Post-treatment method for binder-high-temperature alloy mixed material green body

Abstract

The invention is suitable for the technical field of material treatment, and provides a post-treatment method for a binder-high-temperature alloy mixed material green body, and the post-treatment method specifically comprises the following steps: firstly, weighing a solvent; then, solvent circulation thermal degreasing is carried out; then, the tray and the palm blank are put into a ceramic container with the bottom paved with aluminum oxide landfill powder, meanwhile, aluminum oxide superfine powder starts to be paved from the edge of the container till the palm blank is completely buried by the powder, and the powder continues to be added till the powder is higher than the palm blank by a certain distance and the top face of the powder is horizontal; putting the ceramic container into a high-temperature atmosphere muffle furnace, heating to the melting point of the high-temperature alloy according to the speed of 1 DEG C / min in inert gas, keeping the temperature for 3 hours, and then naturally cooling; and finally, removing powder and taking pieces. The content of harmful gas in the subsequent degreasing link can be reduced, the mechanical property and size shrinkage uniformity of the green body are improved, and the problem of cracking or deformation of parts after sintering is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of material processing, and in particular to a post-processing method for a binder-high-temperature alloy mixed material green body. Background Art

[0002] High-temperature alloys are generally a series of alloys developed for high-temperature applications based on Group VIIIA elements and are widely used in gas turbines, rocket engines and the petrochemical industry. High-temperature alloys have good low-temperature ductility and excellent surface stability, and are the most important structural materials in high-temperature scenarios. Ni-based high-temperature alloys have good alloying ability and can be divided into different alloy systems, such as NiCr, Ni-Cr-Fe, etc. At the same time, the composition of different alloying elements makes Ni-based alloys in different working environments (such as corrosion, fatigue, high temperature, etc.) better in one or more properties. Therefore, Ni-based alloys are often used in thermal components in many key areas, such as blades, combustion chambers, turbine disks, etc.

[0003] Nickel-based superalloy components produced using laser additive manufacturing (AM) inevitably contain defects, which can affect the material's safe service life. Currently, the most commonly used AM technology is selective laser melting (MLM). Due to various instabilities during the forming process, such as drastic temperature fluctuations and a large molten pool solidification rate, the molded parts are prone to macroscopic defects such as warping, poor fusion, and cracking. Internal defects such as pores, lack of fusion, and cracks are also common. These defects severely reduce the overall performance of the molded parts and can even lead to damage and failure. Indirect AM can effectively reduce the drastic temperature fluctuations during the superalloy fusion process. However, the binder-superalloy green bodies produced by indirect AM often experience uneven shrinkage during post-processing processes such as degreasing and sintering due to non-metallic vaporization and release, as well as melting of the superalloy. These conditions can lead to cracking, deformation, and uneven shrinkage in the green bodies.

[0004] Therefore, in view of the above situation, there is an urgent need to develop a post-processing method that can be used for binder-high-temperature alloy hybrid green bodies to overcome the shortcomings in current practical applications. Summary of the Invention

[0005] The purpose of the embodiments of the present invention is to provide a post-processing method that can be used for a binder-high-temperature alloy mixed material green body, aiming to solve the problems raised in the above background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A post-processing method for a binder-high-temperature alloy mixed material green body comprises the following steps:

[0008] S1: Solvent weighing: Use an electronic balance to weigh the organic solvent in proportion to the mass of the binder-high-temperature alloy specimen green body;

[0009] S2: Solvent circulation thermal degreasing: Place the binder-high-temperature alloy mixed material green body on a hollow tray and place it in a circulating water bath heating kettle. Add the weighed organic solvent to the heating kettle, close the kettle, gradually heat to 75°C, keep warm for 12 hours, and then cool naturally. Then open the kettle and take out the tray and the corresponding brown body;

[0010] S3: Aluminum oxide filling: Place the tray and brown body into a ceramic container with aluminum oxide powder on the bottom. At the same time, add aluminum oxide ultrafine powder from the edge of the container until the powder completely covers the brown body. Continue adding powder until it is higher than the brown body by a certain distance and the top surface of the powder is level.

[0011] S4: High temperature densification: Place the ceramic container in a high temperature atmosphere muffle furnace, heat it to the melting point of the high temperature alloy at a rate of 1°C / min in an inert gas atmosphere, keep it at that temperature for 3 hours, and then cool it naturally.

[0012] S5: Clean powder and take out parts. Take out the ceramic container and use tools such as brushes and powder guns to take out the densified high-temperature alloy parts from the ceramic container, and further remove the residual aluminum oxide powder on the surface.

[0013] In a further technical solution, the organic solvent in S1 can be one or a mixture of acetone, ethyl acetate, and toluene.

[0014] A further technical solution is to continue adding powder in S2 until it is 3-5 cm higher than the brown body and the top surface of the powder is horizontal.

[0015] As a further technical solution, the hollow tray in S2 is made of silicon dioxide.

[0016] According to a further technical solution, the heating efficiency of the organic solvent in S2 is 1°C / min.

[0017] 1. The present invention only requires solvent degreasing before densification treatment, and no special carbon removal step is required;

[0018] 2. The degreasing solvent used in this scheme can be recycled through distillation and cooling without solvent consumption. Compared with the existing common thermal degreasing and inert gas powder non-landfill densification post-processing processes, the use of this method for binder-high-temperature alloy mixed material green body post-processing can effectively reduce the deformation, cracking and uneven dimensional shrinkage problems caused by high-temperature melting and unsupported conditions. It can also reduce the harmful gas content in the subsequent degreasing process, improve the mechanical properties and dimensional shrinkage uniformity of the green body, reduce the problems of cracking or deformation of parts after sintering, and at the same time, can prepare complex structures that cannot be manufactured due to thermal stress deformation.

[0019] In order to more clearly illustrate the structural features and effects of the present invention, the present invention is described in detail below with reference to the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the process of the present invention. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0022] The specific implementation of the present invention is described in detail below with reference to specific embodiments.

[0023] Example 1

[0024] like Figure 1 As shown, the present invention provides a post-processing method for a binder-high-temperature alloy mixed material green body, which specifically includes the following steps:

[0025] S1: Solvent weighing:

[0026] The mass of the binder-nickel-based alloy IN718 green strip obtained was 378.5 g, corresponding to a binder mass fraction of 5%. The required organic solvent acetone was 800 g, and 800 g of the organic solvent was weighed in proportion to the green strip mass using an electronic balance.

[0027] Preferably, the organic solvent can be one or a mixture of acetone, ethyl acetate, toluene.

[0028] S2: Solvent circulation thermal degreasing:

[0029] Place the binder-high-temperature alloy mixed material green body into a hollow tray and place it into a circulating water bath heating kettle. Add the organic solvent weighed in step S1 into the heating kettle, close the kettle body, gradually heat to 75°C, keep warm for 12 hours, and then cool naturally. Then open the kettle body, take out the tray and the corresponding green body, which is brown.

[0030] Preferably, the hollow tray is made of silicon dioxide, and the heating efficiency of the organic solvent is 1°C / min.

[0031] S3: Aluminum oxide landfill;

[0032] Place the tray and brown body into a ceramic container with alumina powder on the bottom. At the same time, add ultrafine alumina powder starting from the edge of the container until the powder completely covers the brown body. Continue adding powder until it is 3 cm higher than the brown body and the top surface of the powder is level.

[0033] S4: high temperature densification;

[0034] The ceramic container was placed in a high-temperature atmosphere muffle furnace, and the temperature was raised to 1260 degrees Celsius, the melting point of the high-temperature alloy IN718, at a rate of 1°C / min in an inert gas atmosphere, and kept at this temperature for 3 hours, followed by natural cooling.

[0035] S5: Clean powder and pick up items.

[0036] The ceramic container was taken out, and the densified nickel-based alloy IN718 specimen was taken out from the ceramic container using a brush, a powder blowing gun or other tools, and the residual aluminum oxide powder on the surface was further removed.

[0037] Example 2

[0038] like Figure 1 As shown, the present invention provides a post-processing method for a binder-high-temperature alloy mixed material green body, which specifically includes the following steps:

[0039] S1: Solvent weighing:

[0040] The mass of the manufactured binder-cobalt-based alloy K465 specimen green body is 124 g, corresponding to a binder mass fraction of 5%, and the required organic solvent acetone is 500 g. 500 g of the organic solvent is weighed in proportion to the mass of the green body using an electronic balance.

[0041] Preferably, the organic solvent can be one or a mixture of acetone, ethyl acetate, toluene.

[0042] S2: solvent circulation thermal degreasing;

[0043] Place the binder-high-temperature alloy mixed material green body into a hollow tray and place it into a circulating water bath heating kettle. Add the organic solvent weighed in step (S1) into the heating kettle, close the kettle body, gradually heat to 75°C, keep warm for 12 hours, and then cool naturally. Then open the kettle body and take out the tray and the corresponding brown body.

[0044] Preferably, the hollow tray is made of silicon dioxide, and the heating efficiency of the organic solvent is 1°C / min.

[0045] S3: Aluminum oxide landfill;

[0046] Place the tray and brown body into a ceramic container with the bottom covered with aluminum oxide powder. At the same time, start spreading aluminum oxide ultrafine powder from the edge of the container until the powder completely buries the brown body. Continue adding powder until it is 5 cm higher than the brown body and the top surface of the powder is level.

[0047] S4: high temperature densification;

[0048] The ceramic container was placed in a high-temperature atmosphere muffle furnace, and the temperature was raised to 1250 degrees Celsius, the melting point of the high-temperature alloy K465, at a rate of 1°C / min in an inert gas atmosphere, and kept at this temperature for 3 hours, followed by natural cooling.

[0049] S5: Clean powder and pick up items.

[0050] The ceramic container was taken out, and the densified cobalt-based alloy K465 specimen was taken out from the ceramic container using a brush, a powder blowing gun or other tools, and the residual aluminum oxide powder on the surface was further removed.

[0051] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A post-processing method for a binder-high-temperature alloy mixed material green body, characterized in that: The specific steps include: S1: Solvent weighing: Use an electronic balance to weigh the organic solvent in proportion to the mass of the binder-high-temperature alloy specimen green body; S2: Solvent circulation thermal degreasing: Place the binder-high-temperature alloy mixed material green body on a hollow tray and place it in a circulating water bath heating kettle. Add the weighed organic solvent to the heating kettle, close the kettle, gradually heat to 75°C, keep warm for 12 hours, and then cool naturally. Then open the kettle and take out the tray and the corresponding brown body; S3: Aluminum oxide filling: Place the tray and brown body into a ceramic container with aluminum oxide powder on the bottom. At the same time, add aluminum oxide ultrafine powder from the edge of the container until the powder completely covers the brown body. Continue adding powder until it is higher than the brown body by a certain distance and the top surface of the powder is level. S4: High temperature densification: Place the ceramic container in a high temperature atmosphere muffle furnace, heat it to the melting point of the high temperature alloy at a rate of 1°C / min in an inert gas atmosphere, keep it at that temperature for 3 hours, and then cool it naturally. S5: Clean powder and take out parts. Take out the ceramic container and use tools such as brushes and powder guns to take out the densified high-temperature alloy parts from the ceramic container, and further remove the residual aluminum oxide powder on the surface.

2. The post-processing method for binder-high temperature alloy mixed material green body according to claim 1, characterized in that: The organic solvent in S1 can be one or a mixture of acetone, ethyl acetate, and toluene.

3. The post-processing method for binder-high temperature alloy mixed material green body according to claim 1, characterized in that: Continue adding powder in S2 until it is 3-5 cm higher than the brown base and the top surface of the powder is level.

4. The post-processing method for binder-high temperature alloy mixed material green body according to claim 1, characterized in that: The hollow tray in S2 is made of silica.

5. The post-processing method for binder-high temperature alloy mixed material green body according to claim 1, characterized in that: The heating efficiency of the organic solvent in S2 is 1°C / min.

Images