strengthening phase is limited, resulting in a limited strengthening effect.
The Chinese patent with the publication number of CN111020315A discloses a rare earth heat-resistant aluminum alloy and a preparation method thereof, wherein Gd and Nd are added on the basis of Al-Zn-Mg-Cu. Since the strength is reduced by coarsening of the reinforcing phase particles at high temperature, the heat resistant temperature is about 250 ℃.
Chinese patent publication No. CN109402473A discloses an Al-Si-Cu-Mn heat-resistant aluminum alloy with high Fe content and a method for preparing the same, in which various transition group elements such as Mn, Fe, Cu, Ti, etc. are added on the basis of an Al-Si alloy to form various high-temperature-resistant and high-hardness intermetallic compounds to improve high-temperature performance. However, the alloy composition is complicated and melting is difficult. Therefore, a new technical solution needs to be designed to overcome the defects of the prior art.
Cerium is the most abundant rare earth element in the earth crust and the price is the cheapest. The Ce and the Al act at 645 ℃ to perform eutectic reaction to form Al11Ce3. At near eutectic temperature, Ce is hardly compatible with Al matrix and the solid solubility is less than 0.005%. Since Ce has a large atomic radius, it hinders transport-vacancy diffusion of solid solution atoms in the matrix, resulting in Al11Ce3Has a low decomposition ability. Thus, Al11Ce3And hardly decomposes below the eutectic temperature. Al of eutectic formation11Ce3Uniformly distributed in the crystalOn the boundary, the size of the eutectic lath is less than 100nm, and the eutectic laths are connected into a net structure and distributed. The rigid net structure with good thermal stability effectively improves the interface bonding strength and creep resistance of the alloy, inhibits the microcrack expansion between grain boundaries, and improves the high-temperature strength of the alloy. Meanwhile, the Ce element can effectively reduce the viscosity of pure aluminum, thereby effectively improving the castability of the Al-Ce alloy.
Mg is an effective solid solution strengthening element, and the addition of Mg in the Al-Ce alloy does not cause the change of the composition of intermetallic compounds, but causes the crystal lattice distortion of an aluminum matrix to generate the solid solution strengthening effect in the matrix, thereby improving the yield strength of the alloy. Therefore, the solid solubility of Mg in an Al matrix is increased along with the increase of the service temperature, and the diffusion of Mg element is more and more uniform along with the increase of time, so that the strength performance of the alloy is not reduced but is increased.
Based on the method, a novel rapid-solidification high-strength heat-resistant casting aluminum-cerium-magnesium-alloy material is developed and developed, and the high-temperature stability of cerium and the high-temperature solid solution strengthening effect of magnesium are exerted, so that the requirements of various industries on the high-temperature performance of the casting aluminum-alloy material are met.
Disclosure of Invention
The scheme aims to provide the Ce-Mg-containing high-strength heat-resistant aluminum alloy with good thermal stability.
In order to achieve the aim, the scheme provides a Ce-Mg-containing high-strength heat-resistant aluminum alloy which comprises the following components in percentage by weight: 8 to 12 percent of Ce; 4 to 8 percent of Mg; the balance being Al.
The invention also discloses a control method of the Ce-Mg-containing high-strength heat-resistant aluminum alloy, which comprises the following steps:
s1: preparing a Ce simple substance and an Al simple substance into an aluminum cerium alloy, and purifying the prepared aluminum cerium alloy;
s2: according to the chemical components and the stoichiometric ratio of the alloy, the consumption of the required raw materials is calculated, the industrial pure aluminum ingot, the magnesium ingot and the aluminum cerium alloy raw materials are preheated to 160-180 ℃, and the temperature is kept for 30-50 minutes;
s3: adding preheated industrial pure aluminum and 2/3 aluminum-cerium alloy into a preheated crucible, heating to 740-760 ℃ for melting, adding pure magnesium and the rest 1/3 aluminum-cerium alloy in sequence after all the aluminum-cerium alloy is melted, and keeping the temperature for 5 minutes; then reducing the furnace temperature to 720-730 ℃ and preserving the temperature for 15-20 min; after the furnace temperature is stable, removing the slag, and adding argon for refining for 5 minutes; further heating to 720-730 ℃, and preserving the heat for 10-15 min to obtain an alloy melt;
s4: pouring the alloy melt into a copper mold filled with liquid nitrogen coolant;
s5: and (5) demolding to obtain the Ce-Mg aluminum alloy.
The beneficial effect of this scheme: compared with the prior art, the invention has the following effects:
(1) the heat-resistant aluminum alloy prepared by the invention has simple components, simple smelting process, no need of heat treatment, low cost and good casting performance;
(2) the Ce content range of the invention is 8.0% -12.0%, and the range is selected to be as follows: one to improve castability; and Al capable of forming a rigid network structure in a sufficient amount due to a sufficient amount of Ce11Ce3A eutectic phase. The network can be maintained near the eutectic temperature without spheroidization, coarsening, or growth. The rigid net structure effectively improves the interface bonding strength and creep resistance of the alloy and inhibits the microcrack expansion between grain boundaries.
(3) In the invention, the addition range of Mg is 4.0-8.0%, and the addition of Mg does not cause the change of Al-Ce intermetallic compounds, but causes the lattice distortion of aluminum matrix to generate solid solution strengthening effect in the matrix, thereby improving the yield strength of the alloy. When the alloy is in service at high temperature, the yield strength is not reduced but increased along with the uniform diffusion of Mg element.
(4) By adopting a liquid nitrogen cooling and rapid solidification method, on one hand, the solid solubility of Mg in an Al matrix is improved, and on the other hand, the size of primary Al-Ce phase particles and the size and the spacing of eutectic Al-Ce photo layers can be effectively refined.
(5) Ce can effectively reduce the viscosity of the aluminum solution, so that the alloy has good casting performance and good fluidity and can form relatively complex castings.
The invention provides a high-strength heat-resistant aluminum alloy containing Ce-Mg, which is prepared by near eutectic compositionThe addition of Ce forms nano-grade Al with good thermal stability in the alloy11Ce3The net-shaped skeleton is rigid, so that the interface bonding strength and the creep resistance of the alloy are improved. By adding Mg element, the high-temperature solid solution strengthening effect is exerted, the strengthening effect in high-temperature service is achieved, and the high-temperature strength performance of the alloy is further improved. The alloy has the advantages of good casting performance, simple preparation process, low process requirement, no need of heat treatment and low cost. The Ce-Mg-containing high-strength heat-resistant aluminum alloy is mainly characterized by a primary Al-Ce phase, an Al-Mg phase and an Al-Ce eutectic phase; wherein the primary Al-Ce phase is distributed in submicron block shape, and the width of the lamella of the Al-Ce eutectic phase is between 50 and 100 nm. The yield strength of the Ce-Mg-containing high-strength heat-resistant aluminum alloy at room temperature is 180-210 MPa; the yield strength of the Ce-Mg-containing high-strength heat-resistant aluminum alloy after being exposed for 1000 hours at 400 ℃ is 230MPa to 260 MPa. When the alloy is in service at high temperature, Al11Ce3The rigid grid is not damaged, and simultaneously, the solid solution and the gradual diffusion of Mg element are uniform, so that the strength of the alloy is improved, and the problem of rapid reduction of the strength performance of the traditional aluminum alloy caused by the growth of strengthening phase particles at high temperature is solved.
Further, the purity of the Al is more than 99.9%. The purity of Al is more than 99.9%, and the prepared aluminum alloy has better effect.
Further, the purity of the Mg is more than 99.9%. The purity of Mg is more than 99.9 percent, and the prepared aluminum alloy has better effect.
Further, the total amount of the alloyed melt was 2/3 parts of the crucible capacity.
Further, the thickness of the copper die wall is controlled to be between 10 and 15 mm. The wall thickness of the copper mould is controlled between 10mm and 15mm, so that the copper mould is quickly solidified into a casting.
Further, the flow of the argon is controlled to be 0.45-0.60 m3In terms of hours. During pouring, the flow of argon is controlled to be 0.45-0.60 m3And the prepared aluminum alloy has better effect in one hour.
Drawings
FIG. 1 shows Al in the cast alloy of example 111Ce3SEM morphology of eutectic phase;
FIG. 2 shows the casting alloy of example 1 subjected to a 400 ℃ heat exposureAl after 1000h exposure11Ce3SEM morphology of eutectic phases.
Detailed Description
The following is further detailed by the specific embodiments:
example 1:
a Ce-Mg-containing high-strength heat-resistant aluminum alloy comprises the following components in percentage by weight: 10 percent of Ce; 6 percent of Mg; the balance being Al.
The preparation method of the Ce-Mg-containing high-strength heat-resistant aluminum alloy comprises the following steps:
s1: preparing a Ce simple substance and an Al simple substance into an aluminum cerium alloy, and purifying the prepared aluminum cerium alloy;
s2: according to the chemical components and the stoichiometric ratio of the alloy, the consumption of the required raw materials is calculated, the industrial pure aluminum ingot, the magnesium ingot and the aluminum cerium alloy raw materials are preheated to 170 ℃, and the temperature is kept for 40 minutes;
s3: adding preheated industrial pure aluminum and 2/3 aluminum-cerium alloy into a preheated crucible, heating to 760 ℃ for melting, adding pure magnesium and the rest 1/3 aluminum-cerium alloy in sequence after all the aluminum-cerium alloy is melted, and keeping the temperature for 5 minutes; then reducing the furnace temperature to 720 ℃ and preserving the temperature for 15 min; after the furnace temperature is stable, removing the slag, and adding argon for refining for 5 minutes; further heating to 730 ℃ and preserving the temperature for 10min to obtain an alloy melt;
s4: pouring the alloy melt into a copper mold filled with liquid nitrogen coolant;
s5: and (5) demolding to obtain the Ce-Mg aluminum alloy.
The weight percentages of the components of the Ce-Mg high strength heat resistant aluminum alloys of the other examples and comparative examples are shown in Table 1:
ce (substance)Volume percent)
Mg (mass percent)
Al (mass percent)
Example 2
8%
7%
85%
Example 3
10%
6%
84%
Example 4
8%
4%
88%
Example 5
8%
8%
84%
Example 6
12%
4%
84%
Example 7
12%
8%
80%
Comparative example 1
6%
6%
88%
Comparative example 2
14%
6%
80%
Comparative example 3
10%
3%
87%
Comparative example 4
10%
10%
80%
Comparative example 5
14%
3%
83%
Comparative example 6
14%
10%
76%
Comparative example 7
6%
10%
84%
Comparative example 8
6%
2%
92%
Comparative example 9
10%
6%
84%
Comparative example 10
8%
7%
85%
TABLE 1
Example 2 differs from example 1 in that: the mass percentages of Ce, Mg and Al added during the preparation are different.
Example 3 differs from example 1 in that: the preparation method is different, the wall thickness of the copper mold in step 3 in example 1 is 15mm, and the wall thickness of the copper mold in step 3 in example 3 is 10 mm.
Example 4 differs from example 1 in that: the mass percentages of Ce, Mg and Al added during the preparation are different.
Example 5 differs from example 1 in that: the mass percentages of Ce, Mg and Al added during the preparation are different.
Example 6 differs from example 1 in that: the mass percentages of Ce, Mg and Al added during the preparation are different.
Example 7 differs from example 1 in that: the mass percentages of Ce, Mg and Al added during the preparation are different.
Comparative example 1 differs from example 1 in that: the mass percentages of Ce and Al added during the preparation are different.
Comparative example 2 differs from example 1 in that: the mass percentages of Ce and Al added during the preparation are different.
Comparative example 3 differs from example 1 in that: the Mg and Al are added in different mass percentages during preparation.
Comparative example 4 differs from example 1 in that: the Mg and Al are added in different mass percentages during preparation.
Comparative example 5 differs from example 1 in that: the mass percentages of Ce, Mg and Al added during the preparation are different.
Comparative example 6 differs from example 1 in that: the mass percentages of Ce, Mg and Al added during the preparation are different.
Comparative example 7 differs from example 1 in that: the mass percentages of Ce, Mg and Al added during the preparation are different.
Comparative example 8 differs from example 1 in that: the mass percentages of Ce, Mg and Al added during the preparation are different.
Comparative example 9 differs from example 1 in that: the preparation method is different, step 3 in example 1 pours the alloy melt into a copper mould which is filled with liquid nitrogen coolant, and step 3 in comparative example 3 pours the alloy melt into a copper mould which is not filled with coolant.
Comparative example 10 differs from example 1 in that: the preparation methods are different, in the step 3 of the embodiment 1, preheated industrial pure aluminum and 2/3 aluminum-cerium alloy are added into a preheated crucible, the crucible is heated to 760 ℃ to be melted, after the aluminum-cerium alloy is completely melted, pure magnesium and the rest 1/3 aluminum-cerium alloy are sequentially added, the temperature is kept for 5 minutes, and the preparation materials are added in the step 3 in batches; in the step 3 of the comparative example 10, all the preheated industrial pure aluminum, the aluminum cerium alloy and the pure magnesium are added into the preheated crucible, the crucible is heated to 760 ℃ to be melted, after all the industrial pure aluminum, the aluminum cerium alloy and the rest 1/3 of the aluminum cerium alloy are sequentially added after all the industrial pure aluminum, the aluminum cerium alloy and the rest 1/3 of the aluminum cerium alloy are melted, the temperature is kept for 5 minutes, and the preparation materials are not added in batches in the step 3.
The room temperature yield strength and 400 ℃ heat exposure yield strength of the examples and comparative examples are shown in Table 2 according to relevant standard tests such as GB/T228.1-2010, GB/T228.2-2015 and the like:
room temperature yield strength
Strength of the product after being exposed for 1000h at 400 DEG C
Example 1
205MPa
241MPa
Example 2
192MPa
238MPa
Example 3
196MPa
252MPa
Example 4
200Mpa
240Mpa
Example 5
198Mpa
243Mpa
Example 6
194Mpa
250Mpa
Example 7
202Mpa
243Mpa
Comparative example 1
165MPa
212MPa
Comparative example 2
167Mpa
197Mpa
Comparative example 3
182MPa
220MPa
Comparative example 4
180Mpa
210Mpa
Comparative example 5
170Mpa
208Mpa
Comparative example 6
162Moa
195Mpa
Comparative example 7
169Mpa
202Mpa
Comparative example 8
161Mpa
195Mpa
Comparative example 9
160MPa
190MPa
Comparative example 10
172Mpa
210Mpa
TABLE 2
As can be seen from tables 1 and 2, the Ce-Mg-containing high strength heat resistant aluminum alloys obtained in examples 1, 2, 3, 4, 5, 6 and 7 have better room temperature yield strength and better yield strength after being exposed to 400 ℃ for 1000 h. Therefore, the optimum charge mass range of Ce:8 to 12 percent; the optimal feeding mass range of Mg is as follows: the aluminum alloy prepared by 4-8% of Al as the balance has better effect, better interface bonding strength and better creep resistance.
As can be seen from tables 1 and 2, the mass percent of Ce in comparative example 1 is 6%, which is lower than the mass percent range of Ce added, and the aluminum alloy prepared under the condition has poor effect, poor interface bonding strength and poor creep resistance.
As can be seen from tables 1 and 2, the mass percent of Ce in the comparative example 2 is 14%, which is higher than the best charging mass range of Ce, and the aluminum alloy prepared under the condition has poor effect, poor interface bonding strength and poor creep resistance.
As can be seen from tables 1 and 2, the mass percent of Mg in comparative example 3 is 3%, which is lower than the optimum feeding mass range of Mg, and the aluminum alloy prepared under the condition has poor effect, poor interface bonding strength and poor creep resistance.
As can be seen from tables 1 and 2, the mass percent of Mg in comparative example 4 is 10%, which is higher than the optimum feeding mass range of Mg, and the aluminum alloy prepared under the condition has poor effect, poor interface bonding strength and poor creep resistance.
As can be seen from tables 1 and 2, the mass percent of Ce in the comparative example 5 is 14%, which is higher than the optimum charging mass range of Ce, and the mass percent of Mg is 3%, which is lower than the optimum charging mass range of Mg, so that the aluminum alloy prepared under the conditions has poor effect, poor interface bonding strength and poor creep resistance.
As can be seen from tables 1 and 2, the mass percent of Ce in the comparative example 6 is 14%, which is higher than the optimum charging mass range of Ce, and the mass percent of Mg is 10%, which is higher than the optimum charging mass range of Mg, so that the aluminum alloy prepared under the conditions has poor effect, poor interface bonding strength and poor creep resistance.
As can be seen from tables 1 and 2, the mass percent of Ce in the comparative example 7 is 6% which is lower than the optimum charging mass range of Ce, and the mass percent of Mg is 10% which is higher than the optimum charging mass range of Mg, so that the aluminum alloy prepared under the conditions has poor effect, poor interface bonding strength and poor creep resistance.
As can be seen from tables 1 and 2, the mass percent of Ce in the comparative example 8 is 6% which is lower than the optimum charging mass range of Ce, and the mass percent of Mg is 2% which is lower than the optimum charging mass range of Mg, so that the aluminum alloy prepared under the conditions has poor effect, poor interface bonding strength and poor creep resistance.
As can be seen from tables 1 and 2, comparative example 9, in which Ce was 10% by mass, was in the optimum charging mass range for Ce, while Mg was 6% by mass, was in the optimum charging mass range for Mg, but the alloy melt was cast into a copper mold not fed with coolant at the time of production. The aluminum alloy prepared under the condition has poor effect, poor interface bonding strength and poor creep resistance.
As can be seen from tables 1 and 2, in comparative example 10, in which the prepared materials were mixed, the aluminum alloy obtained under such conditions was poor in effect, poor in interface bonding strength, and poor in creep resistance.
In summary, the Ce-Mg-containing high-strength heat-resistant aluminum alloy comprises the following components in percentage by weight: 8 to 12 percent of Ce; 4 to 8 percent of Mg; the aluminum alloy prepared by the balance of Al has better effect, better interface strength and better creep resistance, and meanwhile, the aluminum alloy prepared by pouring the alloy melt into a copper mold filled with liquid nitrogen coolant has better effect during preparation.
The heat-resistant aluminum alloy prepared by the invention has simple components, simple smelting process and no need of heat treatment,the cost is low, and the casting performance is good; the invention provides a high-strength heat-resistant aluminum alloy containing Ce-Mg, and by adding Ce near eutectic components, nanoscale Al with good thermal stability is formed in the alloy11Ce3The net-shaped skeleton is rigid, so that the interface bonding strength and the creep resistance of the alloy are improved. By adding Mg element, the high-temperature solid solution strengthening effect is exerted, the strengthening effect in high-temperature service is achieved, and the high-temperature strength performance of the alloy is further improved. The alloy has the advantages of good casting performance, simple preparation process, low process requirement, no need of heat treatment and low cost. By adopting a liquid nitrogen cooling and rapid solidification method, on one hand, the solid solubility of Mg in an Al matrix is improved, and on the other hand, the size of primary Al-Ce phase particles and the size and the spacing of eutectic Al-Ce photo layers can be effectively refined.
The Ce is added in a range of 8.0-12.0%, and the range is selected for the purpose of: one to improve castability; secondly, enough Ce can form enough Al11Ce3 eutectic phase with rigid network structure. The network can be maintained near the eutectic temperature without spheroidization, coarsening, or growth. The rigid net structure effectively improves the interface bonding strength and creep resistance of the alloy and inhibits the microcrack expansion between grain boundaries. Meanwhile, Ce can effectively reduce the viscosity of the aluminum solution, so that the alloy has good casting performance and good fluidity and can form relatively complex castings. The addition range of Mg is 4.0-8.0%, and the addition of Mg does not cause the change of Al-Ce intermetallic compound, but causes the lattice distortion of aluminum matrix, thereby generating solid solution strengthening effect in the matrix and improving the yield strength of the alloy. When the alloy is in service at high temperature, the yield strength is not reduced but increased along with the uniform diffusion of Mg element. The Ce-Mg-containing high-strength heat-resistant aluminum alloy is mainly characterized by a primary Al-Ce phase, an Al-Mg phase and an Al-Ce eutectic phase; wherein the primary Al-Ce phase is distributed in submicron block shape, and the width of the lamella of the Al-Ce eutectic phase is between 50 and 100 nm. The yield strength of the Ce-Mg-containing high-strength heat-resistant aluminum alloy at room temperature is 180-210 MPa; the yield strength of the Ce-Mg-containing high-strength heat-resistant aluminum alloy after being exposed for 1000 hours at 400 ℃ is 230MPa to 260 MPa. When the alloy is in service at high temperature, the rigid grid of Al11Ce3 is not damaged, and simultaneously, the rigid grid is uniformly diffused along with the solid solution of Mg element, so that the strength of the alloy is improved, and the problem of sharp reduction of the strength performance caused by the growth of strengthening phase particles at high temperature in the traditional aluminum alloy is solved.
Ce is added in Al-20Ce intermediate alloy, and the purity of the intermediate alloy is more than 99.5 percent. The purity of the intermediate alloy is more than 99.5%, and the prepared aluminum alloy has better effect. The purity of Al is more than 99.9%. The purity of Al is more than 99.9%, and the prepared aluminum alloy has better effect. The purity of Mg is more than 99.9 percent. The purity of Mg is more than 99.9 percent, and the prepared aluminum alloy has better effect. Optionally, 2/3 for the total amount of alloy melt being the capacity of the crucible is configured. Optionally, the wall thickness of the copper die is controlled to be 10-15mm, so that the copper die can be rapidly solidified into a casting. Optionally, the flow of the argon gas is controlled to be 0.45-0.60 m3In terms of hours. During pouring, the flow of argon is controlled to be 0.45-0.60 m 3/h, and the prepared aluminum alloy has better effect.
As shown in figure 1:
as can be seen from the figure, Al11Ce3The width of the slats of the eutectic phase was about 75 nm.
As shown in fig. 2:
as can be seen from the figure, Al11Ce3The slab width of the eutectic phase was not substantially increased, about 82 nm. The rigid net structure with good thermal stability effectively improves the interface bonding strength and creep resistance of the alloy, inhibits the microcrack expansion between grain boundaries, and improves the high-temperature strength of the alloy. In addition, under the condition of long-time service at high temperature, the Mg element is dissolved and gradually diffused uniformly, so that the strength of the alloy can be obvious, and the problem of rapid reduction of the strength performance of the traditional aluminum alloy caused by the growth of strengthening phase particles at high temperature is solved.
The above description is only an example of the present invention and common general knowledge of known features in the schemes is not described herein. It should be noted that, for those skilled in the art, without departing from the principle of the present invention, several variations and modifications can be made, which should also be regarded as the protection scope of the present invention, and these do not affect the effect of the implementation of the present invention and the practicability of the patent. The scope of the claims of the present application shall be determined by the contents of the claims, and the description of the embodiments and the like in the specification shall be used to explain the contents of the claims.
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