A high-castability beryllium-aluminum alloy and a method for preparing the same
By adding elements such as Ag, Co, Si, and La to beryllium aluminum alloy and refining and stirring, the casting defects and mechanical property problems in the beryllium aluminum alloy casting process were solved, and the preparation of beryllium aluminum alloy with high casting performance, featuring uniform structure, good fluidity and high strength, was achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- NORTHWEST RARE METALS MATERIALS RESEARCH INSTITUTE NINGXIA CO LTD
- Filing Date
- 2023-10-26
- Publication Date
- 2026-06-02
AI Technical Summary
Existing beryllium aluminum alloys are prone to casting defects such as shrinkage porosity, shrinkage cavities, and shrinkage cracks during the casting process, and their mechanical properties are anisotropic, which affects their engineering applications.
A high-casting-performance beryllium aluminum alloy preparation method is adopted. By adding alloying elements such as Ag, Co, Si, and La, and stirring and step-by-step cooling during the refining process, the alloying elements are ensured to be uniformly distributed, reducing microsegregation, and directly cast into a ceramic mold to form a casting.
It improves the fluidity and oxidation resistance of beryllium aluminum alloys, refines grains, reduces casting defects, enhances the uniformity and mechanical properties of the alloy, reduces production costs, and improves production efficiency.
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Figure CN117568597B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of alloy materials technology, and particularly relates to a high-casting-performance beryllium aluminum alloy and its preparation method. Background Technology
[0002] Beryllium-aluminum alloy, as an aluminum-based metal composite material, combines the high elastic modulus and low density of beryllium with the easy machinability and high toughness of aluminum. It possesses characteristics such as light weight, high specific strength, high specific stiffness, good thermal stability, high toughness, high modulus, and good corrosion resistance, making it an important new structural material widely used in aerospace and other civilian fields. Currently, the main manufacturing processes for beryllium-aluminum alloy are investment casting, powder metallurgy, and pressure processing. Comparatively, investment casting for beryllium-aluminum alloy structural components offers advantages such as simple process, low cost, and high material utilization, making it one of the main methods for the industrial application of beryllium-aluminum alloy worldwide.
[0003] Due to the low solid solubility and large melting point difference between pure beryllium and aluminum, the solidification process of the alloy using conventional casting methods involves a wide metastable miscibility gap and solidification range. This leads to complete phase separation of beryllium and aluminum during solidification. Beryllium-aluminum alloys are essentially composite materials of two independently existing pure beryllium and pure aluminum, forming an interpenetrating three-dimensional network structure. The beryllium phase often manifests as well-developed columnar dendrites, while the aluminum phase fills the voids between the dendrite arms of the beryllium grains. The difference in solidification shrinkage rates and asynchronous solidification of the two metals result in poor metal fluidity during casting, making the alloy prone to casting defects such as shrinkage porosity, shrinkage cavities, and shrinkage cracks. Furthermore, the coarse beryllium dendritic structure often leads to anisotropy in the alloy's mechanical properties; when the melt cooling rate is slow, the density difference between the two metals will cause macroscopic segregation in the alloy. Adding alloying elements as modifiers can effectively improve the microstructure and mechanical properties of cast beryllium aluminum alloys. However, if the melt cooling rate is insufficient, micro-segregation of alloying elements within the beryllium dendrite interstices is highly likely to occur. These casting defects in various beryllium aluminum alloys significantly reduce macroscopic mechanical properties such as the alloy's elastic modulus, tensile strength, and elongation, greatly limiting the engineering applications of cast beryllium aluminum alloys. Summary of the Invention
[0004] One of the objectives of this invention is to provide a method for preparing a beryllium-aluminum alloy with high casting performance. The beryllium-aluminum alloy prepared by this method has a uniform and dense microstructure, good fluidity, high casting performance, is easy to cast and form, and has fewer casting defects.
[0005] The second objective of this invention is to provide a beryllium-aluminum alloy with high casting performance.
[0006] To achieve one of the above objectives, the present invention employs the following technical solution:
[0007] A method for preparing a beryllium aluminum alloy with high casting performance, the method comprising the following steps:
[0008] Step S1: Prepare Be ingots, Al ingots, Ag ingots, Co sheets, Si and La metals according to the following components and their weight percentages;
[0009] Be, 40–70%; Al, 20–50%; Ag, 1–4.0%; Co, 0.5–2%; Si, 0.5–2%; La, 0.1–1%, the remainder being unavoidable impurities;
[0010] The purity of the Be ingot is above 99%, the purity of the Al and Ag ingots is above 99.5%, and the purity of the Co, Si, and La metals is above 99.9%.
[0011] Step S2: After placing Ag ingots, Co sheets and La metal at the bottom of the crucible, add Al ingots and beryllium ingots in sequence for refining to obtain a melt;
[0012] Step S3: After stirring the melt evenly, cool it down in stages to the casting temperature, then pour it into the pre-made ceramic mold shell, let it stand in the furnace for 3-5 minutes, and then cool it outside the furnace.
[0013] Furthermore, in step S2, the refining process includes:
[0014] First, a mechanical pump is used to evacuate the vacuum to 4.2 × 10⁻⁶. 2 ~5×10 2 Pa, then a Roots pump was used to evacuate the vacuum by 2 Pa to 8 Pa, and the temperature was raised in stages to 1360 to 1390℃, and held for 20 to 30 minutes.
[0015] Furthermore, the refining temperature is 1370–1380°C, and the temperature is maintained for 23–27 minutes.
[0016] Furthermore, the segmentation includes a first stage and a second stage, with heating rates of 15-20 kW / h and 30-60 kW / h for the first stage and the second stage, respectively. The heating rate is first increased at 15-20 kW / h until the material is completely melted; then, the heating rate is increased at 30-60 kW / h to the refining temperature, ensuring that the ceramic crucible heats up steadily and does not crack.
[0017] Furthermore, the heating rate in the first stage is 16–18 kW / h;
[0018] The heating rate in the second stage is 40–50 kW / h.
[0019] Furthermore, when the temperature reaches the refining temperature, the Roots pump is turned off to prevent material splashing.
[0020] Furthermore, in step S3, the specific process of the stepped cooling includes:
[0021] First, cool down at a rate of 20-25 KW / h for 10-30 minutes; then cool down to 1150-1170℃ at a rate of 30-40 KW / h before casting.
[0022] Furthermore, the external cooling process involves using an axial flow fan to blow air, and adding dry ice or ice blocks to the air outlet of the axial flow fan.
[0023] Furthermore, the crucible is an alumina ceramic crucible.
[0024] The temperature measurement in this invention uses a handheld or fixed-position dual-color infrared thermometer to ensure the accuracy of the temperature measurement. The cooling adopts a stepped cooling method to reduce the temperature to 10KW.
[0025] To ensure the uniformity of the molten metal temperature, the crucible is continuously rotated during the cooling process of this invention.
[0026] To achieve the second objective mentioned above, the present invention employs the following technical solution:
[0027] A high-castability beryllium aluminum alloy, comprising the following components and their weight percentages:
[0028] Be, 40-70%; Al, 20-50%; Ag, 1-4.0%; Co, 0.5-2%; Si, 0.5-2%; La, 0.1-1%, the remainder being unavoidable impurities.
[0029] In summary, the technical solution of the present invention has the following technical effects:
[0030] This invention improves the fluidity, filling ability, and oxidation resistance of beryllium-aluminum alloy melt by adding alloying elements silver, cobalt, silicon, and lanthanum. The addition of lanthanum refines the grain size of the beryllium-aluminum alloy, increasing its strength. The stirring of the melt ensures uniform distribution of alloying elements, reducing interdendritic microsegregation and resulting in consistent alloy properties. The process is investment casting, where molten metal is directly poured into a ceramic mold to form a casting, producing castings with good internal quality and precise dimensions. This invention optimizes the alloy composition and production process, offering advantages such as a short process flow, low cost, and no steel mold required. The process is simple, with high production efficiency and low production costs. The alloy structure is uniform and dense, with good fluidity and casting performance, making it easy to cast. The produced beryllium-aluminum alloy has fewer casting defects, better internal quality, and significantly improved mechanical properties. Attached Figure Description
[0031] Figure 1 The image shows the internal metallographic structure of the beryllium aluminum alloy in Example 1.
[0032] Figure 2 Photographs of the internal metallographic structure of the beryllium aluminum alloy in Example 2;
[0033] Figure 3 Photographs of the internal metallographic structure of the beryllium aluminum alloy in Example 3;
[0034] Figure 4 Photograph of the internal metallographic structure of the beryllium aluminum alloy in Example 4;
[0035] Figure 5 This is a photograph of the internal metallographic structure of the beryllium aluminum alloy in Example 5. Detailed Implementation
[0036] Example 1:
[0037] (1) Check whether the circulating water, electricity, and compressed air of the medium frequency induction furnace are normal, and whether the crucible is normal;
[0038] (2) Prepare the ingredients according to the following weight proportions: Be, 60%; Al, 34.5%; Ag, 3.0%; Co, 1.0%; Si, 1.0%; La, 0.5%.
[0039] (3) Clean the furnace chamber and load the prepared materials into the furnace in sequence;
[0040] (4) Turn on the mechanical pump to evacuate to a vacuum level of 4.6 × 10⁻� 2 Pa, start the Roots pump and evacuate to 5Pa; start the medium frequency power supply and start heating, first heating at a rate of 18KW / h until the material is completely melted, then heating at a rate of 40KW / h to 1380℃, hold for 27 minutes for refining, and thoroughly stir evenly with electromagnetic stirring; then cooling at a rate of 20KW / h for 20 minutes; then cooling at a rate of 35KW / h to 1150℃ for casting into the mold shell; let stand in the furnace for 4 minutes, then cool outside the furnace.
[0041] The beryllium aluminum alloy casting prepared in this embodiment has a uniform and dense microstructure, good fluidity, is easy to cast, has few casting defects, and its internal metallographic structure is shown in the figure. Figure 1 The beryllium aluminum alloy casting has a tensile strength Rm of 220 MPa and a yield strength Rp. 0.2 The strength is 190 MPa, and the elongation is A. 25 It is 2%.
[0042] Example 2:
[0043] (1) Check whether the circulating water, electricity, and compressed air of the medium frequency induction furnace are normal, and whether the crucible is normal;
[0044] (2) Prepare the ingredients according to the following weight proportions: Be, 70%; Al, 50%; Ag, 1%; Co, 0.5%; Si, 2%; La, 1%.
[0045] (3) Clean the furnace chamber and load the prepared materials into the furnace in sequence;
[0046] (4) Turn on the mechanical pump to evacuate to 5×10 2 Pa, start the Roots pump to evacuate to 8Pa; start the medium frequency power supply to heat, first at a rate of 20KW / h until the material is completely melted, then at a rate of 60KW / h to heat to 1390℃, hold for 30 minutes for refining, and thoroughly electromagnetically stir evenly; then first at a rate of 25KW / h for 30 minutes; then at a rate of 30KW / h to heat to 1155℃, and pour into the mold shell; let stand in the furnace for 5 minutes, then cool outside the furnace.
[0047] The beryllium-aluminum alloy prepared in this embodiment has a uniform and dense microstructure, good fluidity, high casting performance, is easy to cast, has few casting defects, and its internal metallographic structure is shown in the figure. Figure 2 The beryllium aluminum alloy casting has a tensile strength Rm of 240 MPa and a yield strength Rp. 0.2 The strength is 195 MPa, and the elongation is A. 25 It is 3%.
[0048] Example 3:
[0049] (1) Check whether the circulating water, electricity, and compressed air of the medium frequency induction furnace are normal, and whether the crucible is normal;
[0050] (2) Prepare the ingredients according to the following weight proportions: Be, 40%; Al, 20%; Ag, 4.0%; Co, 2%; Si, 2%; La, 0.1%;
[0051] (3) Clean the furnace chamber and load the prepared materials into the furnace in sequence;
[0052] (4) Turn on the mechanical pump to evacuate to a vacuum level of 4.2 × 10⁻� 2 Pa, start the Roots pump and evacuate to 2Pa; start the medium frequency power supply and start heating, first heating at a rate of 15KW / h until the material is completely melted, then heating at a rate of 30KW / h to 1370℃, hold for 25 minutes for refining, and thoroughly stir evenly with electromagnetic stirring; then cooling at a rate of 22KW / h for 20 minutes; then cooling at a rate of 40KW / h to 1170℃ for casting into the mold shell; let stand in the furnace for 4 minutes, then cool outside the furnace.
[0053] The beryllium-aluminum alloy prepared in this embodiment has a uniform and dense microstructure, good fluidity, high casting performance, is easy to cast, has few casting defects, and its internal metallographic structure is shown in the figure. Figure 3 The beryllium aluminum alloy casting has a tensile strength Rm of 230 MPa and a yield strength Rp. 0.2 The strength is 195 MPa, and the elongation is A. 25 It is 2.5%.
[0054] Example 4:
[0055] (1) Check whether the circulating water, electricity, and compressed air of the medium frequency induction furnace are normal, and whether the crucible is normal;
[0056] (2) Prepare the ingredients according to the following weight proportions: Be, 40%; Al, 20%; Ag, 4.0%; Co, 2%; Si, 2%; La, 0.1%;
[0057] (3) Clean the furnace chamber and load the prepared materials into the furnace in sequence;
[0058] (4) Turn on the mechanical pump to evacuate to a vacuum level of 4.3 × 10⁻� 2 Pa, start the Roots pump and evacuate to 3Pa; start the medium frequency power supply and start heating, first heating at a rate of 17KW / h until the material is completely melted, then heating at a rate of 45KW / h to 1380℃, hold for 28 minutes for refining, and thoroughly stir evenly with electromagnetic stirring; then cooling at a rate of 23KW / h for 15 minutes; then cooling at a rate of 38KW / h to 1165℃ for casting into the mold shell; let stand in the furnace for 3 minutes, then cool outside the furnace.
[0059] The beryllium-aluminum alloy prepared in this embodiment has a uniform and dense microstructure, good fluidity, high casting performance, is easy to cast, has few casting defects, and its internal metallographic structure is shown in the figure. Figure 4 The beryllium aluminum alloy casting has a tensile strength Rm of 240 MPa and a yield strength Rp. 0.2 The strength is 200 MPa, and the elongation is A. 25 It is 3%.
[0060] Example 5:
[0061] (1) Check whether the circulating water, electricity, and compressed air of the medium frequency induction furnace are normal, and whether the crucible is normal;
[0062] (2) Prepare the ingredients according to the following weight ratios: Be, 40%; Al, 20%; Ag, 4.0%; Co, 2%; Si, 2%; La, 0.1%.
[0063] (3) Clean the furnace chamber and load the prepared materials into the furnace in sequence;
[0064] (4) Turn on the mechanical pump to evacuate to a vacuum level of 4.8 × 10⁻� 2Pa, start the Roots pump and evacuate to 6Pa; start the medium frequency power supply and start heating, first heating at a rate of 16KW / h until the material is completely melted, then heating at a rate of 35KW / h to 1370℃, hold for 26 minutes for refining, and thoroughly stir evenly with electromagnetic stirring; then cooling at a rate of 20KW / h for 28 minutes; then cooling at a rate of 30KW / h to 1160℃ for casting into the mold shell; let stand in the furnace for 4 minutes, then cool outside the furnace.
[0065] The beryllium-aluminum alloy prepared in this embodiment has a uniform and dense microstructure, good fluidity, high casting performance, is easy to cast, has few casting defects, and its internal metallographic structure is shown in the figure. Figure 5 The beryllium aluminum alloy casting has a tensile strength Rm of 235 MPa and a yield strength Rp. 0.2 The strength is 200 MPa, and the elongation is A. 25 It is 4%.
[0066] Please note that the technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments have been described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification. The above embodiments only illustrate several implementation methods of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.
Claims
1. A method of producing a high castability beryllium aluminum alloy, characterized by, The preparation method includes the following steps: Step S1: Prepare Be ingots, Al ingots, Ag ingots, Co sheets, Si and La metals according to the following components and their weight percentages; Be, 40–70%; Al, 20–50%; Ag, 1–4.0%; Co, 0.5–2%; Si, 0.5–2%; La, 0.1–1%, the remainder being unavoidable impurities; The purity of the Be ingot is 99%, the purity of the Al and Ag ingots is 99.5%, and the purity of the Co sheet, Si and La metal is 99.9%. Step S2: After placing Ag ingots, Co sheets, Si and La metals at the bottom of the crucible, Al ingots and beryllium ingots are added in sequence for refining to obtain a melt; In step S2, the refining process includes: First, the mechanical pump is used to vacuumize to 4.2*10 2 2 Pa, then the Roots pump is used to vacuumize to 2 Pa~8 Pa, and the temperature is raised to 1360~1390℃ in sections, and the temperature is kept for 20~30 minutes. The segmentation includes a first stage and a second stage, with heating rates of 15~20KW / h and 30~60KW / h for the first stage and the second stage, respectively. Step S3: After stirring the melt evenly, cool it down stepwise to the casting temperature, then pour it into the pre-made ceramic mold shell, let it stand in the furnace for 3-5 minutes, and then cool it outside the furnace. In step S3, the specific process of the stepped cooling includes: First, cool down at a rate of 20~25KW / h for 10~30 minutes; then cool down to 1150~1170℃ at a rate of 30~40KW / h before casting.
2. The production method according to claim 1, characterized by, The refining temperature is 1370~1380℃, and the temperature is maintained for 23~27 minutes.
3. The preparation method according to claim 2, characterized in that, The heating rate in the first stage is 16~18 KW / h; The heating rate in the second stage is 40~50KW / h.
4. The preparation method according to claim 3, characterized in that, When the temperature reaches the refining temperature, turn off the Roots pump.
5. The preparation method according to claim 4, characterized in that, The external cooling process is as follows: an axial flow fan is used to blow air, and dry ice or ice blocks are added to the air outlet of the axial flow fan.
6. The preparation method according to claim 5, characterized in that, The crucible is an alumina ceramic crucible.
7. A beryllium aluminum alloy with high casting performance, characterized in that, The high-casting-performance beryllium aluminum alloy is prepared using the preparation method described in any one of claims 1 to 6.