Injection molding preparation method of amorphous material
Through powder metallurgical injection molding technology and thermal isostatic sintering technology, combined with specific adhesive components and sintering technology, the problem of preparation of amorphous materials in the existing technology is solved, and the efficient preparation of complex structural amorphous materials is achieved and the mechanical properties of amorphous materials are guaranteed.
Patent Information
- Application Number
- CN202411765116.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-03
- Publication Date
- 2025-02-25
AI Technical Summary
It is difficult to effectively prepare large amorphous alloys, especially complex shapes of amorphous material products, because amorphous materials require high cooling rates and easily form crystalline phases, and traditional injection molding methods are difficult to achieve densification and prevent crystallization at high temperatures.
Powder metallurgical injection molding technology and thermal isostatic sintering technology are adopted to achieve the preparation of complex structural amorphous materials through feed preparation, injection molding, degreasing and presintering, thermal isostatic sintering and other steps, combined with specific adhesive components and sintering processes.
It realizes efficient preparation of complex structural amorphous materials, simple process, high material utilization rate, relatively low cost, suitable for mass production, avoids the occurrence of crystallization, and ensures the mechanical properties of the materials.
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Abstract
Description
Technical Field
[0001] The invention relates to a method for preparing an amorphous material, in particular to an injection molding method for an amorphous material. Background Art
[0002] Amorphous alloys have a unique atomic arrangement, which is short-range order but long-range disorder. This structure makes them immune to defects such as grain boundaries and dislocations, thus showing better mechanical properties than traditional crystalline alloys, such as high strength, high hardness and large elastic limit. However, the preparation of large amorphous alloys is very difficult because the amorphous formation ability is limited and the cooling rate is high. The internal cooling rate of large-sized products is slow, and it is very easy to form a crystalline phase. Therefore, it is extremely difficult to prepare large amorphous alloys by traditional methods and then make products of certain sizes and complex shapes through mechanical processing.
[0003] Injection molding is a molding method that can achieve large-scale, high-efficiency, and low-cost preparation of complex-shaped products. It can realize the one-time molding of powder raw materials by mixing with adhesives and then injecting them. The sintered products are the final required shape and size. For products with higher requirements, only a small amount of subsequent processing is required. In the prior art, the patent "2022106563175 Method for making slot needles for warp knitting machines and amorphous alloy injection molding process" involves injection molding technology, but the injection molding method used is not a traditional injection molding technology. It uses block raw materials, no adhesive, and the injection temperature is high, which has extremely high requirements for equipment. The crystallization temperature of amorphous materials is low, at about 450°C. To prevent crystallization, the sintering temperature is below the crystallization temperature and in the supercooled liquid phase above the glass transition temperature. The decomposition temperature of the feeding components of traditional injection molding is high. It can only be completely decomposed by keeping warm for a long time at a temperature above 400°C, but this temperature is already within the sintering temperature range, which will lead to incomplete degreasing and the material cannot be densified. In addition, long-term heat preservation is prone to crystallization, affecting performance. At present, there are few reports on the preparation of amorphous materials using metal injection molding. Combining amorphous materials with injection molding technology provides technical support for the preparation of complex parts made of amorphous materials and also provides a guarantee for the widespread application of amorphous materials. Summary of the invention
[0004] In order to solve the problems of the prior art, the present invention provides an injection molding method for amorphous materials, which comprehensively considers the characteristics and advantages of various adhesives, and combines them with injection molding technology and hot isostatic pressing sintering technology to achieve the preparation of amorphous products with complex structures.
[0005] In order to achieve the above object, the present invention adopts the following technical solution:
[0006] A preferred solution is a method for injection molding of an amorphous material, characterized by comprising the following steps:
[0007] A. Feed preparation: mix the amorphous powder and the binder evenly, the volume proportion of the powder is 55-65%, the mixing temperature is 170-180°C, and the mixing time is 1h;
[0008] B. Injection molding: the feed is made into granules and then injected into the required green body by an injection molding machine. The injection temperature is 185-195°C;
[0009] C. Degreasing and pre-sintering, removing the binder in the green body, and pre-sintering to obtain a certain strength;
[0010] D. Hot isostatic pressing sintering: the sintered blank is placed in a hot isostatic pressing furnace for further densification. The process is: 420-440℃ insulation for 20-40min, pressure 150-200Mpa, without a jacket.
[0011] In a preferred embodiment, the adhesive comprises the following components in a mass ratio: 50-60% polyoxymethylene POM, 20-30% polymethyl methacrylate PMMA, 15-25% polylactic acid PLA, 2-3% acetylcitrate tri-n-butyl ester ATBC, and 2-3% SA.
[0012] The preferred scheme is that the degreasing and pre-sintering method is carried out in two steps. The first step is catalytic degreasing, the catalyst is oxalic acid, and the catalytic temperature is 110-125°C. The second step is hot degreasing + pre-sintering. The process is to heat up to 270-280°C at 1-3°C / min, keep warm for 60-90min, then heat up to 300-350°C at 1-3°C / min, keep warm for 120-150min, and finally heat up to 400-420°C at 5-10°C / min, keep warm for 10-20min, and use Ar2 or N2 protection throughout the process.
[0013] In a preferred embodiment, the nominal atomic percentage composition of the amorphous powder is Zr 62 Cu 28 Al 10 , the powder particle size is not greater than 500 mesh.
[0014] In a preferred embodiment, the relative density of the prepared amorphous material is ≥96%.
[0015] Principles and advantages:
[0016] The present invention applies powder metallurgy injection molding technology and hot isostatic pressing sintering technology to the preparation of amorphous materials, thereby realizing the preparation of amorphous materials with complex structures, having a simple process, high material utilization rate, relatively low cost, and being suitable for mass production.
[0017] The selected adhesive components can all be removed at a relatively low temperature. POM, as the main component, can be decomposed into formaldehyde when it encounters acid above 110°C, and directly decomposes from the solid state to the gaseous state and is removed from the green body. It has good fluidity and shape retention, high stability in batch production, and is currently an ideal adhesive component. PMMA and PLA, as the skeleton components after the removal of POM, ensure that the subsequent product transfer has a certain strength, maintains the shape and size, and avoids defects. Their decomposition temperatures are relatively low. PMMA begins to decompose rapidly at 300°C, and PLA begins to decompose rapidly at 260-280°C. Both can be removed at a relatively low temperature without affecting the amorphous powder. In addition, the decomposition temperatures of the two adhesives are different, and the degreasing process is formulated accordingly, which is discharged in steps, with higher efficiency and less prone to defects. PMMA has good comprehensive mechanical properties, and its tensile, bending, and compression strengths are higher than those of polyolefins. PLA is a degradable, safe and environmentally friendly material. Its raw materials are mainly derived from renewable plant resources such as corn starch and sugarcane, and it has high strength characteristics. However, the brittleness of PLA increases. ATBC is added as a modifier to improve the toughness of PLA. The modified PLA has better toughness, so that the overall feed will not be too brittle under the influence of PLA and affect injection. In addition, ATBC also acts as a plasticizer, separating the internal molecules of the adhesive, reducing the attraction between molecules, and increasing the fluidity of the feed during injection. SA acts as a dispersant and lubricant to increase the uniformity of the feed and improve the injection conditions.
[0018] Hot isostatic pressing has high quality. During the sintering process, hot isostatic pressing applies high pressure to the material, evenly acting on the surface of the material, causing the powder to undergo plastic deformation and diffusion creep, promoting the discharge of pores, and thus, compared with traditional sintering, the material can be densified at a lower temperature to avoid crystallization of amorphous materials.
[0019] Among the selected amorphous components, each component is relatively cheap, has strong amorphous forming ability, and is suitable for mass production. DETAILED DESCRIPTION
[0020] The method of the present invention is further described below in conjunction with three embodiments.
[0021] Example 1
[0022] An injection molding method of an amorphous material comprises the following steps:
[0023] A. Feed preparation: Zr 62 Cu 28 Al 10The amorphous powder and the adhesive are mixed evenly, the volume ratio of the powder is 55%, the mixing temperature is 170°C, the mixing time is 1h, and the mass ratio composition of the adhesive is: 50% polyoxymethylene POM, 20% polymethyl methacrylate PMMA, 25% polylactic acid PLA, 3% acetylcitrate tri-n-butyl ester ATBC, and 2% SA;
[0024] B. Injection molding: the feed is made into granules and then injected into the required green body by an injection molding machine at an injection temperature of 185°C;
[0025] C. Debinding and pre-sintering. The debinding and pre-sintering are carried out in two steps. The first step is catalytic debinding. The catalyst is oxalic acid and the catalytic temperature is 110°C. The second step is thermal debinding + pre-sintering. The process is to heat up to 280°C at 3°C / min, keep it warm for 60min, then heat up to 350°C at 3°C / min, keep it warm for 120min, and finally heat up to 420°C at 10°C / min, keep it warm for 10min, and Ar2 protection is used throughout the process.
[0026] D. Hot isostatic pressing sintering: the sintered blank is placed in a hot isostatic pressing furnace for further densification. The process is: 430°C for 20 minutes, pressure 150 MPa, no jacket, and the relative density of the product is 96.5%.
[0027] Example 2
[0028] An injection molding method of an amorphous material comprises the following steps:
[0029] A. Feed preparation: Zr 62 Cu 28 Al 10 The amorphous powder and the adhesive are mixed evenly, the volume ratio of the powder is 60%, the mixing temperature is 175°C, the mixing time is 1h, and the mass ratio composition of the adhesive is: 55% polyoxymethylene POM, 25% polymethyl methacrylate PMMA, 15% polylactic acid PLA, 2% acetylcitrate tri-n-butyl ester ATBC, and 3% SA;
[0030] B. Injection molding: the feed is made into granules and then injected into the required green body by an injection molding machine, and the injection temperature is 190°C;
[0031] C. Debinding and pre-sintering. The debinding and pre-sintering are carried out in two steps. The first step is catalytic debinding. The catalyst is oxalic acid and the catalytic temperature is 120°C. The second step is thermal debinding + pre-sintering. The process is to heat up to 275°C at 2°C / min, keep it warm for 60min, then heat up to 300°C at 2°C / min, keep it warm for 150min, and finally heat up to 400°C at 10°C / min, keep it warm for 20min, and N2 protection is passed throughout the process.
[0032] D. Hot isostatic pressing sintering: the sintered blank is placed in a hot isostatic pressing furnace for further densification. The process is: 440°C for 30 minutes, pressure 150 MPa, no jacket, and the relative density of the product is 96.9%.
[0033] Example 3
[0034] An injection molding method of an amorphous material comprises the following steps:
[0035] A. Feed preparation: Zr 62 Cu 28 Al 10 The amorphous powder and the adhesive are mixed evenly, the volume ratio of the powder is 65%, the mixing temperature is 180°C, the mixing time is 1h, and the mass ratio composition of the adhesive is: 60% polyoxymethylene POM, 20% polymethyl methacrylate PMMA, 15% polylactic acid PLA, 2% acetylcitrate tri-n-butyl ester ATBC, and 3% SA;
[0036] B. Injection molding: the feed is made into granules and then injected into the required green body by an injection molding machine at an injection temperature of 195°C;
[0037] C. Debinding and pre-sintering. The debinding and pre-sintering are carried out in two steps. The first step is catalytic debinding. The catalyst is oxalic acid and the catalytic temperature is 125°C. The second step is thermal debinding + pre-sintering. The process is to heat up to 270°C at 1°C / min, keep it warm for 60 minutes, then heat up to 300°C at 1°C / min, keep it warm for 120 minutes, and finally heat up to 420°C at 5°C / min, keep it warm for 10 minutes, and use Ar2 or N2 protection throughout the process.
[0038] D. Hot isostatic pressing sintering: the sintered blank is placed in a hot isostatic pressing furnace for further densification. The process is: 430°C for 40 minutes, pressure 200 MPa, no jacket, and the relative density of the product is 98.0%.
[0039] Comparative Example 1
[0040] This comparative example adopts the same process steps as Example 3, except that the ratio of powder to adhesive is different, as shown in the following table.
[0041]
[0042] Comparative Example 2
[0043] This comparative example adopts the same process steps as Example 3, except that the powder is 200 mesh powder, resulting in a lower relative density of the product, which is only 92%.
[0044] Comparative Example 3
[0045] This comparative example adopts the same process steps as Example 3, except that the maximum pre-sintering temperature is 360° C. As a result, the relative density of the final product is relatively low, only 90%.
[0046] Comparative Example 4
[0047] This comparative example adopts the same process steps as Example 3, except that the hot isostatic pressing sintering process is different, as shown in the following table.
[0048]
[0049] The above-described examples are only preferred implementation methods of the present invention, and therefore cannot be used to limit the scope of implementation of the present invention. Other equivalent changes, modifications, substitutions and combinations made in accordance with the principles and contents of the present invention still fall within the protection scope of the present invention.
Claims
1. A method for injection molding of an amorphous material, characterized in that: It includes the following steps: A. Feed preparation: mix the amorphous powder and the binder evenly, the volume proportion of the powder is 55-65%, the mixing temperature is 170-180℃, and the mixing time is 1h; B. Injection molding: the feed is made into granules and then injected into the required green body by an injection molding machine. The injection temperature is 185~195℃; C. Degreasing and pre-sintering, removing the binder in the green body, and pre-sintering to obtain a certain strength; D. Hot isostatic pressing sintering: the sintered blank is placed in a hot isostatic pressing furnace for further densification. The process is: 420~440℃ insulation for 20~40min, pressure 150~200Mpa, without a jacket.
2. The injection molding method according to claim 1, characterized in that: The mass ratio composition of the adhesive is: 50~60% polyoxymethylene POM, 20~30% polymethyl methacrylate PMMA, 15~25% polylactic acid PLA, 2~3% acetylcitrate tri-n-butyl ester ATBC, and 2~3% SA.
3. The injection molding method according to claim 1, characterized in that: The debinding and pre-sintering method is carried out in two steps. The first step is catalytic debinding. The catalyst is oxalic acid and the catalytic temperature is 110~125℃. The second step is hot debinding + pre-sintering. The process is to heat up to 270~280℃ at 1~3℃ / min, keep warm for 60~90min, then heat up to 300~350℃ at 1~3℃ / min, keep warm for 120~150min, and finally heat up to 400~420℃ at 5~10℃ / min, keep warm for 10~20min, with Ar2 or N2 protection throughout the process.
4. The injection molding method according to claim 1, characterized in that: The atomic percentage composition of amorphous powder is Zr 62 Cu 28 Al 10 , the powder particle size is not greater than 500 mesh.
5. The injection molding method according to claim 1, characterized in that: The relative density of the prepared amorphous material is ≥96%.