CN114015917A

CN114015917A - Si, Mg and Zr microalloyed AlCuMn heat-resistant aluminum alloy and heat treatment process

Info

Publication number: CN114015917A
Application number: CN202111218669.4A
Authority: CN
Inventors: 文胜平; 吴美娴; 吴晓蓝; 魏午; 高坤元; 黄晖; 聂祚仁
Original assignee: Beijing University of Technology
Current assignee: Beijing University of Technology
Priority date: 2021-10-19
Filing date: 2021-10-19
Publication date: 2022-02-08
Anticipated expiration: 2041-10-19
Also published as: CN114015917B

Abstract

A Si, Mg and Zr microalloyed AlCuMn heat-resistant aluminum alloy and a heat treatment process belong to the technical field of heat-resistant alloy materials. Alloy components: 4 to 5.6 percent of Cu, 0 to 0.35 percent of Mg, 0.2 to 0.4 percent of Mn, 0 to 0.3 percent of Zr, 0 to 0.3 percent of Si, and the balance of high-purity aluminum. According to the invention, Si, Mg and Zr microalloying and different heat treatment processes are adopted, so that the thermal stability of the alloy is improved, the alloy has higher strength under long-time thermal exposure at 225-325 ℃, and good thermal stability is maintained.

Description

Si, Mg and Zr microalloyed AlCuMn heat-resistant aluminum alloy and heat treatment process

Technical Field

The invention belongs to the technical field of alloy materials, and particularly relates to a preparation method of a microalloyed heat-resistant alloy and a heat treatment process thereof.

Technical Field

Along with the wider application of the aluminum alloy in the fields of aerospace, transportation, weapon equipment industry and the like, the requirements on some aluminum alloys with special properties are higher and higher, such as high-temperature heat-resistant aluminum alloys. At present, microalloying is used as an important means for optimizing the components of the aluminum alloy, and aims to realize the optimization of the microstructure of the alloy by adding trace elements, so that the mechanical property of the alloy material is obviously improved, and therefore the microalloying is continuously paid attention and developed in the chemical and industrial fields.

Al-Cu-Mg series alloy is a typical heat-treatable strengthened aluminum alloy, is widely applied to the fields of aerospace, civil industry and the like for a long time, and particularly plays an important role in the aerospace industry. Mg is used as a main element of the traditional heat-resistant alloy AlCuMg, and can obviously improve the strength and heat resistance of the AlCu alloy, but generally, the alloy is generally used in a working environment below 130-140 ℃, and when the working temperature exceeds 150 ℃, a strengthening phase in a matrix can be coarsened rapidly, so that the performance of the alloy is greatly reduced.

Mn and Zr are two elements commonly used as microalloying elements. Sc has been recognized as the best microalloying element, but its development is limited by its expensive price, and Zr has physical properties similar to Sc and is easy to form L1 with Al₂An AlxM intermetallic compound having a structure, so that usually a part of Zr is added to a high-temperature heat-resistant aluminum alloy to form Al₃Sc-like L1₂Structural Al₃The Zr metastable phase has low mismatching degree and is difficult to be converted into a stable phase from a metastable transition phase, thereby improving the high-temperature heat resistance of the alloy. Recent researches on Al-Cu-Mn-Zr alloy by scholars show that Mn and Zr are added into the Al-Cu alloy at the same time, the heat-resistant temperature of the alloy can be increased to 350 ℃, and the researches show that Mn can effectively stabilize a semi-coherent interface and Zr can effectively stabilize a coherent interface because Mn and Zr are precipitated at a theta'/matrix interface, so that Mn and Zr can be combined to reduce thermodynamic driving force, slow down coarsening kinetics of precipitated phases and slow down a coarsening process of the precipitated phases at high temperature. Although the addition of Mn and Zr micro-alloying elements in Al-Cu alloy makes the alloy have good performanceThe alloy has good heat resistance, but the hardness value of the alloy is lower no matter at low temperature or high temperature, and is about 100-110 Hv.

Si is usually used as an impurity element to control the content, but after a small amount of Si is added into Al-Cu-Mg alloy with high Cu/Mg ratio, finer and more dispersed phases are precipitated in the alloy structure in an artificial aging state, and a small amount of Q phase is compositely precipitated, so that the aging hardness of the alloy is improved. A plurality of researches show that the aging response speed of the Al-Cu-Mg alloy can be obviously improved by adding a small amount of Si, and simultaneously, precipitated phases in a matrix are refined and uniformly distributed, so that the mechanical property of the alloy is improved. However, Si has a problem that it does not greatly contribute to the long-term heat resistance of the alloy at a relatively high temperature.

Therefore, based on the technical background, the addition of Mg can improve the strength and the thermal stability of the alloy, Si can further improve the peak aging hardness of the alloy on the basis, and Zr can keep good stability of the alloy at higher temperature. The Mg and Zr composite added alloy has higher strength and superior thermal stability under the working condition of more than 225 ℃ through a unique heat treatment process, and the problem that the alloy has good thermal stability but low strength at higher temperature is solved. The invention exerts different advantages through element composite addition and a unique heat treatment process, so that the alloy has low-temperature and high-temperature applications.

Disclosure of Invention

The invention aims to prepare the AlCuMgMnZrSi heat-resistant alloy with better heat resistance by adding the microalloying elements of Si, Mg and Zr, and further improve the heat resistance of the alloy by a unique heat treatment process.

The AlCuMgMnZrSi heat-resistant alloy is characterized in that Si, Mg and Zr microalloying elements are added into an AlCuMn alloy matrix, wherein the weight percentage of each alloying element in the AlCuMgMnZrSi alloy is as follows: 4 to 5.6 percent of Cu, 0 to 0.35 percent of Mg, 0.2 to 0.4 percent of Mn, 0 to 0.3 percent of Zr, 0 to 0.3 percent of Si, and the balance of aluminum and inevitable impurities with the content of not more than 0.2 percent.

The preparation method of the heat-resistant alloy is characterized by comprising the following steps of: firstly putting high-purity aluminum into a graphite crucible, heating and melting the high-purity aluminum in a high-temperature melting furnace at 800 +/-5 ℃, then adding Al-Cu, Al-Mn, Al-Si and Al-Zr intermediate alloys, then adding pure Mg, wrapping and adding the pure Mg by using aluminum foil to reduce the burning loss of the Mg when adding the pure Mg, fully stirring the mixture, and after the mixture is fully melted, adding C₂Cl₆Degassing, stirring, keeping the temperature and standing, then casting by using an iron mold to obtain a cast ingot, and finally performing different heat treatment processes according to different working conditions during use to obtain the alloy material;

different heat treatment processes are carried out according to different working conditions during use, and the method specifically comprises the following steps:

(1) firstly, carrying out solution treatment at 520-540 ℃, heating for 5-7 h from room temperature, preserving heat for 6-10 h, and then carrying out water quenching to room temperature within 10 seconds.

(2) And (3) carrying out aging treatment of different systems on the solid solution alloy according to different use temperatures. A. For the working condition of using at the temperature below 200 ℃, the solid solution alloy is placed at the temperature of 170-180 ℃ for 20-24 hours to reach the peak aging.

B. For the working condition of using at the temperature of more than 200 ℃, the solid solution alloy is placed at the equal temperature of 170-180 ℃ for 20-24 hours to reach the peak aging, and then placed in a heat treatment furnace at the temperature of 310-325 ℃ for 15-30 min.

C. For the working condition of using at the temperature of more than 200 ℃, the solid solution alloy is isothermally placed at the temperature of 200-225 ℃ for 3-24 hours to reach the peak aging.

According to the invention, through the addition of Si, Mg and Zr microalloying elements and the combination of a unique heat treatment process, the synergistic effect of the three elements is exerted, and the Mg and Si composite addition can not only improve the aging hardness of the alloy at a lower temperature, but also improve the thermal stability of the alloy. On the basis, by adding Zr, the alloy can keep good stability at higher temperature, the alloy strength and the thermal stability are improved, and the application temperature range of the alloy is widened. Aiming at the heat treatment mode A in the embodiment, the mechanical property of the alloy can be improved to a large extent by the composite addition of Si and Mg, and the good thermal stability can be kept under the working condition below 200 ℃; aiming at the heat treatment mode B in the embodiment, the synergistic effect of three elements of Si, Mg and Zr can be simultaneously exerted under the heat treatment system, and the defect that the Si element is under the working condition of more than 200 ℃ is overcome. Compared with other heat treatment systems, the hardness value of the alloy is obviously higher than that of the alloy under the long-time heat exposure at 225 ℃ in the heat treatment mode C in the embodiment, and the heat treatment mode C is the optimal one of the heat treatment modes applied to the working condition of more than 200 ℃.

Description of the drawings:

FIG. 1 shows the long-term aging hardness curve at 150 ℃ after the peak aging of the alloy No. 1, No. 2, No. 3 and No. 4 at 150 ℃.

FIG. 2 is a hardness curve of alloy No. 3 and 4 after peak aging at 175 ℃ and long time aging at 175 ℃.

The alloy shown in figure 3-1:1# and 4# is subjected to peak aging at 175 ℃ and then has tensile strength at room temperature, 200 ℃, 250 ℃ and 300 ℃.

The yield strength of the alloy shown in the figure 3-2:1# and 4# after being rolled and subjected to peak aging at 175 ℃ at room temperature, 200 ℃, 250 ℃ and 300 ℃.

FIG. 3-3 is a graph showing elongation at room temperature, 200 ℃, 250 ℃ and 300 ℃ after alloy No. 1 and 4 are rolled and subjected to peak aging at 175 ℃.

FIG. 4 is a 225 ℃ long-time heat exposure hardness curve of

alloy #

1, 2, 3 and 4 after peak aging at 175 ℃.

FIG. 5 is a 275 ℃ long-time heat exposure hardness curve of

alloy #

1, 2, 3 and 4 after peak aging at 175 ℃.

FIG. 6 is a graph showing long-term hardness curves of alloys # 1, # 2, # 3 and # 4 after peak aging at 175 ℃ and after 325 ℃.

FIG. 7 is a graph showing the long term thermal exposure hardness at 225 ℃ after peak aging at 175 ℃ for alloys # 1, # 2, # 3, and # 4, and heat treatment at 325 ℃ for 30 min.

FIG. 8 is a 225 ℃ long-time aging hardness curve after 225 ℃ peak aging of 1#, 2#, 3#, and 4# alloys.

The specific implementation mode is as follows:

the present invention will be further illustrated with reference to the following examples, but the present invention is not limited to the following examples.

The AlCuMgMnZrSi alloy comprises the following components in percentage by weight: 4 to 5.6 percent of Cu, 0 to 0.35 percent of Mg, 0.2 to 0.4 percent of Mn, 0 to 0.3 percent of Zr, 0 to 0.3 percent of Si, and the balance of aluminum and inevitable impurities with the content of not more than 0.2 percent.

An ingot was prepared according to the elemental composition, and then subjected to the following treatment.

(1) Firstly, carrying out solid solution treatment at 520-540 ℃, heating for 5-7 h from room temperature, preserving heat for 6-10 h, and then carrying out water quenching to room temperature within 10s to obtain a solid solution alloy;

(2) carrying out aging treatment of different systems on the solid solution alloy according to different use temperatures;

the solid solution alloy is subjected to isothermal aging for 20-50 h at 150-180 ℃, and the thermal stability of the alloy is detected by long-time thermal exposure at 150-325 ℃, so that the interaction between metal elements is proved to realize the thermal stability.

A. Aiming at the working conditions below 200 ℃: on the basis of the step (1), after the solid solution alloy is placed at the temperature of 150-180 ℃ for 20-24 hours at the same temperature to reach peak aging, the alloy is subjected to long-time heat exposure at the temperature of 150-175 ℃, and the long-time heat stability and the high-temperature strength of the alloy are detected.

B. And (2) aiming at the working condition of more than 200 ℃, on the basis of the step (1), placing the solid solution alloy at 170-180 ℃ for 20-24 h at equal temperature to reach peak aging, then placing the alloy in a heat treatment furnace at 310-325 ℃ for 15-30 min, finally, carrying out long-time heat exposure at 225 ℃, and detecting the long-time heat stability and strength of the alloy at the temperature.

C. And (2) aiming at the working condition of more than 200 ℃, on the basis of the step (1), after the solid solution alloy is placed at 225 ℃ for 3-24 hours to reach the peak value, the alloy is subjected to long-time thermal exposure at 225 ℃, and the long-time thermal stability and strength of the alloy at the temperature are detected.

Example 1: the alloy ingot is prepared by adopting graphite crucible smelting and iron mold casting, and the raw materials are high-purity aluminum, pure magnesium, Al-50% Cu, Al-10% Mn, Al-24% Si and Al-10% Zr master alloy. Firstly putting high-purity aluminum into a graphite crucible, heating and melting the high-purity aluminum in a high-temperature melting furnace at 800 +/-5 ℃, then adding intermediate alloys of Al-50% of Cu, Al-10% of Mn, Al-24% of Si and Al-10% of Zr, wrapping and adding the intermediate alloys by using aluminum foil when adding pure Mg to reduce the burning loss of Mg, fully stirring the intermediate alloys, and after the intermediate alloys are fully melted, adding C₂Cl₆Degassing, stirring, keeping the temperature and standing, and then casting by using an iron mold to obtain a cast ingot. Four alloy materials of different compositions were prepared and the actual compositions of the alloys were obtained by XRF testing, as shown in table 1:

table 1: XRF measured composition table of alloy

Example 2 the 1#, 2#, 3#, 4# as-cast alloys of example 1 were subjected to solution treatment by raising the temperature from room temperature to 540 ℃ and keeping the temperature for 7 hours, then water-quenched to room temperature within 10 seconds, isothermally aged at 150 ℃ to the peak, and then aged at 150 ℃ for a long time to obtain aged hardness curves of the four alloys at the temperature, as shown in FIG. 1. As can be seen from the graph, at this temperature, comparing alloy # 1 with alloy # 3, after 768 hours, the hardness value of alloy # 1 begins to drop rapidly, while alloy # 3 remains stable. Compared with 3# and 4# alloys, the hardness value of the 4# alloy is always remarkably higher than that of the 3# alloy, which shows that the aging hardness and the thermal stability of the alloy can be remarkably improved by the composite addition of Si and Mg at a lower temperature. Comparing the 2# and 3# alloys, it can be seen that Zr does not work at lower temperatures.

Example 3# 3 and # 4 as-cast alloys in example 1 were subjected to solution treatment by raising the temperature from room temperature to 540 ℃ for 7 hours, then water-quenched to room temperature within 10 seconds, isothermally aged at 175 ℃ until the peak was reached, and further aged at 175 ℃ for a long time to obtain aged hardness curves of both alloys at the temperatures, as shown in FIG. 2. It can be seen from the figure that the hardness value of the 4# alloy is always significantly higher than that of the 3# alloy during long-term aging, which shows that the aging strengthening effect of Si is also very significant at the temperature.

Example 4 the alloys # 1 and # 4 of example 1 were homogenized. The specific method comprises the steps of heating the temperature from room temperature for 2-3 hours to 490 +/-10 ℃, and preserving the temperature for 6-7 hours at the temperature. Then the homogenized alloy is subjected to heat preservation at the temperature of 450 +/-10 ℃, and then is rolled, and the deformation amount is 70-90%. And then, after the rolled alloy is subjected to heat treatment at 170-180 ℃ for 20-24 h to reach peak aging, the rolled alloy is subjected to room temperature and high temperature stretching at room temperature, 200 ℃, 250 ℃ and 300 ℃ respectively to obtain the tensile strength, yield strength and elongation of the two alloys at the temperature, as shown in figures 3-1, 3-2 and 3-3. As can be seen, the tensile strength and yield strength of alloy # 4 after peak aging at 175 ℃ are significantly higher than those of alloy # 1 at four temperatures, but the difference between the tensile strength and yield strength gradually decreases with increasing temperature. It is shown that the strengthening effect gradually decreases with the increase in temperature by the addition of Si and Mg. Comparing the elongation of the two alloys, the elongation of the alloy No. 1 is obviously higher than that of the alloy No. 4 except at 250 ℃, which shows that the addition of Si and Mg can reduce the elongation of the alloy to a certain extent.

Example 5 the 1#, 2#, 3#, and 4# as-cast alloys of example 1 were subjected to solution treatment by raising the temperature from room temperature to 540 ℃ and maintaining the temperature for 7 hours, then water-quenched to room temperature within 10 seconds, isothermally aged at 175 ℃ to a peak value, and then aged at 225 ℃ for a long time from 0min to obtain aged hardness curves of the four alloys at the temperature, as shown in FIG. 4. As can be seen from the figure, the hardness values of the four alloys are reduced along with the increase of the heat exposure time, and compared with the four alloys, the hardness value of the 3# alloy is obviously higher than that of the 1# alloy in the whole heat exposure process, the hardness value of the 4# alloy with Si added on the basis of the 3# alloy is obviously higher than that of the 3# alloy in the early stage, and the hardness value of the later stage is also at a higher level. The hardness value of the 3# alloy added with Zr is always higher than that of the 2# alloy without Zr, which shows that Mg can obviously improve the hardness and the thermal stability of the alloy, Si can obviously improve the aging hardness of the alloy in the early stage on the basis, Zr can further improve the long-time thermal stability of the alloy, and the alloy added with Si, Mg and Zr has the best thermal exposure effect at 225 ℃.

Example 6: as-cast alloys # 1, # 2, # 3 and # 4 in example 1 were subjected to solution treatment of raising the temperature from room temperature to 540 ℃ for 7 hours, then water-quenched within 10 seconds to room temperature, isothermally aged at 175 ℃ to a peak, and then thermally exposed at 275 ℃ for a long time to obtain aged hardness curves of the four alloys at the temperatures, as shown in FIG. 5. As can be seen from the figure, the 3# alloy hardness value is always significantly higher than the 1# alloy, which shows that the addition of Mg can significantly improve the aging hardness of the alloy and maintain good thermal stability. The early-stage hardness value of the 4# alloy added with Si is obviously higher than that of the other three alloys, the later-stage hardness value is obviously reduced and is almost consistent with that of the 1# alloy and the 2# alloy, which shows that the early-stage aging hardness of the alloy can be obviously improved by Si, but the later-stage thermal stability of the alloy is not large, and the hardness value of the 4# alloy in the later stage is lower than that of the 3# alloy due to the addition of Si. Compared with 2# and 3# alloys, the hardness value of the 3# alloy added with Zr is higher than that of the 2# alloy after 1h, which shows that the Zr has obvious effect at higher temperature and can effectively ensure the long-time thermal stability of the alloy.

Example 7 the 1#, 2#, 3#, and 4# as-cast alloys of example 1 were subjected to solution treatment by raising the temperature from room temperature for 6 hours to 540 ℃ and maintaining the temperature for 7 hours, then water-quenched to room temperature within 10 seconds, isothermally aged at 175 ℃ to a peak, and then heat-exposed at 325 ℃ for a long time to obtain aged hardness curves of the four alloys at the temperatures, as shown in FIG. 6. As can be seen from the figure, the hardness values of the first four alloys in 1h are all rapidly reduced, and the 4# alloy hardness value is slightly higher than those of the other three alloys, but is not obvious, which indicates that the early age hardening effect of Si is not obvious at higher temperature, and the later 4# alloy hardness value is slightly lower than that of the 3# alloy due to the addition of Si. After 1h of heat exposure, the hardness values of the alloys 1#, 3# and 4# and particularly the alloy 3# change relatively gently, while the hardness value of the alloy 2# decreases significantly, and is significantly lower than that of the alloys 1#, 3# and 4# respectively. It is shown that at higher temperatures, Zr has a more significant effect on improving the thermal stability of the alloy. Comparing the alloy No. 1 with the alloy No. 3, the hardness value of the alloy No. 1 slightly decreases after 192h, while the hardness value of the alloy No. 3 hardly changes, which shows that Mg can keep good thermal stability of the alloy at the temperature.

Example 8 the 1#, 2#, 3#, 4# as-cast alloys of example 1 were subjected to solution treatment by raising the temperature from room temperature for 6h to 540 ℃ and maintaining the temperature for 7h, then water quenched within 10s to room temperature, isothermally aged at 175 ℃ to a peak value, then heat treated at 325 ℃ for 30min, and finally heat exposed at 225 ℃ for a long time to obtain aged hardness curves of the four alloys at the temperature, as shown in FIG. 7. It can be seen from the figure that after the heat treatment system of reheating exposure after low-temperature and high-temperature treatment, the change of the aged hardness curve of the four alloys is obviously different from that of other heat treatment systems, the hardness curves of 2#, 3# and 4# alloys are consistent, the hardness value is rapidly reduced after the high-temperature heat treatment at 325 ℃, but the hardness value is hardly changed in the first 200h of 225 ℃ heat exposure, the hardness value is reduced to a certain degree and tends to be gentle after 200h, and after the hardness value of the 1# alloy is rapidly reduced, the hardness value is basically kept unchanged at the later stage but is always at a lower level. In the whole heat exposure process, the 4# alloy hardness value is higher than the other two alloys all the time, and the effect of hardness value improvement is most obvious in the first 200h, which shows that the synergistic effect of Si, Mg and Zr can be exerted under the heat treatment system, the hardness value of the alloy at the early stage is obviously increased by adding Si, the hardening level of the alloy can be further improved by Mg, and good heat stability is kept, the alloy is different from other heat treatment systems by adding Zr, the hardness value of the alloy at the later stage is not rapidly reduced even if Si is added, and the heat stability of the alloy is improved. Compared with the 2# and 3# alloys, the hardness values of the first 200h are almost the same, and after 200h, the hardness value of the 3# alloy is slightly higher than that of the 2# alloy, which shows that Zr has the effect of improving the thermal stability after a longer time at the temperature.

Example 9: the 1#, 2#, 3#, and 4# as-cast alloys of example 1 were subjected to solution treatment by raising the temperature from room temperature to 540 ℃ and keeping the temperature for 7 hours, then water-quenched within 10 seconds to room temperature, aged at 225 ℃ to a peak, and then subjected to long-term heat exposure at 225 ℃ to obtain aged hardness curves of the four alloys at the temperatures, as shown in fig. 8. As can be seen from the figure, the hardness values of the 2# and 3# alloys at other time points were almost identical except for the peak hardness under the heat treatment schedule, indicating that Zr did not play a significant role in the process. The hardness value of the 4# alloy is not obviously increased at the early stage, which indicates that the direct heat exposure treatment after solid solution can not play the effect of age hardening of Si, and the hardness value of the alloy at the later stage is reduced due to the addition of Si. Comparing the 1# and 3# alloys, the 3# alloy hardness value is significantly higher than the 1# alloy. Although Si and Zr do not have obvious effect under the heat treatment system, Mg has obvious effect on improving the strength and the heat stability of the alloy, compared with other heat treatment systems, the hardness value of the alloy is obviously higher than that under other heat treatment systems under the long-time heat exposure of 225 ℃, under the heat exposure time of 3072h, the hardness value of the alloy 1 is about 113Hv, the hardness value of the alloy 2 is about 121Hv, the hardness value of the alloy 3 is about 123Hv, the hardness value of the alloy 4 is about 117Hv, and under the heat treatment system, the heat stability of the alloy is the best.

Claims

1. A microalloyed AlCuMn heat-resistant alloy of Si, Mg and Zr is characterized in that microalloyed elements of Si, Mg and Zr are added into an AlCuMn alloy matrix, wherein the weight percentage of each alloy element in the AlCuMgMnZrSi alloy is as follows: 4 to 5.6 percent of Cu, 0 to 0.35 percent of Mg, 0.2 to 0.4 percent of Mn, 0 to 0.3 percent of Zr, 0 to 0.3 percent of Si, and the balance of aluminum and inevitable impurities with the content of not more than 0.2 percent.

2. The method for preparing the Si, Mg, Zr microalloyed AlCuMn heat-resistant alloy according to claim 1, characterized in that the method comprises the following steps: firstly putting high-purity aluminum into a graphite crucible, heating and melting the high-purity aluminum in a high-temperature melting furnace at 800 +/-5 ℃, then adding intermediate alloys of Al-50% of Cu, Al-10% of Mn, Al-24% of Si and Al-10% of Zr, then adding pure Mg, wrapping and adding the pure Mg by using aluminum foil to reduce the burning loss of the Mg when adding the pure Mg, fully stirring the mixture, and after the mixture is fully melted, adding C₂Cl₆Degassing, stirring, keeping the temperature and standing, then casting by using an iron mold to obtain a cast ingot, directly performing cast state or performing deformation processing of different degrees according to the requirements of material application, and finally performing treatment by using different heat treatment processes to obtain the alloy material.

3. The method of preparing an alloy as claimed in claim 2, wherein the heat treatment process comprises the steps of:

(2) And (3) carrying out aging treatment of different systems on the solid solution alloy according to different use temperatures.

4. The alloy preparation method according to claim 3, wherein different heat treatment processes are performed according to different working conditions during use, and the method specifically comprises the following steps:

A. for the working condition of using at the temperature below 200 ℃, the solid solution alloy is placed at the temperature of 170-180 ℃ for 20-24 h to reach the peak aging;

B. for the working condition of using at the temperature of more than 200 ℃, the solid solution alloy is placed at the equal temperature of 170-180 ℃ for 20-24 hours to reach the peak aging, and then placed in a heat treatment furnace at the temperature of 310-325 ℃ for 15-30 min;

5. Use of a heat-resistant alloy prepared according to the method of claim 4 for an alloy obtained at A for operating conditions below 200 ℃ and for an alloy obtained at B and C for operating conditions above 200 ℃.