Printing-state molten pool morphology corrosive liquid for 3D printing high-temperature alloy and application of printing-state molten pool morphology corrosive liquid

Abstract

The invention relates to a printing state molten pool morphology corrosive liquid for 3D printing high-temperature alloy and application thereof, in particular to the field of alloy morphology detection, and the printing state molten pool morphology corrosive liquid comprises hydrochloric acid, copper sulfate and water according to the mass ratio of (3-22): 1: (8-22). According to the printing state molten pool morphology corrosive liquid provided by the invention, by adopting a specific corrosive medium and utilizing positive and negative electrode electrolysis to accelerate corrosion of a grain boundary, it is ensured that the grain boundary is preferentially subjected to electrolytic corrosion without corroding the interior of the grain, the grain boundary contour of a metallographic sample is clearer, and particularly, the first cooling precipitated phases of the edge of the molten pool are minimum; an obvious contour boundary line is shown, and uniform electrolysis of the whole surface of the sample is realized.

Description

Technical Field

[0001] The present invention relates to the field of alloy morphology detection, and specifically to a 3D printed high-temperature alloy printed molten pool morphology etching liquid and its use, and in particular to a laser selective melting formed high-temperature alloy printed molten pool morphology etching liquid and its use. Background Art

[0002] At present, the laser selective melting forming technology is to laser sinter powder deposition layer by layer, and then stack them layer by layer to manufacture parts. The deposition plane and deposition increase direction, where the deposition plane is the laser scanning cross-section, the morphology is a strip shape, the deposition increase direction is the laser scanning longitudinal section, the shape of the molten pool is a semicircular arc morphology, the depth and width of the molten pool morphology can reflect the quality of the laser selective melting forming process parameters to a certain extent, and are often used for laser selective melting forming high-temperature alloy process parameter development data analysis, the corrosion molten pool morphology requires different corrosion effects on grains with different grain orientations, and shows the boundaries within the molten pool. Therefore, how to efficiently and conveniently etch out the deposition molten pool morphology of laser selective melting forming high-temperature alloys is very important.

[0003] Compared with traditional processing methods such as casting and forging, the structure has enough time to cool down, and the phases precipitate and form grain boundaries according to the different cooling speeds. These grain boundaries and precipitates can be well corroded during corrosion to form metallographic structure morphology. The laser selective melting process is a laser rapid melting of metal powder and rapid solidification. It has the characteristics of rapid melting and rapid solidification. Because the grains in the formed state are small and the precipitated phases are few, the composition in the structure is uniform, especially the boundary of the molten pool morphology. The first precipitated phases and grains are cooled rapidly and are also the smallest positions, resulting in the deposition state. The molten pool morphology structure is difficult to be corroded by chemical immersion corrosion.

[0004] The existing corrosion methods for high-temperature alloys mainly include immersion corrosion and electrolytic corrosion. However, for the corrosion of the molten pool morphology of high-temperature alloys prepared by laser selective melting forming technology, these two corrosion methods show different limitations.

[0005] For example, in immersion corrosion, the existing chemical immersion method loses the molten pool morphology even after the corrosion is organized, and it is easy to organize transition corrosion. Transition corrosion will make it difficult to achieve the observation effect of etching out the molten pool morphology.

[0006] For example, CN110644002A discloses a GH4648 high-temperature alloy weld metallographic etchant and corrosion method. The weld metallographic etchant includes 80 mL of concentrated nitric acid, 10-20 mL of hydrofluoric acid, and 20 mL of hydrogen peroxide; wherein the mass percentage concentration of concentrated nitric acid is 63%, the mass percentage concentration of hydrofluoric acid is 40%, and the mass percentage concentration of hydrogen peroxide is 30%. The configuration method is: first measure distilled water and add it to a beaker, then measure concentrated nitric acid and hydrofluoric acid and add them to a beaker, and finally, measure hydrogen peroxide and add it to a beaker. When using the etchant, the sample needs to be soaked for 2-5 minutes to obtain the best effect.

[0007] Another example is electrolytic corrosion. The formula of the electrolytic high-temperature alloy molten pool can be used, such as chromium oxide, hydrochloric acid, and water. However, chromium oxide is difficult to obtain and has a high cost. In addition, traditional electrolysis also immerses the sample in the corrosive solution, which is difficult and dangerous to operate. Moreover, this kind of electrolytic corrosion is prone to form a shielding effect at the edge of the sample when the positive and negative electrodes are immersed in the corrosive solution for electrolysis, resulting in only a small area of ​​the molten pool near the edge of the sample being corroded, and it is easy to over-corrode, which directly affects the observation of the entire sample surface. In addition, the traditional electrolysis method is unstable because the sample is soaked in the corrosive solution, and the corrosive solution is prone to volatilization of the acid, resulting in poor electrolysis effect. Summary of the invention

[0008] In view of the problems existing in the prior art, the purpose of the present invention is to provide a 3D printed high-temperature alloy printed molten pool morphology etching liquid and its use, so as to solve the defects of electrolytic instability and excessive corrosion in the electrolytic corrosion of the printed molten pool of the current 3D printed high-temperature alloy.

[0009] To achieve this object, the present invention adopts the following technical solutions:

[0010] In a first aspect, the present invention provides a printed molten pool morphology etching liquid for 3D printing high-temperature alloys, wherein the printed molten pool morphology etching liquid comprises:

[0011] Hydrochloric acid, copper sulfate and water in the mass ratio of (3-22):1:(8-22).

[0012] The printed molten pool morphology etching liquid provided by the present invention adopts a specific corrosive medium and utilizes positive and negative electrode electrolysis to accelerate the corrosion of grain boundaries, thereby ensuring that the grain boundaries are first electrolytically corroded without corroding the interior of the grains, thereby avoiding the occurrence of transitional corrosion, and achieving a clearer grain boundary contour of the metallographic sample, especially the edge of the molten pool is cooled first and the precipitated phase is the least, showing a more obvious contour boundary line, thereby achieving uniform electrolysis of the entire surface of the sample.

[0013] As a preferred technical solution of the present invention, the printed molten pool morphology etching solution comprises:

[0014] Hydrochloric acid, copper sulfate and water in a mass ratio of (4-6):1:(9-11).

[0015] As a preferred technical solution of the present invention, the printed molten pool morphology etching solution comprises:

[0016] Hydrochloric acid, copper sulfate and water in the mass ratio of (19-21):1:(19-21).

[0017] As a preferred technical solution of the present invention, the printed molten pool morphology etching solution comprises:

[0018] Hydrochloric acid, copper sulfate and water in a mass ratio of (4-6):1:(14-16).

[0019] In a second aspect, the present invention provides a use of the printed molten pool morphology etching solution as described in the first aspect, the use comprising:

[0020] The printed molten pool morphology etching liquid is used to electrolytically corrode the high-temperature alloy.

[0021] As a preferred technical solution of the present invention, the electrolytic corrosion includes: using the printed molten pool morphology corrosion liquid to cover the surface of the high-temperature alloy sample, and then the positive electrode contacts the edge of the high-temperature alloy sample and the negative electrode contacts the surface to be corroded.

[0022] As a preferred technical solution of the present invention, when the high-temperature alloy sample is an aging-hardened nickel-based high-temperature alloy, the printed molten pool morphology etching solution contains: hydrochloric acid, copper sulfate and water in a mass ratio of (4-6):1:(9-11).

[0023] Preferably, when the high-temperature alloy sample is a Ni-Cr based solid solution strengthened deformable high-temperature alloy, the printed molten pool morphology etching solution contains: hydrochloric acid, copper sulfate and water in a mass ratio of (19-21):1:(19-21).

[0024] Preferably, when the high-temperature alloy sample is a precipitation-hardened nickel-based high-temperature alloy, the printed molten pool morphology etching solution contains: hydrochloric acid, copper sulfate and water in a mass ratio of (4-6):1:(14-16).

[0025] As a preferred technical solution of the present invention, the electrolytic corrosion electrolysis voltage is 5-6.5V.

[0026] As a preferred technical solution of the present invention, the time for the negative electrode to contact the surface to be corroded is 2-5s.

[0027] As a preferred technical solution of the present invention, the distance between the positive electrode and the negative electrode is 5-10 mm.

[0028] Compared with the prior art solutions, the present invention has the following beneficial effects:

[0029] (1) The electrolyte concentration is low, the operation is safe, and there is no need to worry about excessive corrosion.

[0030] (2) The corrosion method is simple and easy to operate.

[0031] (3) The corrosion effect is good, and the molten pool morphology can be clearly corroded. In addition, different concentrations of corrosive liquid can be selected according to different corrosion resistance capabilities and different electrolytic pressures can be used to achieve molten pool corrosion of different alloys.

[0032] (4) The selected corrosive liquid material should be easy to obtain, safe and economical. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 The XZ and YZ plane photos of the printed microstructure and molten pool of the GH4169 alloy in Example 1 of the present invention are shown;

[0034] Figure 2 is a cross-sectional photograph of the printed microstructure of the GH4169 alloy in Example 1 of the present invention;

[0035] Figure 3 The XZ and YZ plane photos of the printed microstructure and molten pool of the GH3230 alloy in Example 2 of the present invention are shown;

[0036] Figure 4 This is a cross-sectional photo of the printed microstructure of the GH3230 alloy in Example 2 of the present invention.

[0037] Figure 5 The XZ and YZ plane photos of the printed microstructure and molten pool of the K438 alloy in Example 3 of the present invention are shown;

[0038] Figure 6 This is a cross-sectional photograph of the printed microstructure of the K438 alloy in Example 3 of the present invention.

[0039] The present invention is further described in detail below. However, the following examples are only simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims. DETAILED DESCRIPTION

[0040] To better illustrate the present invention and facilitate understanding of the technical solution of the present invention, typical but non-limiting embodiments of the present invention are as follows:

[0041] This embodiment provides a printed molten pool morphology etching liquid for 3D printing high-temperature alloys, and the printed molten pool morphology etching liquid comprises:

[0042] Hydrochloric acid, copper sulfate and water in the mass ratio of (3-22):1:(8-22).

[0043] In the present invention, the mass ratio limit of the printed molten pool morphology etching solution refers to the ratio limit of hydrochloric acid molecules, copper sulfate and solvent water in the solution.

[0044] In the present invention, the chloride ions in the etching solution form chloride on the metal surface to replace the oxide film on the surface, thereby accelerating the corrosion of the metal and enabling better corrosion. However, if sulfuric acid or nitric acid is used instead, since sulfuric acid and nitric acid do not have such a function, the corrosion effect will be affected, resulting in an unclear corrosion interface.

[0045] In the present invention, copper sulfate in the etching solution plays an irreplaceable role in electrolytic corrosion. When other sulfates such as iron sulfate or chromium sulfate are used as a substitute, the current density in the process will be affected, resulting in unclear grain boundary contours and uneven corrosion of the corrosion surface after electrolytic corrosion.

[0046] In the present invention, the preparation process of the printed molten pool morphology etching solution is as follows: ingredients are prepared according to the mass ratio and then mixed.

[0047] In the present invention, the printed molten pool morphology etching solution contains hydrochloric acid, copper sulfate and water in a mass ratio of (3-22):1:(8-22), for example, it can be 3:1:8, 4:1:9, 5:1:10, 6:1:11, 7:1:12, 8:1:13, 9:1:14, 10:1:15, 11:1:16, 12:1:17, 13:1:18, 14:1:19, 15:1:20, 16:1:21, 18:1:22, 20:1:20 or 5:1:15, but is not limited to the listed values, and other values ​​not listed within the range also meet the requirements.

[0048] Specifically, the printed molten pool morphology etching solution comprises:

[0049] The mass ratio of hydrochloric acid, copper sulfate and water is (4-6):1:(9-11), for example, it can be 4:1:9, 5:1:10, 6:1:11, 4:1:10, 4:1:11, 5:1:11 or 6:1:10, but is not limited to the listed values. Other values ​​not listed within this range also meet the requirements.

[0050] Specifically, the printed molten pool morphology etching solution comprises:

[0051] The mass ratio of hydrochloric acid, copper sulfate and water is (19-21):1:(19-21), for example, it can be 19:1:19, 20:1:20, 21:1:21, 19:1:20, 20:1:21, 21:1:19 or 20:1:19, but is not limited to the listed values. Other values ​​not listed within this range also meet the requirements.

[0052] Specifically, the printed molten pool morphology etching solution comprises:

[0053] The mass ratio of hydrochloric acid, copper sulfate and water is (4-6):1:(14-16), for example, it can be 4:1:14, 5:1:15, 6:1:16, 4:1:15, 5:1:14, 6:1:14, 5:1:16 or 6:1:15, but is not limited to the listed values. Other values ​​not listed in this range also meet the requirements.

[0054] Furthermore, the present invention provides the use of the printed molten pool morphology etching solution as described above, and the use includes:

[0055] The printed molten pool morphology etching liquid is used to electrolytically corrode the high-temperature alloy.

[0056] Specifically, the electrolytic corrosion includes: using the printed molten pool morphology corrosion liquid to cover the surface of the high-temperature alloy sample, and then the positive electrode contacts the edge of the high-temperature alloy sample, and the negative electrode contacts the surface to be corroded.

[0057] Specifically, when the high-temperature alloy sample is an aging-hardened nickel-based high-temperature alloy, the printed molten pool morphology etching solution contains: hydrochloric acid, copper sulfate and water in a mass ratio of (4-6):1:(9-11).

[0058] In the present invention, the nickel-based high temperature alloys such as GH4169 alloy and GH4099 alloy are aged and strengthened.

[0059] Specifically, when the high-temperature alloy sample is a Ni-Cr based solid solution strengthened deformable high-temperature alloy, the printed molten pool morphology etching solution contains: hydrochloric acid, copper sulfate and water in a mass ratio of (19-21):1:(19-21).

[0060] In the present invention, the Ni-Cr based solid solution strengthened deformable high temperature alloys include GH3230 alloy, GH3625 alloy, GH3536 alloy and the like.

[0061] Specifically, when the high-temperature alloy sample is a precipitation-hardened nickel-based high-temperature alloy, the printed molten pool morphology etching solution contains: hydrochloric acid, copper sulfate and water in a mass ratio of (4-6):1:(14-16).

[0062] In the present invention, the precipitation hardened nickel-based high temperature alloys include K438 alloy, K417 alloy, K447 alloy and the like.

[0063] Specifically, the electrolytic corrosion electrolysis voltage is 5-6.5V, for example, it can be 5V, 5.1V, 5.2V, 5.3V, 5.4V, 5.5V, 5.6V, 5.7V, 5.8V, 5.9V, 6V, 6.1V, 6.2V, 6.3V, 6.4V or 6.5V, but is not limited to the listed values, and other unlisted values ​​within the range also meet the requirements.

[0064] Specifically, the time for the negative electrode to contact the surface to be corroded is 2-5s, for example, it can be 2s, 2.5s, 3s, 3.5s, 4s, 4.5s or 5s, but is not limited to the listed values. Other values ​​not listed in this range also meet the requirements.

[0065] Specifically, the spacing between the positive electrode and the negative electrode is 5-10mm, for example, it can be 5mm, 5.5mm, 6mm, 6.5mm, 7mm, 7.5mm, 8mm, 8.5mm, 9mm, 9.5mm or 10mm, but is not limited to the listed values, and other unlisted values ​​within the range also meet the requirements.

[0066] Further, in order to illustrate that the printed molten pool morphology etching solution provided by the present invention can achieve a good electrolytic etching effect, the following actual example is used for illustration, as follows:

[0067] Example 1

[0068] This embodiment provides a printed molten pool morphology etching liquid for 3D printing high-temperature alloys, and the printed molten pool morphology etching liquid comprises:

[0069] Hydrochloric acid, copper sulfate and water in a mass ratio of 5:1:10.

[0070] The electrolytic corrosion process is as follows:

[0071] The surface of the high-temperature alloy sample (GH4169 alloy) is covered with the printed molten pool morphology etching solution, and then the positive electrode contacts the edge of the high-temperature alloy sample, and the negative electrode contacts the surface to be corroded;

[0072] The electrolytic voltage of the electrolytic corrosion is 5.5V; the time for which the negative electrode contacts the surface to be corroded is 2s; and the distance between the positive electrode and the negative electrode is 10mm.

[0073] The morphology and cross-sectional structure of the printed molten pool of GH4169 alloy are as follows: Figure 1 and Figure 2As shown in the figure, it can be seen that the boundary of the molten pool is well corroded, and the morphology cleaning shows a semicircular shape. The molten pools overlap each other, and there is an overlapping area between the left and right molten pools. The edge of the cross section is also clearly visible as a scanning line display. It can be seen that the scanning lines overlap each other, and at least three scanning lines with different scanning traces can be seen, and the dividing line is clearly visible.

[0074] Example 2

[0075] This embodiment provides a printed molten pool morphology etching liquid for 3D printing high-temperature alloys, and the printed molten pool morphology etching liquid comprises:

[0076] Hydrochloric acid, copper sulfate and water in a mass ratio of 20:1:20.

[0077] The electrolytic corrosion process is as follows:

[0078] The printed molten pool morphology etching solution is used to cover the surface of the high-temperature alloy sample (GH3230 alloy), and then the positive electrode contacts the edge of the high-temperature alloy sample, and the negative electrode contacts the surface to be corroded;

[0079] The electrolytic voltage of the electrolytic corrosion is 6V; the time for the negative electrode to contact the surface to be corroded is 3s; and the distance between the positive electrode and the negative electrode is 8mm.

[0080] The morphology and cross-sectional structure of the printed molten pool of GH3230 alloy are as follows: Figure 3 and Figure 4 As shown in the figure, it can be seen that the GH3230 alloy turns black after corrosion, but the molten pool morphology is still clearly visible, showing a semicircular shape, the cross-sectional scanning line outline is clearly visible, and the cross-sectional scanning lines of the two layers can be seen.

[0081] Example 3

[0082] This embodiment provides a printed molten pool morphology etching liquid for 3D printing high-temperature alloys, and the printed molten pool morphology etching liquid comprises:

[0083] Hydrochloric acid, copper sulfate and water in a mass ratio of 5:1:15.

[0084] The electrolytic corrosion process is as follows:

[0085] The surface of the high-temperature alloy sample (K438 alloy) is covered with the printed molten pool morphology etching liquid, and then the positive electrode contacts the edge of the high-temperature alloy sample, and the negative electrode contacts the surface to be corroded;

[0086] The electrolytic voltage of the electrolytic corrosion is 5V; the time for which the negative electrode contacts the surface to be corroded is 2s; and the distance between the positive electrode and the negative electrode is 10mm.

[0087] The morphology and cross-sectional structure of the K438 alloy printed molten pool are as follows: Figure 5and Figure 6 As shown in the figure, the morphology of the molten pool is clearly visible, the cross section is a little over-corroded but the edge is still clearly visible.

[0088] It can be seen from the results of the above embodiments that in the solution provided by the present invention, the molten pool structure can be well corroded by using hydrochloric acid, copper sulfate and aqueous solution in combination with different electrolysis pressures and times.

[0089] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0090] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0091] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A 3D printed high-temperature alloy molten pool morphology etching solution, characterized in that: The printed molten pool morphology etching solution comprises: Hydrochloric acid, copper sulfate and water in the mass ratio of (3-22):1:(8-22).

2. The printed molten pool morphology etching solution according to claim 1, characterized in that: The printed molten pool morphology etching solution comprises: Hydrochloric acid, copper sulfate and water in a mass ratio of (4-6):1:(9-11).

3. The printed molten pool morphology etching solution according to claim 1, characterized in that: The printed molten pool morphology etching solution comprises: Hydrochloric acid, copper sulfate and water in the mass ratio of (19-21):1:(19-21).

4. The printed molten pool morphology etching solution according to claim 1, characterized in that: The printed molten pool morphology etching solution comprises: Hydrochloric acid, copper sulfate and water in a mass ratio of (4-6):1:(14-16).

5. A use of the printed molten pool morphology etching solution as described in any one of claims 1 to 4, characterized in that: The uses include: The printed molten pool morphology etching liquid is used to electrolytically corrode the high-temperature alloy.

6. The use according to claim 5, characterized in that The electrolytic corrosion comprises: using the printed molten pool morphology corrosion liquid to cover the surface of the high-temperature alloy sample, and then the positive electrode contacts the edge of the high-temperature alloy sample, and the negative electrode contacts the surface to be corroded.

7. The use according to claim 5 or 6, characterized in that When the high-temperature alloy sample is an aging-strengthened nickel-based high-temperature alloy, the printed molten pool morphology etching solution comprises: hydrochloric acid, copper sulfate and water in a mass ratio of (4-6):1:(9-11); Preferably, when the high-temperature alloy sample is a Ni-Cr-based solid solution strengthened deformable high-temperature alloy, the printed molten pool morphology etching solution comprises: hydrochloric acid, copper sulfate and water in a mass ratio of (19-21):1:(19-21); Preferably, when the high-temperature alloy sample is a precipitation-hardened nickel-based high-temperature alloy, the printed molten pool morphology etching solution contains: hydrochloric acid, copper sulfate and water in a mass ratio of (4-6):1:(14-16).

8. The use according to any one of claims 5 to 7, characterized in that The electrolytic corrosion voltage is 5-6.5V.

9. The use according to any one of claims 6 to 8, characterized in that The negative electrode contacts the surface to be corroded for 2-5 seconds.

10. The use according to any one of claims 6 to 9, characterized in that The distance between the positive electrode and the negative electrode is 5-10 mm.

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