High-manganese-content Al-Cu alloy component for metal mold casting La and Ce alloying and heat treatment process of high-manganese-content Al-Cu alloy component

Abstract

The invention discloses a high-manganese-content Al-Cu alloy component for metal mold casting La and Ce alloying and a heat treatment process of the high-manganese-content Al-Cu alloy component for metal mold casting La and Ce alloying, the designed alloy component contains Mn and Mg elements, the alloy is alloyed through the La or Ce element, alpha-Al grain refinement can be achieved, the effect of the Mn element can be fully achieved, segregation is reduced, and the hot crack tendency is restrained; and the structure uniformity of alloy ingots or castings is improved. The designed as-cast alloy is subjected to solution treatment and graded aging treatment, the tensile strength of an obtained final sample is not lower than 552 MPa, and the elongation is not lower than 7.2%. Different from refining of alpha-Al grains by adding a refiner, a nucleating agent and the like to generate particles in an aluminum melt to promote nucleation, grain refinement is realized through component design under general solidification technical conditions, and the smelting process and the casting process are simplified.

Description

Technical Field

[0001] The present invention relates to the field of cast aluminum alloys, and in particular to a solidification technology capable of controlling casting defects of aluminum-copper alloy ingots or castings, and improving the uniformity of solidified structures and the serviceability of ingots or castings. Specifically, the present invention relates to a high-manganese aluminum-copper alloy composition for metal mold casting of lanthanum and cerium alloys and a heat treatment process thereof. Background Art

[0002] Cast aluminum alloys, especially those with high strength, excellent wear resistance and corrosion resistance, are subject to growing market demand. Improving the performance of existing cast aluminum alloys and developing new series of alloys to meet diverse application needs remains an important topic. Aluminum (Al)-copper (Cu) casting alloys, as an important aluminum alloy, have received extensive attention from academia and industry due to their good mechanical properties. In particular, this type of alloy often exhibits extremely excellent tensile strength and creep resistance in the temperature range of 200 ℃~350 ℃, which can meet the service requirements of aerospace parts and realize the replacement of "titanium" with "aluminum". In recent years, the demand for lightweight equipment in the automotive field, medical equipment and wind power equipment has gradually increased, which has promoted the development and application of cast aluminum alloys for large load-bearing structural parts.

[0003] Over the years, high-strength Al-Cu casting alloys with a Cu content of 4.0 ~6.0 wt.% Cu have been used in many structural parts to replace forging with casting, steel with aluminum, and integral casting, achieving good service results. However, since its liquid molding process is mainly sand casting, it is difficult to obtain high-quality ingots or castings through metal mold casting or investment casting. More importantly, in terms of strength index, the tensile strength of the same Al-Cu casting alloy using sand casting can only reach 60% ~ 80% of that of the metal mold; and in terms of plasticity performance index, the elongation of the alloy can only reach 22% ~ 44% of that of the metal mold casting. These defects significantly weaken its advantages compared with ordinary aluminum alloys. The difficulty of metal mold casting Al-Cu alloy lies in its wide crystallization range (633 ℃ ~ 544 ℃), large solidification shrinkage, and mushy solidification characteristics. The casting properties of the alloy, such as fluidity, thermal cracking resistance and airtightness, are poor, and the wall thickness sensitivity is large, which is prone to casting defects such as segregation and thermal cracking.

[0004] Rare earth elements are widely used in various aluminum alloys because of their unique properties, which can improve the alloy casting structure, achieve grain refinement, change the solidification characteristics of the alloy, thereby reducing segregation and inhibiting the tendency of hot cracking. With the continuous development of rare earth alloying theory, it will become a trend to study the role of single rare earth elements in aluminum alloys. On the other hand, manganese (Mn) is one of the common alloying elements of Al-Cu alloys. A small amount of Mn can play a solid solution strengthening role in the α-Al phase of the alloy, thereby improving the strength of α-Al and improving the hot cracking resistance of the alloy. On the other hand, Mn will also form a composite phase with other elements in the alloy (such as magnesium (Mg)) to reduce the number of Al2Cu phases, reduce grain boundary segregation, and improve the strength of the alloy, which is also beneficial to improve the mechanical properties of the alloy. However, it can be seen from the public literature that the range of Mn content is usually relatively low, especially in cast Al-Cu alloys, which is often less than 0.4 wt.%. If more Mn is added, it is easy to cause the high-temperature mechanical properties of the alloy to decrease. This greatly limits the full play of the performance of the Mn element. In order to break through the composition limitation of Mn element and cooperate with the effect of Mg element, this alloying method not only improves the performance of aluminum alloy, but also opens up new directions for the innovation and application of future materials. Summary of the invention

[0005] Purpose of the invention: The purpose of the present invention is to provide a high manganese content Al-Cu alloy composition and its heat treatment process for metal mold casting La, Ce alloying, which can achieve α-Al grain refinement, cooperate with the effect of Mg element, reduce segregation and inhibit hot cracking tendency, and improve the uniformity of the structure of alloy ingots or castings. Different from the refinement of α-Al grains by adding refiners, inoculants, etc. to promote nucleation from particles generated in the aluminum melt, the present invention is a method of achieving grain refinement through component design and general solidification technology conditions, simplifying the smelting process and casting process. The designed cast alloy is subjected to solution treatment and graded aging treatment, and the final sample obtained has a tensile strength of not less than 552 MPa and an elongation of not less than 7.2%.

[0006] Technical solution: A high manganese content Al-Cu alloy composition for metal mold casting La, Ce alloying and its heat treatment process, through the design of Mn and Mg elements, give full play to the role of Mn element and cooperate with the alloying effect of La and Ce elements, reduce segregation and inhibit hot cracking tendency, and improve the organizational uniformity of alloy ingots or castings; specifically includes the following steps: Step (1) using industrial pure aluminum, Al20Cu (Al-20 wt.% Cu) master alloy, Al20Mn (Al-20 wt.% Mn) master alloy, Al20Mg (Al-20 wt.% Mg) master alloy, Al10TiV (Al-10 wt.% Ti-1.0 wt.% V) master alloy and Al10Zr5B (Al-10 wt.% Zr-1.0 wt.% B) master alloy as raw materials, adding alloying elements using Al10La (Al-10 wt.% La) and Al10Ce (Al-10 wt.% Ce) master alloy as raw materials, calculating and weighing each raw material that meets the design composition; The alloy composition range is Cu: 4.60wt.% -6.60wt.%, Mn: 0.40wt.% -0.95wt.%, Mg: 0.20wt.% -0.32wt.%, the total amount of Ti and Zr elements does not exceed 0.40wt.%, the total amount of V and B does not exceed 0.3wt.%, the total content of other impurities does not exceed 0.15wt.%, and the content of a single impurity component does not exceed 0.02wt.%, and the balance is Al; in addition, alloying elements La or Ce elements are added, and the addition amount is 0.10wt.% -0.30wt.% of the weight of the alloy to be prepared; Step (2) using a general smelting technology, placing the raw materials in step (1) in a graphite crucible in sequence according to the general smelting technical specifications to prepare an Al-Cu alloy, the process comprising heating, melting, adding materials to supplement the element content decreased due to burning, adding alloying elements La or Ce, degassing, refining, and heat preservation to obtain an alloy melt; Step (3) heating the metal casting mold with a cylindrical and square inner cavity to 220°C-350°C; Step (4) using a general casting technology to perform metal mold gravity casting and metal mold low-pressure casting, introducing the melt in step (2) into the casting mold of step (3) by selecting a melt injection method according to different casting processes, and then cooling naturally or using a forced cooling method to obtain an ingot or casting, and then performing a solution treatment and a graded aging treatment; Step (5) solution treatment: placing the ingot or casting in step (4) into a muffle furnace for preheating and heat preservation at a temperature range of 480°C to 580°C for a heat preservation time of 12 to 18 hours, taking out the ingot or casting and placing it in an environment where a cooling rate of 3000°C / h to 10000°C / h can be achieved for cooling, i.e., quenching to room temperature, and the time for transferring from the furnace to water does not exceed 10 seconds; Step (6) graded aging treatment: the cooled ingot or casting in step (5) is placed in a muffle furnace or a blast drying oven for insulation at a temperature range of 210°C-230°C for 30 minutes-45 minutes, and then the temperature is lowered (or transferred to another device) to 130°C-160°C for 8-10 hours, or lowered to 165°C-180°C for 4-6 hours, or lowered to 185°C-205°C for 2-5 hours, and then cooled in the furnace or the ingot or casting is taken out and then cooled naturally to obtain a final ingot or casting product.

[0007] As an optimization, the alloying element La added in the step (2) is added in the form of Al10La, and the alloying element Ce added is added in the form of Al10Ce.

[0008] As an optimization: the cooling means in step (4) is water cooling or air cooling.

[0009] As an optimization: the environment in which the cooling rate of 3000°C / h-10000°C / h is achieved in step (5) is water or a water-soluble quenching liquid of a high molecular polymer.

[0010] Beneficial effects: The present invention provides an Al-Cu alloy that can be used for metal mold casting. By designing an Al-Cu alloy composition with a higher Mn content, containing 4.60 wt.% to 6.60 wt.%, and alloying the alloy with La and Ce elements, the α-Al grain can be refined, segregation can be reduced, and the tendency to hot cracking can be suppressed, and the uniformity of the structure of the alloy ingot or casting can be improved. Then, the mechanical properties of the alloy can be improved through corresponding heat treatment. The designed cast alloy is subjected to solution treatment and graded aging treatment, and the tensile strength of the final sample obtained is not less than 552 MPa and the elongation is not less than 7.2%. The present invention does not involve the discharge of waste gas, waste water, etc., and will not pollute the environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a schematic diagram of the solidification structure of Example 1 of the present invention.

[0012] Figure 2 It is a schematic diagram of the solidification structure of Example 3 of the present invention.

[0013] Figure 3 It is a schematic diagram of the solidification structure of Example 5 of the present invention.

[0014] Figure 4 It is a schematic diagram of the sample structure of Example 9 of the present invention.

[0015] Figure 5 It is a schematic diagram of the sample structure of Example 10 of the present invention.

[0016] Figure 6 It is a schematic diagram of the sample structure of Example 12 of the present invention. DETAILED DESCRIPTION

[0017] The technical solutions in the embodiments of the present invention will be described clearly and completely below so that those skilled in the art can better understand the advantages and features of the present invention, thereby making a clearer definition of the protection scope of the present invention. The embodiments described in the present invention are only a part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention. Example 1

[0018] A high manganese content Al-Cu alloy composition for metal mold casting La, Ce alloying and a heat treatment process thereof, comprising the following steps: Step (1) using industrial pure aluminum, Al20Cu, Al20Mn, Al20M, Al10TiV, Al10Zr5B, Al10La and Al10Ce master alloy as raw materials, calculating and weighing raw materials that meet the designed composition; the designed alloy composition is Cu: 4.60wt.%, Mn: 0.40wt.%, Mg: 0.20wt.%, Ti and Zr elements are 0.20wt.%, V and B elements are 0.15wt.%, the total content of other impurities does not exceed 0.15wt.%, and the content of a single impurity component does not exceed 0.02wt.%, and the balance is Al; the addition amount of alloying element La is 0.10wt.%; Step (2) using a general smelting technology, placing the raw materials in step (1) in a graphite crucible in sequence according to the general smelting technical specifications to prepare an Al-Cu alloy, the conventional process includes heating, melting, adding materials (supplementing the element content decreased due to burning and adding alloying elements La (added in the form of Al10La)), degassing, refining, and heat preservation to obtain an alloy melt; Step (3) heating the metal casting mold with a cylindrical and square inner cavity to 220° C. Step (4) using a common casting technology, pouring the material in step (2) into the casting mold in step (3), followed by natural cooling to obtain an ingot or casting, and then performing a heat treatment; Step (5) solution treatment: the ingot or casting in step (4) is placed in a muffle furnace for preheating and heat preservation at a temperature of 480°C for 12 hours, the ingot or casting is taken out and transferred to water for cooling to room temperature, and the time for transferring from the furnace to the water does not exceed 10 seconds; Step (6) graded aging treatment: the cooled ingot or casting in step (5) is placed in a muffle furnace for insulation at a temperature of 210°C. After insulation for 30 minutes, the temperature is reduced to 130°C and the insulation time is continued for 8 hours. The ingot or casting is cooled to room temperature with the furnace to obtain an ingot or casting.

[0019] Example 2 A high manganese content Al-Cu alloy composition for metal mold casting La, Ce alloying and a heat treatment process thereof, comprising the following steps: Step (1) using industrial pure aluminum, Al20Cu, Al20Mn, Al20M, Al10TiV, Al10Zr5B, Al10La and Al10Ce master alloy as raw materials, calculating and weighing raw materials that meet the designed composition; the designed alloy composition range is Cu: 6.60 wt.%, Mn: 0.95 wt.%, Mg: 0.32 wt.%, Ti and Zr elements are 0.10 wt.%, V and B elements are 0.05 wt.%, the total content of other impurities does not exceed 0.15 wt.%, and the content of a single impurity component does not exceed 0.02 wt.%, and the balance is Al; the addition amount of alloying element La is 0.30 wt.%; Step (2) using a general smelting technology, placing the raw materials in step (1) in a graphite crucible in sequence according to the general smelting technical specifications to prepare an Al-Cu alloy, the conventional process includes heating, melting, adding materials (supplementing the element content decreased due to burning and adding alloying elements La (added in the form of Al10La)), degassing, refining, and heat preservation to obtain an alloy melt; Step (3) heating the metal casting mold with a cylindrical and square inner cavity to 350° C. Step (4) using a general casting technology, pouring the melt in step (2) into the casting mold in step (3), then water cooling to room temperature to obtain an ingot or casting, and performing heat treatment; Step (5) solution treatment: the ingot or casting in step (4) is placed in a muffle furnace for preheating and heat preservation, with a temperature range of 580°C and a heat preservation time of 18 hours. The ingot or casting is taken out and transferred to water for cooling to room temperature. The time for transferring from the furnace to the water does not exceed 10 s. Step (6) graded aging treatment: the cooled ingot or casting in step (5) is placed in a muffle furnace or a forced air drying oven for insulation at a temperature of 230°C. After the insulation time is 45 minutes, the temperature is reduced to 160°C and the insulation time is continued for 10 hours. The ingot or casting product is cooled to room temperature with the furnace to obtain a final ingot or casting product.

[0020] Example 3 A high manganese content Al-Cu alloy composition for metal mold casting La, Ce alloying and a heat treatment process thereof, comprising the following steps: Step (1) using industrial pure aluminum, Al20Cu, Al20Mn, Al20M, Al10TiV, Al10Zr5B, Al10La and Al10Ce master alloy as raw materials, calculating and weighing raw materials that meet the designed composition; the designed alloy composition range is Cu: 5.60 wt.%, Mn: 0.65 wt.%, Mg: 0.26 wt.%, the amount of Ti and Zr elements is 0.10 wt.%, the amount of V and B elements is 0.1 wt.%, the total content of other impurities does not exceed 0.15 wt.%, and the content of a single impurity component does not exceed 0.02 wt.%, and the balance is Al; the amount of alloying element La added is 0.20 wt.%; Step (2) using a general smelting technology, placing the raw materials in step (1) in a graphite crucible in sequence according to the general smelting technical specifications to prepare an Al-Cu alloy, the conventional process includes heating, melting, adding materials (supplementing the element content decreased due to burning and adding alloying elements La (added in the form of Al10La)), degassing, refining, and heat preservation to obtain an alloy melt; Step (3) heating the metal casting mold with a cylindrical and square inner cavity to 285° C. Step (4) using a general casting technology, pouring the melt in step (2) into the casting mold in step (3), then naturally cooling to room temperature to obtain an ingot or casting, and performing heat treatment; Step (5) solution treatment: the ingot or casting in step (4) is placed in a muffle furnace for preheating and heat preservation at a temperature of 530°C for 16 hours, the ingot or casting is taken out and transferred to water for cooling to room temperature, and the time for transfer from the furnace to the water does not exceed 10 seconds; Step (6) graded aging treatment: the cooled ingot or casting in step (5) is placed in a muffle furnace for insulation at a temperature of 220°C. After 40 minutes of insulation, the temperature is lowered to 145°C and the insulation is continued for 9 hours. The ingot or casting is cooled with the furnace to obtain an ingot or casting.

[0021] Example 4 A high manganese content Al-Cu alloy composition for metal mold casting La, Ce alloying and a heat treatment process thereof, comprising the following steps: Step (1) using industrial pure aluminum, Al20Cu, Al20Mn, Al20M, Al10TiV, Al10Zr5B, Al10La and Al10Ce master alloy as raw materials, calculating and weighing raw materials that meet the designed composition; the designed alloy composition is Cu: 4.60wt.%, Mn: 0.40wt.%, Mg: 0.20wt.%, Ti and Zr elements are 0.20wt.%, V and B elements are 0.15wt.%, the total content of other impurities does not exceed 0.15wt.%, and the content of a single impurity component does not exceed 0.02wt.%, and the balance is Al; the addition amount of alloying element La is 0.10wt.%; Step (2) using a general smelting technology, placing the raw materials in step (1) in a graphite crucible in sequence according to the general smelting technical specifications to prepare an Al-Cu alloy, the conventional process includes heating, melting, adding materials (supplementing the element content decreased due to burning and adding alloying elements La (added in the form of Al10La)), degassing, refining, and heat preservation to obtain an alloy melt; Step (3) heating the metal casting mold with a cylindrical and square inner cavity to 220° C. Step (4) using a common casting technology, pouring the material in step (2) into the casting mold in step (3), followed by natural cooling to obtain an ingot or casting, and then performing a heat treatment; Step (5) solution treatment: the ingot or casting in step (4) is placed in a muffle furnace for preheating and heat preservation at a temperature of 480°C for 12 hours, the ingot or casting is taken out and transferred to water for cooling to room temperature, and the time for transferring from the furnace to the water does not exceed 10 seconds; Step (6) graded aging treatment: the cooled ingot or casting in step (5) is placed in a muffle furnace for insulation at a temperature of 210°C. After insulation for 30 minutes, the temperature is reduced to 165°C and the insulation time is continued for 4 hours. The ingot or casting is cooled in the furnace or taken out and then cooled naturally to obtain an ingot or casting.

[0022] Example 5 A high manganese content Al-Cu alloy composition for metal mold casting La, Ce alloying and a heat treatment process thereof, comprising the following steps: Step (1) using industrial pure aluminum, Al20Cu, Al20Mn, Al20M, Al10TiV, Al10Zr5B, Al10La and Al10Ce master alloy as raw materials, calculating and weighing raw materials that meet the designed composition; the designed alloy composition is Cu: 4.60wt.%, Mn: 0.40wt.%, Mg: 0.20wt.%, Ti and Zr elements are 0.20wt.%, V and B elements are 0.15wt.%, the total content of other impurities does not exceed 0.15wt.%, and the content of a single impurity component does not exceed 0.02wt.%, and the balance is Al; the addition amount of alloying element La is 0.10wt.%; Step (2) using a general smelting technology, placing the raw materials in step (1) in a graphite crucible in sequence according to the general smelting technical specifications to prepare an Al-Cu alloy, the conventional process includes heating, melting, adding materials (supplementing the element content decreased due to burning and adding alloying elements La (added in the form of Al10La)), degassing, refining, and heat preservation to obtain an alloy melt; Step (3) heating the metal casting mold with a cylindrical and square inner cavity to 220° C. Step (4) using a common casting technology, pouring the material in step (2) into the casting mold in step (3), followed by natural cooling to obtain an ingot or casting, and then performing a heat treatment; Step (5) solution treatment: the ingot or casting in step (4) is placed in a muffle furnace for preheating and heat preservation at a temperature of 480°C for 12 hours, the ingot or casting is taken out and transferred to water for cooling to room temperature, and the time for transferring from the furnace to the water does not exceed 10 seconds; Step (6) graded aging treatment: the cooled ingot or casting in step (5) is placed in a muffle furnace for insulation at a temperature of 210°C. After insulation for 30 minutes, the temperature is reduced to 180°C and the insulation time is continued for 6 hours. The ingot or casting is cooled in the furnace to obtain an ingot or casting.

[0023] Example 6 A high manganese content Al-Cu alloy composition for metal mold casting La, Ce alloying and a heat treatment process thereof, comprising the following steps: Step (1) using industrial pure aluminum, Al20Cu, Al20Mn, Al20M, Al10TiV, Al10Zr5B, Al10La and Al10Ce master alloy as raw materials, calculating and weighing raw materials that meet the designed composition; the designed alloy composition is Cu: 4.60wt.%, Mn: 0.40wt.%, Mg: 0.20wt.%, Ti and Zr elements are 0.20wt.%, V and B elements are 0.15wt.%, the total content of other impurities does not exceed 0.15wt.%, and the content of a single impurity component does not exceed 0.02wt.%, and the balance is Al; the addition amount of alloying element La is 0.10wt.%; Step (2) using a general smelting technology, placing the raw materials in step (1) in a graphite crucible in sequence according to the general smelting technical specifications to prepare an Al-Cu alloy, the conventional process includes heating, melting, adding materials (supplementing the element content decreased due to burning and adding alloying elements La (added in the form of Al10La)), degassing, refining, and heat preservation to obtain an alloy melt; Step (3) heating the metal casting mold with a cylindrical and square inner cavity to 220° C. Step (4) using a common casting technology, pouring the material in step (2) into the casting mold in step (3), followed by natural cooling to obtain an ingot or casting, and then performing a heat treatment; Step (5) solution treatment: the ingot or casting in step (4) is placed in a muffle furnace for preheating and heat preservation at a temperature of 480°C for 12 hours, the ingot or casting is taken out and transferred to water for cooling to room temperature, and the time for transferring from the furnace to the water does not exceed 10 seconds; Step (6) graded aging treatment: the cooled ingot or casting in step (5) is placed in a muffle furnace for insulation at a temperature of 210°C. After insulation for 30 minutes, the temperature is reduced to 185°C and the insulation time is continued for 2 hours. The ingot or casting is taken out and then cooled naturally to obtain an ingot or casting.

[0024] Example 7 A high manganese content Al-Cu alloy composition for metal mold casting La, Ce alloying and a heat treatment process thereof, comprising the following steps: Step (1) using industrial pure aluminum, Al20Cu, Al20Mn, Al20M, Al10TiV, Al10Zr5B, Al10La and Al10Ce master alloy as raw materials, calculating and weighing raw materials that meet the designed composition; the designed alloy composition range is Cu: 6.60 wt.%, Mn: 0.95 wt.%, Mg: 0.32 wt.%, Ti and Zr elements are 0.10 wt.%, V and B elements are 0.05 wt.%, the total content of other impurities does not exceed 0.15 wt.%, and the content of a single impurity component does not exceed 0.02 wt.%, and the balance is Al; the addition amount of alloying element La is 0.30 wt.%; Step (2) using a general smelting technology, placing the raw materials in step (1) in a graphite crucible in sequence according to the general smelting technical specifications to prepare an Al-Cu alloy, the conventional process includes heating, melting, adding materials (supplementing the element content decreased due to burning and adding alloying elements La (added in the form of Al10La)), degassing, refining, and heat preservation to obtain an alloy melt; Step (3) heating the metal casting mold with a cylindrical and square inner cavity to 350° C. Step (4) using a general casting technology, pouring the melt in step (2) into the casting mold in step (3), then water cooling to room temperature to obtain an ingot or casting, and performing heat treatment; Step (5) solution treatment: the ingot or casting in step (4) is placed in a muffle furnace for preheating and heat preservation, with a temperature range of 580°C and a heat preservation time of 18 hours. The ingot or casting is taken out and transferred to water for cooling to room temperature. The time for transferring from the furnace to the water does not exceed 10 s. Step (6) graded aging treatment: the cooled ingot or casting in step (5) is placed in a muffle furnace or a forced air drying oven for insulation at a temperature of 230°C. After the insulation time is 45 minutes, the temperature is lowered to 205°C and the insulation time is continued for 5 hours. The ingot or casting product is cooled to room temperature with the furnace to obtain a final ingot or casting product.

[0025] Example 8 A high manganese content Al-Cu alloy composition for metal mold casting La, Ce alloying and a heat treatment process thereof, comprising the following steps: Step (1) using industrial pure aluminum, Al20Cu, Al20Mn, Al20M, Al10TiV, Al10Zr5B, Al10La and Al10Ce master alloy as raw materials, calculating and weighing raw materials that meet the designed composition; the designed alloy composition range is Cu: 6.60 wt.%, Mn: 0.95 wt.%, Mg: 0.32 wt.%, Ti and Zr elements are 0.10 wt.%, V and B elements are 0.05 wt.%, the total content of other impurities does not exceed 0.15 wt.%, and the content of a single impurity component does not exceed 0.02 wt.%, and the balance is Al; the addition amount of alloying element La is 0.30 wt.%; Step (2) using a general smelting technology, placing the raw materials in step (1) in a graphite crucible in sequence according to the general smelting technical specifications to prepare an Al-Cu alloy, the conventional process includes heating, melting, adding materials (supplementing the element content decreased due to burning and adding alloying elements La (added in the form of Al10La)), degassing, refining, and heat preservation to obtain an alloy melt; Step (3) heating the metal casting mold with a cylindrical and square inner cavity to 350° C. Step (4) using a general casting technology, pouring the melt in step (2) into the casting mold in step (3), then water cooling to room temperature to obtain an ingot or casting, and performing heat treatment; Step (5) solution treatment: the ingot or casting in step (4) is placed in a muffle furnace for preheating and heat preservation, with a temperature range of 580°C and a heat preservation time of 18 hours. The ingot or casting is taken out and transferred to water for cooling to room temperature. The time for transferring from the furnace to the water does not exceed 10 s. Step (6) graded aging treatment: the cooled ingot or casting in step (5) is placed in a muffle furnace or a forced air drying oven for insulation at a temperature of 230°C for 45 minutes, then the temperature is reduced to 195°C and the insulation time is continued for 3 hours. The ingot or casting is taken out and then naturally cooled to room temperature to obtain a final ingot or casting product.

[0026] Example 9 A high manganese content Al-Cu alloy composition for metal mold casting La, Ce alloying and a heat treatment process thereof, comprising the following steps: Step (1) using industrial pure aluminum, Al20Cu, Al20Mn, Al20M, Al10TiV, Al10Zr5B, Al10La and Al10Ce master alloy as raw materials, calculating and weighing raw materials that meet the designed composition; the designed alloy composition range is Cu: 5.60 wt.%, Mn: 0.65 wt.%, Mg: 0.26 wt.%, the amount of Ti and Zr elements is 0.10 wt.%, the amount of V and B elements is 0.1 wt.%, the total content of other impurities does not exceed 0.15 wt.%, and the content of a single impurity component does not exceed 0.02 wt.%, and the balance is Al; the amount of alloying element La added is 0.20 wt.%; Step (2) using a general smelting technology, placing the raw materials in step (1) in a graphite crucible in sequence according to the general smelting technical specifications to prepare an Al-Cu alloy, the conventional process includes heating, melting, adding materials (supplementing the element content decreased due to burning and adding alloying elements La (added in the form of Al10La)), degassing, refining, and heat preservation to obtain an alloy melt; Step (3) heating the metal casting mold with a cylindrical and square inner cavity to 285° C. Step (4) using a general casting technology, pouring the melt in step (2) into the casting mold in step (3), then naturally cooling to room temperature to obtain a casting, and performing heat treatment; Step (5) solution treatment: the casting in step (4) is placed in a muffle furnace for preheating and heat preservation at a temperature of 530°C for 16 hours, the casting is taken out and transferred to water for cooling to room temperature, and the time for transferring from the furnace to the water does not exceed 10 seconds; Step (6) graded aging treatment: the cooled ingot or casting in step (5) is placed in a muffle furnace for insulation at a temperature of 220°C. After 40 minutes of insulation, the temperature is lowered to 145°C and the insulation time is continued for 8 hours. The ingot or casting is then cooled to room temperature to obtain a final casting product.

[0027] Example 10 A high manganese content Al-Cu alloy composition for metal mold casting La, Ce alloying and a heat treatment process thereof, comprising the following steps: Step (1) using industrial pure aluminum, Al20Cu, Al20Mn, Al20M, Al10TiV, Al10Zr5B, Al10La and Al10Ce master alloy as raw materials, calculating and weighing raw materials that meet the designed composition; the designed alloy composition range is Cu: 5.60 wt.%, Mn: 0.65 wt.%, Mg: 0.26 wt.%, the amount of Ti and Zr elements is 0.10 wt.%, the amount of V and B elements is 0.1 wt.%, the total content of other impurities does not exceed 0.15 wt.%, and the content of a single impurity component does not exceed 0.02 wt.%, and the balance is Al; the amount of alloying element La added is 0.20 wt.%; Step (2) using a general smelting technology, placing the raw materials in step (1) in a graphite crucible in sequence according to the general smelting technical specifications to prepare an Al-Cu alloy, the conventional process includes heating, melting, adding materials (supplementing the element content decreased due to burning and adding alloying elements La (added in the form of Al10La)), degassing, refining, and heat preservation to obtain an alloy melt; Step (3) heating the metal casting mold with a cylindrical and square inner cavity to 285° C. Step (4) using a general casting technology, pouring the melt in step (2) into the casting mold in step (3), then naturally cooling to room temperature to obtain a casting, and performing heat treatment; Step (5) solution treatment: the casting in step (4) is placed in a muffle furnace for preheating and heat preservation at a temperature of 530°C for 16 hours, the casting is taken out and transferred to water for cooling to room temperature, and the time for transferring from the furnace to the water does not exceed 10 seconds; Step (6) graded aging treatment: the cooled ingot or casting in step (5) is placed in a muffle furnace for insulation at a temperature of 220°C. After 40 minutes of insulation time, the temperature is reduced to 150°C and the insulation time is continued for 6 hours. The ingot or casting is taken out and then naturally cooled to room temperature to obtain a final ingot or casting product.

[0028] Embodiment 11 A high manganese content Al-Cu alloy composition for metal mold casting La, Ce alloying and a heat treatment process thereof, comprising the following steps: Step (1) using industrial pure aluminum, Al20Cu, Al20Mn, Al20M, Al10TiV, Al10Zr5B, Al10La and Al10Ce master alloy as raw materials, calculating and weighing raw materials that meet the designed composition; the designed alloy composition range is Cu: 5.60 wt.%, Mn: 0.65 wt.%, Mg: 0.26 wt.%, the amount of Ti and Zr elements is 0.10 wt.%, the amount of V and B elements is 0.1 wt.%, the total content of other impurities does not exceed 0.15 wt.%, and the content of a single impurity component does not exceed 0.02 wt.%, and the balance is Al; the amount of alloying element La added is 0.20 wt.%; Step (2) using a general smelting technology, placing the raw materials in step (1) in a graphite crucible in sequence according to the general smelting technical specifications to prepare an Al-Cu alloy, the conventional process includes heating, melting, adding materials (supplementing the element content decreased due to burning and adding alloying elements La (added in the form of Al10La)), degassing, refining, and heat preservation to obtain an alloy melt; Step (3) heating the metal casting mold with a cylindrical and square inner cavity to 285° C. Step (4) using a general casting technology, pouring the melt in step (2) into the casting mold in step (3), then naturally cooling to room temperature to obtain an ingot or casting, and performing heat treatment; Step (5) solution treatment: the ingot or casting in step (4) is placed in a muffle furnace for preheating and heat preservation at a temperature of 530°C for 16 hours, the ingot or casting is taken out and transferred to water for cooling to room temperature, and the time for transfer from the furnace to the water does not exceed 10 seconds; Step (6) graded aging treatment: the cooled ingot or casting in step (5) is placed in a muffle furnace for insulation at a temperature range of 220°C. After 40 minutes of insulation time, the temperature is reduced to 185°C and the insulation time is continued for 4 hours. The ingot or casting is cooled to room temperature with the furnace to obtain a final ingot or casting product.

[0029] Example 12 A high manganese content Al-Cu alloy composition for metal mold casting La, Ce alloying and a heat treatment process thereof, comprising the following steps: Step (1) using industrial pure aluminum, Al20Cu, Al20Mn, Al20M, Al10TiV, Al10Zr5B, Al10La and Al10Ce master alloy as raw materials, calculating and weighing raw materials that meet the designed composition; the designed alloy composition range is Cu: 5.60 wt.%, Mn: 0.65 wt.%, Mg: 0.26 wt.%, the amount of Ti and Zr elements is 0.10 wt.%, the amount of V and B elements is 0.1 wt.%, the total content of other impurities does not exceed 0.15 wt.%, and the content of a single impurity component does not exceed 0.02 wt.%, and the balance is Al; the amount of alloying element La added is 0.20 wt.%; Step (2) using a general smelting technology, placing the raw materials in step (1) in a graphite crucible in sequence according to the general smelting technical specifications to prepare an Al-Cu alloy, the conventional process includes heating, melting, adding materials (supplementing the element content decreased due to burning and adding alloying elements La (added in the form of Al10La)), degassing, refining, and heat preservation to obtain an alloy melt; Step (3) heating the metal casting mold with a cylindrical and square inner cavity to 285° C. Step (4) using a general casting technology, pouring the melt in step (2) into the casting mold in step (3), then naturally cooling to room temperature to obtain a casting, and performing heat treatment; Step (5) solution treatment: the casting in step (4) is placed in a muffle furnace for preheating and heat preservation at a temperature of 530°C for 16 hours, the casting is taken out and transferred to water for cooling to room temperature, and the time for transferring from the furnace to the water does not exceed 10 seconds; Step (6) graded aging treatment: the cooled casting in step (5) is placed in a muffle furnace for insulation at a temperature range of 220°C. After 40 minutes of insulation time, the temperature is lowered to 205°C and the insulation time is continued for 5 hours. The ingot or casting is taken out and then naturally cooled to room temperature to obtain a casting product.

[0030] Example 13 A high manganese content Al-Cu alloy composition for metal mold casting La, Ce alloying and a heat treatment process thereof, comprising the following steps: Step (1) using industrial pure aluminum, Al20Cu, Al20Mn, Al20M, Al10TiV, Al10Zr5B, Al10La and Al10Ce master alloys as raw materials, calculating and weighing raw materials that meet the designed composition; the designed alloy composition is Cu: 4.60wt.%, Mn: 0.40wt.%, Mg: 0.20wt.%, Ti and Zr elements are 0.20wt.%, V and B elements are 0.15wt.%, the total content of other impurities does not exceed 0.15wt.%, and the content of a single impurity component does not exceed 0.02wt.%, and the balance is Al; the addition amount of alloying element Ce is 0.10wt.%; Step (2) uses a general smelting technology to sequentially place the raw materials in step (1) into a graphite crucible according to the general smelting technical specifications to prepare an Al-Cu alloy. The conventional process includes heating, melting, adding materials (supplementing the element content decreased due to burning and adding alloying element Ce (added in the form of Al10Ce)), degassing, refining, and heat preservation to obtain an alloy melt; Step (3) heating the metal casting mold with a cylindrical and square inner cavity to 220° C. Step (4) using a common casting technology, pouring the material in step (2) into the casting mold in step (3), followed by natural cooling to obtain an ingot or casting, and then performing a heat treatment; Step (5) solution treatment: the ingot or casting in step (4) is placed in a muffle furnace for preheating and heat preservation at a temperature of 510°C for 16 hours, the ingot or casting is taken out and transferred to water for cooling to room temperature, and the time for transferring from the furnace to the water does not exceed 10 seconds; Step (6) graded aging treatment: the cooled ingot or casting in step (5) is placed in a muffle furnace for insulation at a temperature of 220°C. After insulation for 45 minutes, the temperature is reduced to 140°C and the insulation time is continued for 9 hours. The ingot or casting is cooled to room temperature with the furnace to obtain a final ingot or casting product.

[0031] Embodiment 14 A high manganese content Al-Cu alloy composition for metal mold casting La, Ce alloying and a heat treatment process thereof, comprising the following steps: Step (1) using industrial pure aluminum, Al20Cu, Al20Mn, Al20M, Al10TiV, Al10Zr5B, Al10La and Al10Ce master alloy as raw materials, calculating and weighing raw materials that meet the designed composition; the designed alloy composition range is Cu: 6.60 wt.%, Mn: 0.95 wt.%, Mg: 0.32 wt.%, Ti and Zr elements are 0.10 wt.%, V and B elements are 0.05 wt.%, the total content of other impurities does not exceed 0.15 wt.%, and the content of a single impurity component does not exceed 0.02 wt.%, and the balance is Al; the addition amount of alloying element La is 0.30 wt.%; Step (2) uses a general smelting technology to sequentially place the raw materials in step (1) into a graphite crucible according to the general smelting technical specifications to prepare an Al-Cu alloy. The conventional process includes heating, melting, adding materials (supplementing the element content decreased due to burning and adding alloying element Ce (added in the form of Al10Ce)), degassing, refining, and heat preservation to obtain an alloy melt; Step (3) heating the metal casting mold with a cylindrical and square inner cavity to 350° C. Step (4) using a general casting technology, pouring the melt in step (2) into the casting mold in step (3), then water cooling to room temperature to obtain an ingot or casting, and performing heat treatment; Step (5) solution treatment: the ingot or casting in step (4) is placed in a muffle furnace for preheating and heat preservation, with a temperature range of 560°C and a heat preservation time of 12 hours. The ingot or casting is taken out and transferred to water for cooling to room temperature. The time for transferring from the furnace to the water does not exceed 10 seconds. Step (6) graded aging treatment: the cooled ingot or casting in step (5) is placed in a muffle furnace or a forced air drying oven for insulation at a temperature of 210°C. After the insulation time is 35 minutes, the temperature is reduced to 150°C and the insulation time is continued for 10 hours. The ingot or casting product is cooled to room temperature with the furnace to obtain a final ingot or casting product.

[0032] Embodiment 15 A high manganese content Al-Cu alloy composition for metal mold casting La, Ce alloying and a heat treatment process thereof, comprising the following steps: Step (1) using industrial pure aluminum, Al20Cu, Al20Mn, Al20M, Al10TiV, Al10Zr5B, Al10La and Al10Ce master alloys as raw materials, calculating and weighing raw materials that meet the designed composition; the designed alloy composition range is Cu: 5.60 wt.%, Mn: 0.65 wt.%, Mg: 0.26 wt.%, the amount of Ti and Zr elements is 0.10 wt.%, the amount of V and B elements is 0.1 wt.%, the total content of other impurities does not exceed 0.15 wt.%, and the content of a single impurity component does not exceed 0.02 wt.%, and the balance is Al; the amount of alloying element Ce added is 0.20 wt.%; Step (2) uses a general smelting technology to sequentially place the raw materials in step (1) into a graphite crucible according to the general smelting technical specifications to prepare an Al-Cu alloy. The conventional process includes heating, melting, adding materials (supplementing the element content decreased due to burning and adding alloying element Ce (added in the form of Al10Ce)), degassing, refining, and heat preservation to obtain an alloy melt; Step (3) heating the metal casting mold with a cylindrical and square inner cavity to 285° C. Step (4) using a general casting technology, pouring the melt in step (2) into the casting mold in step (3), then naturally cooling to room temperature to obtain an ingot or casting, and performing heat treatment; Step (5) solution treatment: the ingot or casting in step (4) is placed in a muffle furnace for preheating and heat preservation at a temperature of 490°C for 14 hours, the ingot or casting is taken out and transferred to water for cooling to room temperature, and the time for transfer from the furnace to the water does not exceed 10 seconds; Step (6) graded aging treatment: the cooled ingot or casting in step (5) is placed in a muffle furnace for insulation at a temperature of 230°C. After 30 minutes of insulation, the temperature is lowered to 185°C and the insulation is continued for 3 hours. The ingot or casting is cooled with the furnace to obtain an ingot or casting.

[0033] Example 16 A high manganese content Al-Cu alloy composition for metal mold casting La, Ce alloying and a heat treatment process thereof, comprising the following steps: Step (1) using industrial pure aluminum, Al20Cu, Al20Mn, Al20M, Al10TiV, Al10Zr5B, Al10La and Al10Ce master alloys as raw materials, calculating and weighing raw materials that meet the designed composition; the designed alloy composition is Cu: 4.60wt.%, Mn: 0.40wt.%, Mg: 0.20wt.%, Ti and Zr elements are 0.20wt.%, V and B elements are 0.15wt.%, the total content of other impurities does not exceed 0.15wt.%, and the content of a single impurity component does not exceed 0.02wt.%, and the balance is Al; the amount of alloy element Ce added is 0.10wt.%; Step (2) uses a general smelting technology to sequentially place the raw materials in step (1) into a graphite crucible according to the general smelting technical specifications to prepare an Al-Cu alloy. The conventional process includes heating, melting, adding materials (supplementing the element content decreased due to burning and adding alloying element Ce (added in the form of Al10Ce)), degassing, refining, and heat preservation to obtain an alloy melt; Step (3) heating the metal casting mold with a cylindrical and square inner cavity to 220° C. Step (4) using a common casting technology, pouring the material in step (2) into the casting mold in step (3), followed by natural cooling to obtain an ingot or casting, and then performing a heat treatment; Step (5) solution treatment: placing the ingot or casting in step (4) into a muffle furnace for preheating and heat preservation at a temperature of 480° C. for 12 hours, taking out the ingot or casting and transferring it to water for cooling to room temperature, and the time for transferring from the furnace to the water shall not exceed 10 seconds; Step (6) graded aging treatment: the cooled ingot or casting in step (5) is placed in a muffle furnace for insulation at a temperature of 210° C. After insulation for 30 minutes, the temperature is reduced to 165° C. and the insulation time is continued for 4 hours. The ingot or casting is cooled in the furnace or taken out and then cooled naturally to obtain an ingot or casting.

[0034] It should be noted that the embodiments described in the present invention are only used to express the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A high manganese content Al-Cu alloy composition for metal mold casting La, Ce alloying and its heat treatment process, characterized in that: Through the design of Mn and Mg elements, the effect of Mn element is fully exerted and the alloying effect of La and Ce elements is coordinated to reduce segregation and inhibit the tendency of hot cracking, and improve the uniformity of the structure of the alloy ingot or casting; specifically, the following steps are included: Step (1) using industrial pure aluminum, Al20Cu (Al-20 wt.% Cu) master alloy, Al20Mn (Al-20 wt.% Mn) master alloy, Al20Mg (Al-20 wt.% Mg) master alloy, Al10TiV (Al-10 wt.% Ti-1.0 wt.% V) master alloy and Al10Zr5B (Al-10 wt.% Zr-1.0 wt.% B) master alloy as raw materials, adding alloying elements using Al10La (Al-10 wt.% La) and Al10Ce (Al-10 wt.% Ce) master alloy as raw materials, calculating and weighing each raw material that meets the design composition; The alloy composition range is Cu: 4.60wt.% -6.60wt.%, Mn: 0.40wt.% -0.95wt.%, Mg: 0.20wt.% -0.32wt.%, the total amount of Ti and Zr elements does not exceed 0.40wt.%, the total amount of V and B does not exceed 0.3wt.%, the total content of other impurities does not exceed 0.15wt.%, and the content of a single impurity component does not exceed 0.02wt.%, and the balance is Al; in addition, alloying elements La or Ce elements are added, and the addition amount is 0.10wt.% -0.30wt.% of the weight of the alloy to be prepared; Step (2) using a general smelting technology, placing the raw materials in step (1) in a graphite crucible in sequence according to the general smelting technical specifications to prepare an Al-Cu alloy, the process comprising heating, melting, adding materials to supplement the element content decreased due to burning, adding alloying elements La or Ce, degassing, refining, and heat preservation to obtain an alloy melt; Step (3) heating the metal casting mold with a cylindrical and square inner cavity to 220°C-350°C; Step (4) using a general casting technology to perform metal mold gravity casting and metal mold low-pressure casting, introducing the melt in step (2) into the casting mold of step (3) by selecting a melt injection method according to different casting processes, and then cooling naturally or using a forced cooling method to obtain an ingot or casting, and then performing a solution treatment and a graded aging treatment; Step (5) solution treatment: placing the ingot or casting in step (4) into a muffle furnace for preheating and heat preservation at a temperature range of 480°C to 580°C for a heat preservation time of 12 to 18 hours, taking out the ingot or casting and placing it in an environment where a cooling rate of 3000°C / h to 10000°C / h can be achieved for cooling, i.e., quenching to room temperature, and the time for transferring from the furnace to water does not exceed 10 seconds; Step (6) graded aging treatment: the cooled ingot or casting in step (5) is placed in a muffle furnace or a blast drying oven for insulation at a temperature range of 210°C-230°C for 30 minutes-45 minutes, and then the temperature is lowered (or transferred to another device) to 130°C-160°C for 8-10 hours, or lowered to 165°C-180°C for 4-6 hours, or lowered to 185°C-205°C for 2-5 hours, and then cooled in the furnace or the ingot or casting is taken out and then cooled naturally to obtain a final ingot or casting product.

2. The Al-Cu alloy composition with high manganese content for La and Ce alloying in metal mold casting and its heat treatment process as claimed in claim 1, characterized in that: The alloying element La added in the step (2) is added in the form of Al10La, and the alloying element Ce added is added in the form of Al10Ce.

3. The high manganese content Al-Cu alloy composition for La and Ce alloying in metal mold casting and its heat treatment process as claimed in claim 1, characterized in that: The cooling method in step (4) is water cooling or air cooling.

4. The high manganese content Al-Cu alloy composition for La and Ce alloying in metal mold casting and its heat treatment process as claimed in claim 1, characterized in that: The environment for achieving a cooling rate of 3000°C / h-10000°C / h in step (5) is water or a water-soluble quenching liquid of a high molecular polymer.

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