High-elongation beryllium-aluminum alloy and preparation method therefor

Abstract

The present invention relates to the technical field of the preparation of a casting beryllium-aluminum alloy. Disclosed are a high-elongation beryllium-aluminum alloy and a preparation method therefor. The preparation method comprises: placing a pretreated beryllium raw material and aluminum raw material into a smelting crucible, and then subjecting the beryllium raw material and the aluminum raw material to 3-5 instances of vacuum smelting, so as to obtain a beryllium-aluminum alloy melt; and rapidly pouring the beryllium-aluminum alloy melt into a water-cooling mold to cool same to room temperature, and obtaining a beryllium-aluminum alloy cast ingot after demolding, wherein the pouring rate is 200-500 g / s, and the temperature of cooling water used in the water-cooling mold is less than or equal to 10°C. The elongation of the prepared beryllium-aluminum alloy is up to 15-20%. In the present invention, using the preparation process of fully melting and uniformly mixing two metals, namely, beryllium and aluminum, by means of a method of multiple instances of vacuum melting, and then rapidly pouring the beryllium-aluminum alloy melt into a water-cooling mold for rapid cooling greatly improves the uniformity and compactness of the internal structure of the beryllium-aluminum alloy, thereby improving the elongation of the alloy.

Description

High-elongation beryllium-aluminum alloy and preparation method thereof TECHNICAL FIELD

[0001] The present application belongs to the technical field of preparation of cast beryllium-aluminum alloy, and particularly relates to a high-elongation beryllium-aluminum alloy and a preparation method thereof. BACKGROUND

[0002] Beryllium-aluminum alloy is a light metal combining the excellent properties of beryllium and aluminum. Beryllium-aluminum alloy is superior to traditional structural metals in low density, high specific strength and stiffness, high thermal conductivity and low thermal expansion coefficient, and has a broad application prospect in the industries of aircraft, spacecraft and weapon equipment. Since there is no obvious mutual solid solubility between aluminum and beryllium, they also cannot form intermetallic compounds together. Therefore, beryllium-aluminum alloy is one of the most important multi-component materials composed of discontinuous reinforced beryllium phase and continuous aluminum phase, and is considered as a beryllium reinforced aluminum matrix composite.

[0003] However, the solidification mode of beryllium-aluminum alloy is a typical "volume solidification" mode, and the wide solidification interval determines that defects such as shrinkage cavity and shrinkage porosity inevitably occur in the material, which cannot truly reflect the plasticity of the aluminum matrix composite.

[0004] At present, the research focus of beryllium-aluminum alloy is on the improvement of strength, and the plasticity of beryllium-aluminum alloy has not been greatly improved.

[0005] Therefore, the prior art needs to be improved. SUMMARY

[0006] To solve the above technical problems, the present application provides a high-elongation beryllium-aluminum alloy and a preparation method thereof. The present application adopts a method of multiple vacuum melting to fully melt and uniformly mix the two metals of beryllium and aluminum, and then rapidly pours the beryllium-aluminum alloy melt into a water-cooled mold for rapid cooling, which greatly improves the internal organization density of the beryllium-aluminum alloy and further improves the elongation (plasticity) of the alloy.

[0007] The present application provides a preparation method of a high-elongation beryllium-aluminum alloy. The mass percentage of beryllium in the beryllium-aluminum alloy is 60-65wt%, and the balance is aluminum.

[0008] The preparation method comprises the following steps:

[0009] Step S1, the pretreated beryllium raw material and aluminum raw material are put into a smelting crucible, and then the beryllium raw material and aluminum raw material are subjected to 3-5 times of vacuum melting to obtain a beryllium-aluminum alloy melt;

[0010] Step S2, the beryllium-aluminum alloy melt is rapidly poured into a water-cooled mold for cooling to room temperature, and a beryllium-aluminum alloy ingot is obtained after demolding;

[0011] The pouring rate is 200-500 g / s, and the temperature of the cooling water used for the water-cooled mold is ≤10 ℃.

[0012] In the step S1, after each vacuum melting, the beryllium aluminum alloy melt is naturally cooled to room temperature in the melting crucible to obtain a beryllium aluminum alloy ingot, and the beryllium aluminum alloy ingot is placed in the melting crucible in a reverse direction before the next vacuum melting.

[0013] In the step S1, the vacuum melting includes a holding stage after the beryllium raw material and the aluminum raw material are completely melted, and the holding time is 10-30 min.

[0014] In the step S1, the vacuum degree of the vacuum melting is less than 5.0*10 -3 Pa, and the heating power increasing rate of the vacuum melting is 10-30 kw / min.

[0015] In the step S1, the pretreatment specifically includes:

[0016] The beryllium raw material and the aluminum raw material are mechanically polished, and then the beryllium raw material and the aluminum raw material after the mechanical polishing are placed in an organic solvent for ultrasonic cleaning and then dried.

[0017] The ultrasonic cleaning time is 30-60 min, the drying temperature is 80-100 ℃, and the drying time is 60-90 min.

[0018] In the step S1, the beryllium raw material and the aluminum raw material are both in a sheet or block shape.

[0019] In the step S1, the beryllium raw material and the aluminum raw material are both in a sheet or block shape.

[0020] In the step S1, the beryllium raw material and the aluminum raw material are both in a sheet or block shape.

[0021] In the step S1, the beryllium raw material and the aluminum raw material are both in a sheet or block shape.

[0022] In the step S1, the beryllium raw material and the aluminum raw material are both in a sheet or block shape.

[0023] The second aspect of the present application provides a high-elongation beryllium-aluminum alloy prepared by the method for preparing high-elongation beryllium-aluminum alloy, wherein the tensile strength of the beryllium-aluminum alloy is 110-120 MPa, the yield strength is 50-60 MPa, and the elongation is 15-20%.

[0024] The scheme provided by the present application has the following technical effects:

[0025] The present application adopts the method of multiple vacuum melting to fully melt and uniformly mix the two metals of beryllium and aluminum, and then rapidly pours the beryllium-aluminum alloy melt into a water-cooled mold for rapid cooling, which greatly improves the uniformity and compactness of the internal structure of the beryllium-aluminum alloy, and further improves the elongation of the alloy.

[0026] In addition, the beryllium-aluminum alloy ingot prepared by the method of the present application has uniform internal structure and good compactness, and has no obvious defects such as shrinkage cavity and shrinkage porosity. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings needed to be used in the description of the specific embodiments or the prior art. Obviously, the drawings described below are some embodiments of the present application, and those skilled in the art can obtain other drawings according to these drawings without creative labor.

[0028] Figure 1 is a photograph of the internal structure of the high-elongation beryllium-aluminum alloy obtained in the specific embodiment 1 of the present application.

[0029] Figure 2 is a photograph of the internal structure of the high-elongation beryllium-aluminum alloy obtained in the specific embodiment 2 of the present application.

[0030] Figure 3 is a photograph of the internal structure of the high-elongation beryllium-aluminum alloy obtained in the specific embodiment 3 of the present application.

[0031] Figure 4 is a photograph of the internal structure of the beryllium-aluminum alloy obtained in the comparative example 1.

[0032] Figure 5 is a photograph of the internal structure of the beryllium-aluminum alloy obtained in the comparative example 2. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical scheme and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings. Obviously, the described embodiments are only some of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0034] The embodiment provides a preparation method of a high-elongation beryllium-aluminum alloy, the mass percentage of beryllium in the beryllium-aluminum alloy is 60-65wt%, and the balance is aluminum;

[0035] The preparation method comprises the following steps:

[0036] In step S1, the pretreated beryllium raw material and the aluminum raw material are put into a smelting crucible, and then the beryllium raw material and the aluminum raw material are subjected to 3-5 times of vacuum smelting to obtain a beryllium-aluminum alloy melt.

[0037] In step S2, the beryllium-aluminum alloy melt is rapidly poured into a water-cooled mold to be cooled to room temperature, and a beryllium-aluminum alloy ingot is obtained after demolding.

[0038] The embodiment fully melts and uniformly mixes the two metals of beryllium and aluminum through 3-5 times of vacuum smelting to ensure uniform alloy composition, and then the beryllium-aluminum alloy melt is rapidly poured into a water-cooled mold to be rapidly cooled, which greatly improves the internal organization density of the beryllium-aluminum alloy and further improves the elongation of the alloy. In addition, if the beryllium-aluminum alloy is slowly cooled, there are many defects in the beryllium-aluminum alloy due to the large specific heat capacity of beryllium.

[0039] Meanwhile, the beryllium raw material and the aluminum raw material are pretreated before vacuum smelting to remove surface oxides and surface contamination of the raw materials, so as to ensure the purity of the raw materials and further reduce internal shrinkage holes, shrinkage porosities and other defects of the beryllium-aluminum alloy.

[0040] The pouring rate is 200-500g / s, and the temperature of the cooling water used by the water-cooled mold is ≤10℃.

[0041] In the embodiment, when the pouring rate is lower than 200g / s, the purpose of rapidly pouring the melt and rapidly cooling the melt cannot be achieved, and when the pouring rate is higher than 500g / s, the gas cannot be discharged in time due to the too fast pouring rate, so that there are many pores in the beryllium-aluminum alloy, therefore, the pouring rate is controlled to be 200-500g / s in the embodiment.

[0042] The purpose of the embodiment is to rapidly cool the melt, therefore, the temperature of the cooling water cannot be too high, and the temperature of the cooling water is controlled to be ≤10℃ in the embodiment.

[0043] In some embodiments, in the step S1, after each time of vacuum smelting, the beryllium-aluminum alloy melt is naturally cooled to room temperature in the smelting crucible to obtain a beryllium-aluminum alloy ingot, and the beryllium-aluminum alloy ingot is put into the smelting crucible in the reverse direction for the next time of vacuum smelting.

[0044] In some embodiments, in the step S1, the vacuum melting includes a holding stage after the beryllium raw material and the aluminum raw material are completely melted, and the holding time is 10-30 min, so that the alloy solution is fully stirred and mixed uniformly in the middle of the crucible.

[0045] In some embodiments, in the step S1, the vacuum degree of the vacuum melting is less than 5.0*10 -3 Pa, and the heating power increasing rate of the vacuum melting is 10-30 kw / min, so that the solution is uniformly heated and does not splash.

[0046] Preferably, the temperature rising process of the vacuum melting is observed from the observation port.

[0047] In some embodiments, in the step S1, the pretreatment specifically includes:

[0048] The beryllium raw material and the aluminum raw material are mechanically polished, and then the beryllium raw material and the aluminum raw material after mechanical polishing are ultrasonically cleaned in an organic solvent and then dried.

[0049] The ultrasonic cleaning time is 30-60 min, the drying temperature is 80-100 °C, and the drying time is 60-90 min.

[0050] Preferably, the organic solvent is acetone or ethanol.

[0051] In some embodiments, in the step S1, the aluminum raw material with a low melting point is placed at the bottom of the melting crucible, and the beryllium raw material with a high melting point is placed on the upper layer of the aluminum raw material.

[0052] The beryllium raw material with a high melting point is placed on the upper layer of the aluminum raw material with a low melting point, so that the raw materials are fully melted.

[0053] In some embodiments, the purity of the beryllium raw material and the aluminum raw material is greater than 99%.

[0054] In some embodiments, the beryllium raw material and the aluminum raw material are in a sheet or block shape.

[0055] In some embodiments, the beryllium raw material and the aluminum raw material are placed in a transverse manner, so as to facilitate induction heating.

[0056] In some embodiments, the melting crucible can rotate by ±90°, so as to facilitate rapid pouring of the beryllium-aluminum alloy melt into a water-cooled mold.

[0057] The second aspect of the embodiment provides a high-elongation beryllium-aluminum alloy prepared by the preparation method of the high-elongation beryllium-aluminum alloy.

[0058] Embodiment 1

[0059] In the first step, the beryllium raw material and the aluminum raw material are mechanically polished, and then the beryllium raw material and the aluminum raw material after mechanical polishing are ultrasonically cleaned in acetone and dried.

[0060] The purity of the beryllium raw material and the aluminum raw material is greater than 99%, the beryllium raw material and the aluminum raw material are in a sheet or block shape and are placed horizontally, the beryllium raw material with a high melting point is placed on the upper layer of the aluminum raw material, the mass ratio of the beryllium raw material to the aluminum raw material is 3:2, the ultrasonic cleaning time is 30 min, the drying temperature is 80℃, and the drying time is 60 min.

[0061] In the second step, the pretreated beryllium raw material and the aluminum raw material are placed in a smelting crucible, and the vacuum degree is reduced to 5.0×10 -3 Pa, vacuum smelting is started, the heating power increase rate of vacuum smelting is set to 20 kw / min, until the beryllium raw material and the aluminum raw material are completely melted, the heating is stopped after 10-30 min of heat preservation, the beryllium-aluminum alloy melt is naturally cooled to room temperature in the smelting crucible to obtain a beryllium-aluminum alloy ingot, the beryllium-aluminum alloy ingot is placed in the smelting crucible in the opposite direction, and the next vacuum smelting is carried out. A total of 3 times of vacuum smelting are performed to obtain a beryllium-aluminum alloy melt to be poured.

[0062] In the third step, the beryllium-aluminum alloy melt to be poured is quickly poured into a water-cooled mold for cooling to room temperature, and a beryllium-aluminum alloy ingot is obtained after demolding.

[0063] The pouring rate is 200 g / s, and the temperature of the cooling water used by the water-cooled mold is 5±3℃.

[0064] The beryllium-aluminum alloy ingot obtained in Embodiment 1 is subjected to chemical composition and mechanical property detection. The mass percentage of beryllium in the beryllium-aluminum alloy ingot is 59.9%, the mass percentage of aluminum is 40.1%, the tensile strength is 112.5 MPa, the yield strength is 52.6 MPa, and the elongation is 15.2%.

[0065] As shown in FIG. 1, the internal structure of the beryllium-aluminum alloy ingot prepared in Embodiment 1 is uniform, the compactness is good, and there are no obvious defects such as shrinkage holes and shrinkage porosities.

[0066] Embodiment 2

[0067] The difference from Example 1 is that the mass ratio of beryllium raw material and aluminum raw material is 62:38, the ultrasonic cleaning time is 45 min, the drying temperature is 90℃, the drying time is 80 min; the heating power increasing rate of vacuum melting is 10 kw / min, and the total number of vacuum melting is 4; the pouring rate is 300 g / s, and the temperature of cooling water used in water-cooled mold is 6±3℃.

[0068] The beryllium aluminum alloy ingot obtained in Example 2 is detected for chemical composition and mechanical properties. The detection shows that the mass percentage of beryllium in the beryllium aluminum alloy ingot is 61.9%, the mass percentage of aluminum is 38.1%, the tensile strength is 115.3 MPa, the yield strength is 56.2 MPa, and the elongation is 18.1%.

[0069] As shown in Figure 2, the internal structure of the beryllium aluminum alloy ingot prepared in Example 2 is uniform, and has good compactness without obvious defects such as shrinkage holes and shrinkage porosity.

[0070] Example 3

[0071] The difference from Example 1 is that the mass ratio of beryllium raw material and aluminum raw material is 65:35, the ultrasonic cleaning time is 60 min, the drying temperature is 100℃, the drying time is 90 min; the heating power increasing rate of vacuum melting is 30 kw / min, and the total number of vacuum melting is 5; the pouring rate is 400 g / s, and the temperature of cooling water used in water-cooled mold is 4±3℃.

[0072] The beryllium aluminum alloy ingot obtained in Example 3 is detected for chemical composition and mechanical properties. The detection shows that the mass percentage of beryllium in the beryllium aluminum alloy ingot is 64.8%, the mass percentage of aluminum is 35.2%, the tensile strength is 119.8 MPa, the yield strength is 59.7 MPa, and the elongation is 20.0%.

[0073] As shown in Figure 3, the internal structure of the beryllium aluminum alloy ingot prepared in Example 3 is uniform, and has good compactness without obvious defects such as shrinkage holes and shrinkage porosity.

[0074] Comparative Example 1

[0075] The difference from Example 1 is that the total number of vacuum melting is 2; the pouring rate is 150 g / s, and the temperature of cooling water used in water-cooled mold is 25±3℃.

[0076] The beryllium aluminum alloy ingot obtained in Comparative Example 1 is detected for chemical composition and mechanical properties. The detection shows that the mass percentage of beryllium in the beryllium aluminum alloy ingot is 60.1%, the mass percentage of aluminum is 39.9%, the tensile strength is 92.1 MPa, the yield strength is 41.6 MPa, and the elongation is 1.9%.

[0077] As shown in Figure 4, the internal structure of the beryllium aluminum alloy ingot prepared by the comparative example 1 has obvious defects such as shrinkage cavity and shrinkage porosity.

[0078] Comparative example 2

[0079] The difference from the example 1 is that the vacuum melting is performed for 2 times in total; the pouring rate is 600 g / s, and the temperature of the cooling water used in the water-cooled mold is 25±3℃.

[0080] The beryllium aluminum alloy ingot obtained by the comparative example 2 is detected in terms of chemical composition and mechanical properties.

[0081] As shown in Figure 5, the internal structure of the beryllium aluminum alloy ingot prepared by the comparative example 2 has obvious defects such as shrinkage cavity and shrinkage porosity.

[0082] In summary, the scheme provided by the present application has the following technical effects:

[0083] The present application greatly improves the uniformity and compactness of the internal structure of the beryllium aluminum alloy, and further improves the elongation of the alloy, by using the method of multiple vacuum melting to fully melt and uniformly mix the two metals of beryllium and aluminum, and then rapidly pouring the beryllium aluminum alloy melt into a water-cooled mold for rapid cooling.

[0084] In addition, the beryllium aluminum alloy ingot prepared by the method of the present application has uniform internal structure and good compactness, and has no obvious defects such as shrinkage cavity and shrinkage porosity.

[0085] Please note that any combination of the technical features of the above examples can be made, and in order to make the description simple, all possible combinations of the technical features in the above examples are not described, however, as long as the combination of the technical features does not exist contradictory, it should be considered as the scope of the present application. The above examples only express several embodiments of the present application, and the description is more specific and detailed, but it should not be understood as limiting the scope of the patent. It should be noted that for ordinary skilled in the art, without departing from the concept of the present application, a number of variations and improvements can be made, which are within the scope of the present application. Therefore, the scope of the patent of the present application should be subject to the appended claims.

Claims

1. A method of producing a high-elongation beryllium-aluminum alloy, characterized by, The beryllium aluminum alloy contains 60-65wt% of beryllium and the balance of aluminum; The preparation method comprises the following steps: S1, putting the pretreated beryllium raw material and aluminum raw material into a smelting crucible, and then vacuum smelting the beryllium raw material and aluminum raw material for 3-5 times to obtain a beryllium aluminum alloy melt; S2, rapidly pouring the beryllium aluminum alloy melt into a water-cooled mold for cooling to room temperature, and then demolding to obtain a beryllium aluminum alloy ingot; The pouring rate is 200-500g / s, and the temperature of the cooling water used by the water-cooled mold is ≤10℃.

2. The method of producing a high-elongation beryllium-aluminum alloy according to claim 1, characterized by, In the step S1, after each vacuum smelting, the beryllium aluminum alloy melt is naturally cooled to room temperature in the smelting crucible to obtain a beryllium aluminum alloy ingot, and the beryllium aluminum alloy ingot is placed in the smelting crucible in the opposite direction for the next vacuum smelting.

3. The method of producing a high-elongation beryllium-aluminum alloy according to claim 1, characterized by, In the step S1, the vacuum smelting comprises a holding stage after the beryllium raw material and aluminum raw material are completely melted, and the holding time is 10-30min.

4. The method of producing a high-elongation beryllium-aluminum alloy according to claim 1, characterized by, In the step S1, the vacuum degree of the vacuum melting is less than 5.0x10 -3 Pa, and the heating power increasing rate of the vacuum melting is 10-30 kw / min.

5. The method of producing a high-elongation beryllium-aluminum alloy according to claim 1, characterized by, In the step S1, the pretreatment specifically comprises: Mechanically polishing the beryllium raw material and aluminum raw material, ultrasonic cleaning the beryllium raw material and aluminum raw material after mechanical polishing, and then drying; The ultrasonic cleaning time is 30-60min, the drying temperature is 80-100℃, and the drying time is 60-90min.

6. The method of producing a high-elongation beryllium-aluminum alloy according to claim 1, characterized by, In the step S1, the low-melting-point aluminum raw material is placed at the bottom of the smelting crucible, and the high-melting-point beryllium raw material is placed on the upper layer of the aluminum raw material.

7. The method of producing a high-elongation beryllium-aluminum alloy according to claim 1, characterized by, The beryllium raw material and aluminum raw material are both in the form of sheet or block.

8. The method of producing a high-elongation beryllium-aluminum alloy according to claim 7, characterized by, The beryllium raw material and aluminum raw material are placed horizontally.

9. The method of producing a high-elongation beryllium-aluminum alloy according to claim 1, characterized by, The smelting crucible can rotate ±90°.

10. A high-elongation beryllium-aluminum alloy prepared by the method of any one of claims 1-9, wherein the high-elongation beryllium-aluminum alloy has a tensile strength of at least 200 MPa, a yield strength of at least 150 MPa, and an elongation of at least 1.5%. The beryllium aluminum alloy has a tensile strength of 110-120MPa, a yield strength of 50-60MPa, and an elongation of 15-20%.

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