CN117166037A - Electrolyte for IN-situ display of IN718 microstructure and EBSD characterization and method of use - Google Patents

Abstract

The invention provides an electrolyte for displaying I N718 microstructure and EBSD characterization in situ, which comprises metal chloride, concentrated hydrochloric acid, absolute ethyl alcohol and water; the mass ratio of the metal chlorides is 0.3% -6%; the mass ratio of the concentrated hydrochloric acid is 15-65%; the mass ratio of the water is 20% -65%; the mass ratio of the absolute ethyl alcohol is 10% -45%. According to the electrolyte for displaying the I N718 microstructure and the EBSD characterization in situ and the application method, the I N alloy sample prepared through ultra-fast electrochemical treatment not only maintains the microstructure characteristics generated in SLM molding, but also can be used as a sample for EBSD characterization without preparing the EBSD characterization crystal orientation again, the crystal orientation of the I N alloy sample can be observed in situ by observing the microstructure of the I N718 alloy sample, the relation among printing parameters, molten pool morphology and crystal orientation is quickly established, and important reference value is provided for alloy orientation regulation.

Description

Electrolyte for IN-situ display of IN718 microstructure and EBSD characterization and method of use

Technical Field

The invention belongs to the technical field of alloy analysis, and particularly relates to an electrolyte for IN-situ display of IN718 microstructure and EBSD characterization and a use method thereof.

Background

In recent years, additive manufacturing technology has rapidly developed, on one hand, the additive manufacturing technology breaks the limitation of traditional manufacturing, so that objects with complex shapes and structures can be designed and manufactured in a more free and innovative manner, which provides a product designer with greater freedom, promotes realization of personalized custom manufacturing, and meets the requirements of individual demands and specific applications. Additive manufacturing, on the other hand, provides a new approach to optimizing material structure and performance. The grain structure, phase content and texture of the material can be regulated by controlling the printing parameters, heat treatment, subsequent processing and other technological measures, so as to realize optimized mechanical property, thermal property, corrosion resistance and the like. This is of great importance for developing new materials and improving the properties of existing materials.

Superalloy IN718 has excellent high temperature strength, heat resistance and corrosion resistance and is therefore widely used IN many fields. The IN718 alloy is one of the most commonly used superalloys IN the aerospace industry. It is widely used to manufacture critical components of aircraft engines, such as turbine blades, turbine disks, combustor assemblies, and the like. However, under the high temperature condition, the IN718 alloy is continuously deformed under the stress, which is the creep phenomenon. The study found that the lower the number of grain boundaries IN the IN718 sample, the better the creep resistance, i.e. the stronger the texture, the better the creep resistance. There is an increasing number of studies reporting the control of the texture of IN718 using additive manufacturing techniques, which have found that the size, morphology, solidification rate and solidification pattern of the melt pool formed during additive manufacturing are related to the texture of the final part. This inevitably leads to observations of the melt pool morphology and size of the additive manufacturing IN718, and the size and growth pattern of the solidifying dendrites, and the observation of texture provides guidance for process optimization of the additive manufacturing process.

Although many methods for observing the morphology of a molten pool by chemical corrosion are reported at present, the corrosion time is generally long and is not well controlled by adopting a chemical corrosion method, and the method is easy to be corroded excessively, and if the EBSD analysis crystal orientation is required to be observed in situ for the corroded sample, the sample needs to be prepared again, the sample preparation period is long, and the sample preparation is complicated, so that the improvement is necessary.

Disclosure of Invention

The invention aims to overcome the defects of the prior art, and provides an electrolyte for displaying an IN718 microstructure and EBSD characterization IN situ and a use method thereof, wherein the prepared IN718 alloy sample not only maintains the microstructure characteristics generated IN the additive manufacturing process, but also can be used for EBSD observation, does not need to prepare a sample again for the EBSD observation, and is beneficial to guiding alloy orientation regulation and control by establishing the relation among printing parameters, molten pool morphology and crystal orientation.

The technical scheme of the invention is as follows: an electrolyte for IN situ display of IN718 microstructure and EBSD characterization, the electrolyte comprising metal chloride, concentrated hydrochloric acid, absolute ethanol, and water; the mass ratio of the metal chlorides is 0.3% -6%; the mass ratio of the concentrated hydrochloric acid is 15% -65%; the mass ratio of the water is 20% -65%; the mass ratio of the absolute ethyl alcohol is 10% -45%.

As a further improvement of the technical scheme, the metal chloride is cupric chloride which is formed by dissolving copper chloride dihydrate crystals or cupric chloride powder; the water is deionized water.

As a further improvement of the technical scheme, the electrolyte comprises 1-4 g of copper chloride dihydrate, 20-50 ml of concentrated hydrochloric acid, 20-50 ml of absolute ethyl alcohol and 30-60 ml of deionized water.

As a further improvement of the technical scheme, the concentration of the concentrated hydrochloric acid is 36-38%.

The invention also provides a use method of the electrolyte, which comprises the following steps:

preparing an anode electrode, polishing or polishing an IN718 alloy sample until no obvious scratch exists, cleaning the surface and drying to obtain a sample to be tested serving as the anode electrode;

preparing a cathode electrode;

electrolytic corrosion is carried out, wherein a sample to be tested and a cathode electrode are respectively connected with a power supply and are placed in the electrolyte, and electrolytic corrosion is carried out after power is supplied;

and (5) polishing, namely cleaning and drying the sample to be tested after electrolytic corrosion.

As a further improvement of the technical scheme, IN the step of preparing the anode electrode, sand paper is adopted to polish the surface of the IN718 alloy to be tested, and diamond grinding paste is adopted to polish.

As a further improvement of the technical scheme, the granularity of the sand paper is 100-2000 meshes; and/or the diamond powder granularity in the diamond grinding paste is 1.5-3.5 mu m.

As a further improvement of the technical scheme, in the electrolytic corrosion step, the power supply is a direct-current power supply and adopts an output mode of constant-current output.

As a further improvement of the technical scheme, the output voltage of the power supply is 10V-15V.

As a further improvement of the technical scheme, in the electrolytic corrosion step, the electrolytic corrosion time is 8-25 s.

The electrolyte for IN-situ display of IN718 microstructure and EBSD characterization provided by the invention comprises metal chloride, concentrated hydrochloric acid, absolute ethyl alcohol and water; the mass ratio of the metal chlorides is 0.3% -6%; the mass ratio of the concentrated hydrochloric acid is 15% -65%; the mass ratio of the water is 20% -65%; the mass ratio of the absolute ethyl alcohol is 10% -45%. The invention also provides a use method of the electrolyte, the electrolyte is adopted, the IN718 alloy sample prepared by ultra-fast electrochemical treatment not only reserves the microstructure characteristics generated IN the additive manufacturing process, but also can be used as an EBSD characterization sample at the same time without preparing the EBSD characterization crystal orientation again, the microstructure of the IN718 alloy sample is mainly a molten pool and a solidification dendrite structure, the crystal orientation of the IN718 alloy sample can be observed IN situ (namely, the corresponding position of the microstructure is observed), the relation among printing parameters, the molten pool morphology and the crystal orientation is quickly established, and important reference value is provided for SLM IN718 alloy orientation regulation and control, so that alloy orientation regulation and control is guided; compared with the traditional corrosion method (generally, non-powered soaking corrosion), the method has higher efficiency, and can display solidification structure, molten pool morphology and crystal orientation information at the same time.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 (a) is a microstructure obtained by scanning a sample surface 1-1# which is subjected to immersion etching for 6min in example 3 of the present invention;

FIG. 1 (b) is a microstructure obtained by scanning electron microscope scanning of the surface of a 1-2# sample subjected to immersion etching for 7min provided in example 3 of the present invention;

FIG. 2 (a) is a sample of IN718 alloy (sample # 2, corresponding to # 1-1) provided with electrochemical corrosion according to example 4 of the present invention with a low-power bath morphology on the surface;

FIG. 2 (b) shows the high-power molten pool morphology of the surface of an IN718 alloy sample (sample # 2, corresponding to # 1-1) electrochemically etched IN accordance with example 4 of the present invention;

FIG. 2 (c) is an EBSD plot of an electrochemically etched IN718 alloy sample (sample # 2, corresponding to # 1-1) of example 4 of the present invention;

FIG. 2 (d) is an IN situ grain boundary analysis of an electrochemically etched IN718 alloy sample (sample # 2, corresponding to # 1-1) according to example 4 of the present invention;

FIG. 3 (a) is a sample of IN718 alloy (sample # 3, corresponding to # 1-2) provided with electrochemical corrosion according to example 5 of the present invention with a low-power bath morphology on the surface;

FIG. 3 (b) shows the high-power molten pool morphology of the surface of an IN718 alloy sample (sample # 3, corresponding to # 1-2) electrochemically etched IN accordance with example 5 of the present invention;

FIG. 3 (c) is an EBSD plot of an electrochemically etched IN718 alloy sample (sample # 3, corresponding to # 1-2) of example 5 of the present invention;

FIG. 3 (d) is an IN situ grain boundary analysis of an electrochemically etched IN718 alloy sample (sample # 3, corresponding to # 1-2) according to example 5 of the present invention.

Detailed Description

The present invention will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.

It should be noted that the terms "disposed" and "connected" should be construed broadly, and may be, for example, directly disposed or connected, or indirectly disposed or connected through a central element or a central structure.

In addition, in the embodiments of the present invention, terms of directions or positional relationships indicated by "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., are directions or positional relationships based on the directions or positional relationships shown in the drawings or the conventional placement state or use state, are merely for convenience of describing the present invention and simplifying the description, and do not indicate or imply that the structures, features, devices or elements to be referred to must have specific directions or positional relationships nor must be constructed and operated in specific directions, and thus should not be construed as limiting the present invention. In the description of the present invention, unless otherwise indicated, the meaning of "a plurality" is two or more.

The various features and embodiments described in the detailed description may be combined in any suitable manner, for example, different embodiments may be formed by different combinations of features/embodiments, where not contradictory, and various possible combinations of features/embodiments in the present invention are not described further in order to avoid unnecessary repetition.

Example 1

The present embodiment provides an electrolyte for IN-situ display of IN718 microstructure and EBSD characterization, IN718 alloy by SLM forming (a forming technique of 3D printing, also known as selective laser melting or rapid prototyping technique or additive manufacturing), comprising metal chloride, concentrated hydrochloric acid, absolute ethanol and water; the mass ratio of the metal chlorides is 0.3% -6%; the mass ratio of the concentrated hydrochloric acid is 15% -65%; the mass ratio of the water is 20% -65%; the mass ratio of the absolute ethyl alcohol is 10% -45%. In the present invention, the mass ratio means the mass ratio of the substance in the electrolyte.

The metal chloride can be copper chloride, zinc chloride, ferric chloride and the like, needs to be selected by combining cathode materials in electrolysis, uses low-activity metal chloride, avoids metal ions dissolved in electrolyte to participate in electrolysis reaction, and takes account of environmental protection, safety and cost factors. Copper chloride is selected in the embodiment, and can be formed by dissolving copper chloride dihydrate crystals or copper chloride powder. In the embodiment, the cupric chloride is formed by dissolving a copper chloride dihydrate crystal, the copper ion activity is low, the copper chloride dihydrate is easy to obtain and dissolve, the copper chloride dihydrate crystal is safe to use in experiments, and the waste is environment-friendly; in some embodiments, the purity of the copper chloride dihydrate is not less than 99% so as to avoid excessive impurities affecting the etching solution. In this embodiment, the mass ratio of the copper chloride dihydrate is 0.5% -5.5%. In other examples, copper chloride powder may be dissolved, or copper chloride powder and copper chloride dihydrate crystal may be mixed and dissolved, and the added weight may be adjusted to convert the same mass ratio as that of the copper chloride dihydrate of this example, so that the substantial effect (copper ion and chloride ion concentration in the solution) is the same as that of the present invention, and the present invention is also within the scope of the present invention.

For the water, the water is deionized water, and the mass ratio of the deionized water is 22% -60%; in other embodiments, distilled water, pure water, high purity water, ultrapure water, or the like may be used, and the deionized water used in the present embodiment can reduce impurities (hydrogen ions, or the like) in the electrolyte and is low in cost.

For the absolute ethyl alcohol, the mass ratio of the absolute ethyl alcohol is 11% -42%; in this embodiment, the concentration of the absolute ethanol solution is not less than 99.7%.

For the concentrated hydrochloric acid, the concentration of the concentrated hydrochloric acid is 36% -38%; in this embodiment, the mass ratio of the concentrated hydrochloric acid is 18% -61%.

In some embodiments, the electrolyte comprises a corrosive solution obtained by mixing 1-4 g of copper chloride dihydrate, 20-50 ml of concentrated hydrochloric acid, 20-50 ml of absolute ethyl alcohol and 30-60 ml of deionized water; in a specific application, the concentrated hydrochloric acid is poured into the copper chloride dihydrate and stirred until the copper chloride dihydrate is completely dissolved; adding absolute ethyl alcohol and deionized water, and uniformly mixing to obtain corrosive liquid; in this embodiment, 30ml of concentrated hydrochloric acid is poured into 2g of copper chloride dihydrate, stirred until the copper chloride dihydrate is completely dissolved, and then 30ml of absolute ethyl alcohol and 50ml of deionized water are added, all the raw materials are uniformly mixed, and it is to be noted that the effects of the corrosive liquid with the same proportion (for example, the same mass ratio of each additive substance) of each additive substance, such as 2-8 g of copper chloride dihydrate, 40-100 ml of concentrated hydrochloric acid, 40-100 ml of absolute ethyl alcohol and 60-120 ml of deionized water, are substantially the same as those of this embodiment, and the effects of the corrosive liquid with the same proportion are also within the protection range; in the embodiment, only a few raw materials are needed, the proportion is simple, and compared with the traditional corrosion method (generally, non-powered soaking corrosion) adopted by adopting the electrochemical corrosion method, the corrosion liquid in the embodiment has higher efficiency, and can display solidification structure, molten pool morphology and crystal orientation information at the same time.

The electrolytic solution IN this example was used to electrochemically etch the IN718 alloy, and the specific method of use can be seen IN example 2.

Example 2

The embodiment provides a use method of the electrolyte, which can be used for displaying an IN718 microstructure and used for EBSD characterization; wherein the IN718 alloy was shaped by SLM using the electrolyte of example 1, the method of use includes the steps of preparing an anode electrode, preparing a cathode electrode, electrolytic etching, and post-polishing treatment.

The electrolyte adopted in the embodiment is obtained by pouring concentrated hydrochloric acid into copper chloride, stirring until the copper chloride dihydrate is dissolved, and then adding absolute ethyl alcohol and deionized water for mixing; specifically, 20-50 ml of concentrated hydrochloric acid is poured into copper chloride dihydrate (1-4 g), stirred until the copper chloride dihydrate is completely dissolved, then 20-50 ml of absolute ethyl alcohol and 30-60 ml of deionized water are added, and all the raw materials are uniformly mixed to prepare the electrolyte.

IN the step of preparing the anode electrode, an IN718 alloy sample is polished or polished until no obvious scratch exists, the surface is cleaned and dried, and a sample to be detected is obtained; IN this example, the sample to be tested of the IN718 alloy was surface polished with sandpaper and polished with a diamond paste. The granularity of the sand paper is 100-2000 meshes; the diamond powder in the diamond grinding paste has a granularity of 1.5-3.5 mu m (2.5 mu m is preferable in the embodiment); specifically, the sample to be polished is manually polished, 100-2000 mesh sand paper is adopted to polish the surface of the IN718 alloy sample, 2.5 mu m diamond grinding paste is used for manually polishing until no obvious scratch exists, and clean water is adopted to clean and blow-dry the surface, so that the sample to be polished can be used as an anode electrode.

Wherein, in the step of preparing the cathode electrode, an inert metal such as a metal platinum sheet or SUV304 stainless steel material is used as the cathode electrode.

In the electrolytic corrosion step, a sample to be tested and a cathode electrode are respectively connected with a power supply and are placed in the electrolyte (electrolyte), and electrolytic corrosion is carried out after power is applied; during electrochemical corrosion, the surface to be corroded of the sample to be tested is opposite to (or approximately opposite to) the surface of the cathode electrode, namely the surface to be corroded of the IN718 alloy sample should be ensured to be opposite to the surface (platinum sheet surface) of the cathode electrode; in a specific application, the using method further comprises a marking step, wherein a sharp tool (such as tweezers) can be used for marking at any position on the surface of the sample (the size and position of the scratch can be selected according to actual needs), so that the crystal orientation of the subsequent EBSD characterization is characterized in situ (the same position of the observed microstructure). More specifically, the electrolysis time is 8-25 s, in this embodiment, the electrolysis is only needed for 12s, in other embodiments, the electrolysis is needed for 16s, and the specific electrolysis time can be selected according to the surface size of the sample.

In the polishing post-treatment step, the sample to be tested after electrolytic corrosion is cleaned by ultrasonic and immediately dried. The sample after electrolytic corrosion needs to be cleaned by ultrasonic in time to prevent residual corrosive liquid from corroding the surface of the sample to be tested; in this example, the electrolytic etching temperature was 22 to 25℃at room temperature.

In the electrolytic corrosion step, the power supply is a direct current power supply and adopts an output mode of constant current output, and is generally set to be 0.5-3A, in this embodiment, the output voltage of the sample to be tested is 10-15V, the specific output voltage value is determined by the size of the sample, and the voltage value changes between 10-15V.

The traditional chemical corrosion method generally adopts strong acid corrosion liquid, the required corrosion time is generally longer, the control is not good, the corrosion is easy to overstock, the electrolyte IN the embodiment 1 is adopted, IN the embodiment, the IN718 alloy sample is subjected to electrochemical corrosion, the surface of the sample is treated, the ultra-rapid corrosion of the surface of the IN718 alloy sample is realized, the metallographic observation of a scanning electron microscope can be carried out on the SLM formed IN718 sample subjected to the electrolytic corrosion, and the microstructure characteristics generated IN the SLM forming process are reserved, namely a molten pool and solidification dendrites; on the other hand, the IN718 sample subjected to electrochemical corrosion polishing IN the embodiment can be simultaneously used as a sample represented by EBSD (electron back scattering diffraction, electron Backscatter Diffraction), namely, the surface of the sample meets the surface requirement of the EBSD represented sample, and the preparation of the EBSD represented crystal orientation re-sample is not needed, generally, the preparation of the IN718 alloy EBSD sample generally comprises (1) complicated mechanical grinding and vibration polishing with a certain amplitude for more than 6 hours, and the situation that corrosion products are embedded into the sample easily occurs due to over-polishing, so that the surface topography observation is influenced; (2) electrochemical polishing: the method generally selects acid corrosive liquid with strong corrosiveness, such as concentrated sulfuric acid, perchloric acid and the like, and the prepared solution has high danger coefficient, is not easy to control polishing time and is easy to cause over polishing. The above two EBSD sampling methods can observe the crystal orientation, but cannot observe the solidification structure and the molten pool morphology. Through the electrochemical corrosion method IN the embodiment, when the microstructure of the IN718 alloy sample is observed, mainly a molten pool and a solidified dendrite structure, and the crystal orientation of the IN718 alloy sample can be observed IN situ (namely the same position of the microstructure is observed), the stress layer generated by mechanical cutting or polishing and the like on the surface of the alloy sample can be removed due to the introduction of the electrochemical method, and the specific mechanism is as follows: electrochemical polishing is a commonly used surface treatment method for removing a stress layer on the surface of a sample; the mechanism involves electrochemical reactions and electron transfer processes in the electrolyte solution. In electrochemical polishing, a sample is placed in an electrolyte solution, and a voltage or current is applied as an anode or cathode. When a voltage or current is applied, oxidation and reduction reactions occur. In general, when the sample is used as an anode, an oxidation reaction occurs, and when the sample is used as a cathode, a reduction reaction occurs; in the oxidation reaction, metal ions on the sample surface are oxidized to metal ions and dissolved into the electrolyte solution. This process is known as anodic dissolution. By dissolving the metal ions, the stress layer originally existing on the surface of the sample is removed; in the reduction reaction, the oxidizing agent or reducing agent in the electrolyte solution is reduced or oxidized. This process can occur at the cathode or can occur in solution by metal ions generated at the anode. The reduction reaction may consume some of the metal ions in the electrolyte solution, thereby replenishing the metal ions consumed by the anodic dissolution to maintain charge balance. By controlling the magnitude and time of the voltage or current, the rate of anodic dissolution and the extent of the reduction reaction can be controlled. Therefore, the stress layer on the surface of the sample can be accurately removed, so that the sample is smoother; therefore, besides observing the appearance of a molten pool, a strong diffraction pattern can be obtained, the relation among printing parameters, the appearance of the molten pool and crystal orientation is quickly established, an important reference value is provided for SLM IN718 alloy orientation regulation and control, and the regulation and control of the IN718 alloy orientation is favorably guided; compared with the traditional corrosion method (generally, non-powered soaking corrosion), the method has higher efficiency, and can display solidification structure, molten pool morphology and crystal orientation information at the same time.

Examples 3, 4, 5 are also provided as a comparison.

Example 3 (as comparative example)

Mechanically cutting the surface of an SLM molded IN718 sample, polishing the surface of the sample by adopting 100-2000 mesh sand paper, manually polishing by using 2.5 mu m diamond grinding paste until no obvious scratch exists, cleaning the surface with clear water, and drying to obtain two samples No. 1 (1-1 # and 1-2 #). Then carrying out ordinary soaking corrosion on a mechanically polished IN718 sample (sample No. 1), putting the prepared IN718 sample into a corrosive liquid (specifically, pouring 50ml of concentrated hydrochloric acid into 4g of copper chloride dihydrate, stirring until the copper chloride dihydrate is completely dissolved, adding 50ml of absolute ethyl alcohol and 45ml of ionized water, and uniformly mixing to obtain the corrosive liquid), wherein the corrosion temperature is 25 ℃, and the corrosion time of the two samples No. 1 is 6min (sample No. 1) and 7min (sample No. 1-2) respectively. And (3) sequentially putting the corroded sample No. 1 into alcohol and deionized water, respectively ultrasonically cleaning for 3 minutes, and drying and storing. As shown IN fig. 1, IN which fig. 1 (a) is a surface of an IN718 sample (sample 1-1 #) subjected to immersion etching for 6min, and fig. 1 (b) is a surface of an IN718 sample (sample 1-2 #) subjected to immersion etching for 7min, it is clear from the results that the effect of the sample surface after etching with a mixed solution of copper chloride dihydrate, hydrochloric acid, absolute ethanol, deionized water for various times is insignificant, and only some grain morphology contrast, and no molten pool characteristics, can be observed.

Example 4

In order to compare the corrosion condition of the sample in fig. 1 (a) in example 3, the sample in this example 4 was subjected to electrochemical treatment as in example 3.

Mechanically cutting the surface of an SLM molded IN718 sample, polishing the surface of the sample by adopting 100-2000 mesh sand paper, manually polishing by adopting 2.5 mu m diamond grinding paste until no obvious scratch exists, cleaning and drying the surface by adopting clear water to obtain a sample No. 2, wherein the obtained sample No. 2 is the same as the sample No. 1 IN the embodiment 3. Then carrying out electrolytic corrosion on a mechanically polished IN718 sample (sample No. 2), wherein the cathode material is a metal platinum sheet, pouring electrolyte (the specific proportion is that 50ml of concentrated hydrochloric acid is poured into 4g of copper chloride dihydrate, stirring is carried out until the copper chloride dihydrate is completely dissolved, then 50ml of absolute ethyl alcohol and 45ml of ionized water are added, and the mixture is uniformly mixed to obtain corrosion solution), setting the electrolytic corrosion current of a direct current power supply of 1A, and the electrolytic corrosion temperature of the direct current power supply is 25 ℃ and the electrolytic corrosion time of the direct current power supply of 12s. And (3) putting the sample No. 2 subjected to electrolytic corrosion into alcohol and deionized water in sequence, carrying out ultrasonic cleaning for 3 minutes, and drying and storing. FIG. 2 is an electrolytically etched SLM molded IN718 sample surface microstructure or crystal orientation, wherein FIG. 2 (a) is a low power bath topography; FIG. 2 (b) is a high-power bath topography; FIG. 2 (c) in situ EBSD map; FIG. 2 (d) in-situ grain boundary analysis. From the results of the IN situ (same position) surface analysis diagrams of the IN718 alloy sample surface shown IN fig. 2 (b), 2 (c) and 2 (d), it is known that the surface quality of the SLM formed IN718 alloy sample by electrolytic corrosion according to the embodiment of the invention is good, the EBSD diagram with high quality can be obtained while the characteristics of the molten pool can be clearly observed, the characteristics of the grain boundary (shown IN fig. 2 (d)) are analyzed, the relationship between the molten pool morphology and the crystal orientation distribution of the IN718 alloy sample is obtained, and the relationship among the printing parameters, the molten pool morphology and the crystal orientation is established, which is significant for guiding the regulation of the orientation of the SLM formed IN718 alloy.

Example 5

In order to compare the corrosion of the sample in fig. 1 (b) in example 3, the sample identical to that in example 3 was electrochemically treated using the above-described electrolyte as an electrolyte in this example 5.

Mechanically cutting the surface of an SLM molded IN718 sample, polishing the surface of the sample by adopting 100-2000 mesh sand paper, manually polishing by adopting 2.5 mu m diamond grinding paste until no obvious scratch exists, and cleaning and drying the surface by adopting clear water to obtain a sample No. 3. Then carrying out electrolytic corrosion on a mechanically polished IN718 sample (sample 3#) with a metal platinum sheet as a cathode material, pouring an electrolytic corrosion solution (specifically, 50ml of concentrated hydrochloric acid is poured into 4g of copper chloride dihydrate, stirring is carried out until the copper chloride dihydrate is completely dissolved, then 50ml of absolute ethyl alcohol and 45ml of ionized water are added, and uniformly mixing to obtain the corrosion solution), setting an electrolytic corrosion current 1A, wherein the electrolytic corrosion temperature is 25 ℃, and the electrolytic corrosion time is 16s. And (5) sequentially putting the sample subjected to electrolytic corrosion into alcohol and deionized water, respectively carrying out ultrasonic cleaning for 3 minutes, and drying and storing. FIG. 3 shows the surface microstructure or crystal orientation of an electrolytically etched SLM molded IN718 sample (sample 3#), FIG. 3 (a) a low power bath topography; FIG. 3 (b) high-power bath topography; FIG. 3 (c) in situ EBSD map;

FIG. 3 (d) in-situ grain boundary analysis. FIGS. 3 (b), 3 (c) and 3 (d) are surface analysis diagrams of the same position on the sample surface, so that the electrolytic corrosion additive manufacturing IN718 sample has good surface quality, the characteristics of a molten pool can be clearly observed, and meanwhile, a high-quality EBSD (electron beam diffraction) diagram can be obtained, and the characteristics of a grain boundary (as shown IN FIG. 3 (d)) are analyzed to obtain the relationship between the molten pool form and the crystal orientation distribution of an alloy sample; compared with the embodiment 4, IN a certain time range, more obvious molten pool morphology and clearer crystal orientation can be observed through electrochemical corrosion for a longer time, IN other embodiments, different time can be corroded, and the relationship between the molten pool morphology and the crystal orientation of an IN718 sample with different corrosion time under other conditions can be obtained, or the relationship between the molten pool morphology and the crystal orientation of a sample to be detected reflected by different electrolyte with the same corrosion time is obtained.

The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, or alternatives falling within the spirit and principles of the invention.

Claims (10)

1. Electrolyte for IN-situ display of IN718 microstructure and EBSD characterization, characterized IN that the electrolyte comprises metal chloride, concentrated hydrochloric acid, absolute ethanol and water; the mass ratio of the metal chlorides is 0.3% -6%; the mass ratio of the concentrated hydrochloric acid is 15% -65%; the mass ratio of the water to the water is 20% -65%; the mass ratio of the absolute ethyl alcohol is 10% -45%.

2. The electrolyte of claim 1, wherein the metal chloride is cupric chloride, the cupric chloride being formed by dissolving cupric chloride dihydrate crystals or cupric chloride powder; the water is deionized water.

3. The electrolyte of claim 2, wherein the electrolyte comprises 1-4 g of copper chloride dihydrate, 20-50 ml of concentrated hydrochloric acid, 20-50 ml of absolute ethyl alcohol, and 30-60 ml of deionized water.

4. The electrolyte of claim 1 wherein the concentrated hydrochloric acid has a concentration of 36% to 38%.

5. A method of using the electrolyte according to any one of claims 1 to 4, comprising the steps of:

preparing an anode electrode, polishing an IN718 alloy sample to be tested, cleaning the surface and drying to obtain the sample to be tested serving as the anode electrode;

preparing a cathode electrode;

electrolytic corrosion is carried out, wherein a sample to be tested and a cathode electrode are respectively connected with a power supply and are placed in the electrolyte, and electrolytic corrosion is carried out after power is supplied;

and (5) polishing, namely cleaning and drying the sample to be tested after electrolytic corrosion.

6. The method of claim 5, wherein IN the step of preparing the anode electrode, the sample to be measured of the IN718 alloy is surface polished with sand paper and polished with diamond paste.

7. The method of claim 6, wherein the sandpaper has a particle size of 100 to 2000 mesh; and/or the diamond powder granularity in the diamond grinding paste is 1.5-3.5 mu m.

8. The method of claim 5, wherein in the step of electrolytic etching, the power source is a direct current power source and adopts an output mode of constant current output.

9. The method of claim 8, wherein the power source has an output voltage of 10V to 15V.

10. The method of claim 5, wherein in the electrolytic etching step, the electrolytic etching time is 8s to 25s.