High-density beryllium-aluminum alloy and preparation method thereof

Abstract

The invention discloses a high-density beryllium-aluminum alloy and a preparation method thereof, and relates to the technical field of beryllium-aluminum alloys, the method sequentially comprises the following steps: (1) mixing beryllium powder, aluminum powder and a surfactant, then carrying out mechanical alloying, and then carrying out cold press forming; and (2) the formed alloying material is subjected to stepped hot pressing sintering, and the high-compactness beryllium aluminum alloy is obtained. According to the method, the beryllium-aluminum alloy with the evenly-distributed components is prepared through powder metallurgy, the beryllium-aluminum alloy is further densified in a stepped pressurization mode, the high density of the material is guaranteed, and the beryllium-aluminum alloy with the complex shape, the evenly-distributed components and the high density and the composite material of the beryllium-aluminum alloy can be effectively prepared through the method.

Description

Technical Field

[0001] The present invention relates to the technical field of beryllium-aluminum alloys, and particularly relates to a high-density beryllium-aluminum alloy and a preparation method thereof. Background Art

[0002] Beryllium-aluminum alloys have characteristics such as high specific strength and low thermal expansion coefficient, and are widely used in precision fields such as aerospace inertial devices and optical support structures. Due to the large melting point difference between beryllium and aluminum elements, when preparing beryllium-aluminum alloys by traditional melting and casting methods, composition segregation is likely to occur. The powder metallurgy method can effectively ensure the uniform distribution of the components of beryllium-aluminum alloys, but for beryllium-aluminum alloys prepared at conventional sintering temperatures, the beryllium-aluminum interface bonding is weak, and the material density is limited (not greater than 95%); hot isostatic pressing can effectively solve the problems of composition segregation and low density, but the cost of hot isostatic pressing equipment is high, and it is difficult to prepare materials with complex shapes. Summary of the Invention

[0003] In order to solve the above technical problems, the purpose of the present invention is to provide a high-density beryllium-aluminum alloy and a preparation method thereof.

[0004] The technical solution of the present invention for solving the above technical problems is as follows: A preparation method of a high-density beryllium-aluminum alloy is provided, which successively includes the following steps:

[0005] (1) Mix beryllium powder, aluminum powder and an interfacial active agent, then carry out mechanical alloying, and then cold press into a shape;

[0006] (2) Carry out stepwise hot pressing and sintering on the formed alloyed material to obtain a high-density beryllium-aluminum alloy.

[0007] Further, in step (1), the interfacial active agent is at least one of nano-yttrium oxide, nano-aluminum nitride and nano-silicon carbide.

[0008] Further, the mass ratio of beryllium powder, aluminum powder and the interfacial active agent is 30-65 parts: 35-70 parts: 0.25-1.5 parts.

[0009] Further, in step (1), high-energy ball milling is used for mechanical alloying.

[0010] Further, the ball-to-material ratio of the high-energy ball milling method is 5:1, and the rotation speed is 250-350 rpm.

[0011] Further, in step (1), mechanical alloying is carried out in an argon protection atmosphere.

[0012] Further, in step (1), the pressure range of cold pressing into a shape is 270-350 MPa, and the pressure holding time is 10-20 min.

[0013] Further, in step (2), for the stepped hot-pressing sintering, the pressure in the first stage is 5 - 10 MPa, and the pressure in the second stage is 15 - 25 MPa.

[0014] Further, in step (2), the heating rate is 10 - 20 °C / min, the heat preservation temperature is 580 - 620 °C, and the heat preservation time is 30 - 60 min.

[0015] The present invention also provides a highly dense beryllium-aluminum alloy prepared by the preparation method of the above-mentioned highly dense beryllium-aluminum alloy.

[0016] The present invention has the following beneficial effects:

[0017] The method of the present invention prepares a beryllium-aluminum alloy with a uniformly distributed composition by powder metallurgy, and further densifies the beryllium-aluminum alloy by means of stepped pressing, ensuring the high density of the material. This method can effectively prepare beryllium-aluminum alloys and their composites with complex shapes, uniform composition distributions, and high densities. Specific embodiments

[0018] The principles and features of the present invention are described below. The examples given are only used to explain the present invention and are not intended to limit the scope of the present invention. For those not specified in the examples, the conventional conditions or the conditions recommended by the manufacturer are followed. For the reagents or instruments not specified for the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0019] Example 1

[0020] A highly dense beryllium-aluminum alloy, and its preparation method successively includes the following steps:

[0021] (1) Mix 30 parts of beryllium powder, 69.5 parts of aluminum powder, and 0.5 part of nano silicon carbide, then perform mechanical alloying for 2.5 h by high-energy ball milling, with a ball-to-material ratio of 5:1 and a rotation speed of 350 rpm, and then cold press and form in a stainless-steel mold, with a pressing pressure of 300 MPa and a pressure holding time of 12 min;

[0022] (2) Perform stepped hot-pressing sintering on the formed alloyed material, with 8 MPa in the first stage and 15 MPa in the second stage, a heating rate of 12 °C / min, a heat preservation temperature of 590 °C, and a heat preservation time of 40 min, to obtain a highly dense beryllium-aluminum alloy.

[0023] In this example, a beryllium-aluminum alloy with high density and high thermal conductivity was obtained. The density of the alloy was as high as 97.9%, and the thermal conductivity was 218 W / (m·K).

[0024] Example 2

[0025] A highly dense beryllium-aluminum alloy, and its preparation method successively includes the following steps:

[0026] (1) Mix 60 parts of beryllium powder, 39.5 parts of aluminum powder and 0.5 part of nano yttrium oxide, then carry out mechanical alloying by high-energy ball milling for 3 h, with a ball-to-material ratio of 5:1 and a rotation speed of 320 rpm, and then cold press and form in a stainless steel mold, with a pressing pressure of 270 MPa and a pressure holding time of 15 min;

[0027] (2) Carry out stepwise hot pressing and sintering on the formed alloyed material, with 8 MPa in the first stage, 20 MPa in the second stage, a heating rate of 12 °C / min, a holding temperature of 595 °C, and a holding time of 47 min to obtain a high-density beryllium-aluminum alloy.

[0028] In this example, a beryllium-aluminum alloy with high density and high flexural strength was obtained. The density of the alloy was as high as 98.7%, the flexural strength was 385 MPa, and the thermal expansion coefficient was 11.2×10 -6 / K (25 - 200 °C).

[0029] Example 3

[0030] A high-density beryllium-aluminum alloy, and its preparation method successively includes the following steps:

[0031] (1) Mix 40 parts of beryllium powder, 35 parts of aluminum powder and 0.25 part of nano yttrium oxide, then carry out mechanical alloying by high-energy ball milling, with a ball-to-material ratio of 5:1 and a rotation speed of 250 rpm, and then cold press and form in a stainless steel mold, with a pressing pressure of 270 MPa and a pressure holding time of 10 min;

[0032] (2) Carry out stepwise hot pressing and sintering on the formed alloyed material, with 5 MPa in the first stage, 15 MPa in the second stage, a heating rate of 10 °C / min, a holding temperature of 580 °C, and a holding time of 30 min to obtain a high-density beryllium-aluminum alloy.

[0033] Example 4

[0034] A high-density beryllium-aluminum alloy, and its preparation method successively includes the following steps:

[0035] (1) Mix 65 parts of beryllium powder, 70 parts of aluminum powder and 1.5 parts of nano aluminum nitride, then carry out mechanical alloying by high-energy ball milling, with a ball-to-material ratio of 5:1 and a rotation speed of 350 rpm, and then cold press and form in a stainless steel mold, with a pressing pressure of 350 MPa and a pressure holding time of 20 min;

[0036] (2) Carry out stepwise hot pressing and sintering on the formed alloyed material, with 10 MPa in the first stage, 25 MPa in the second stage, a heating rate of 20 °C / min, a holding temperature of 620 °C, and a holding time of 60 min to obtain a high-density beryllium-aluminum alloy.

[0037] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A preparation method of a high-density beryllium-aluminum alloy, characterized in that, It successively includes the following steps: (1) Mix beryllium powder, aluminum powder and a surfactant, then carry out mechanical alloying, and then cold press into a form; (2) Carry out stepwise hot press sintering on the formed alloyed material to obtain a high-density beryllium-aluminum alloy.

2. The preparation method of the high-density beryllium-aluminum alloy according to claim 1, wherein, In step (1), the surfactant is at least one of nano-yttrium oxide, nano-aluminum nitride and nano-silicon carbide.

3. The preparation method of the high-density beryllium-aluminum alloy according to claim 1, characterized in that, The mass fraction ratio of the beryllium powder, aluminum powder and surfactant is 30-65 parts: 35-70 parts: 0.25-1.5 parts.

4. The preparation method of the high-density beryllium-aluminum alloy according to claim 1, characterized in that, In step (1), mechanical alloying is carried out by the high-energy ball milling method.

5. The preparation method of the high-density beryllium-aluminum alloy according to claim 4, characterized in that, The ball-to-material ratio of the high-energy ball milling method is 5:1, and the rotation speed is 250-350 rpm.

6. The preparation method of the high-density beryllium-aluminum alloy according to claim 1, characterized in that In step (1), mechanical alloying is carried out in an argon protection atmosphere.

7. The preparation method of the high-density beryllium-aluminum alloy according to claim 1, characterized in that, In step (1), the pressure range of the cold pressing is 270-350 MPa, and the pressure holding time is 10-20 min.

8. The preparation method of the high-density beryllium-aluminum alloy according to claim 1, wherein In step (2), for the stepwise hot press sintering, the first stage is 5-10 MPa, and the second stage is 15-25 MPa.

9. The preparation method of the high-density beryllium-aluminum alloy according to claim 1, characterized in that In step (2), the heating rate is 10-20 °C / min, the heat preservation temperature is 580-620 °C, and the heat preservation time is 30-60 min.

10. A high-density beryllium-aluminum alloy prepared by the preparation method of the high-density beryllium-aluminum alloy according to any one of claims 1-9.