阅读说明：本技术 一种基于TiAl单晶EBSD样品的电解抛光液及其电解方法 (TiAl single crystal EBSD sample-based electrolytic polishing solution and electrolytic method thereof ) 是由 陈�光 陈奉锐 祁志祥 逯帆 侯锐 肖随 许昊 于 2020-05-21 设计创作，主要内容包括：本发明公开一种基于TiAl单晶EBSD样品的电解抛光液及其电解方法,属于TiAl合金表面处理技术领域。该电解抛光液由如下体积比的组分组成,高氯酸：丙三醇：无水乙醇=(12～15):(8～11):(100～104),电解方法为：将经过打磨处理的EBSD试样粗抛、细抛,超声清洗后作为阳极,不锈钢片为阴极,电解抛光液为电解液,进行电解。本发明的电解抛光方法,能有效去除TiAl单晶表面的应力层及氧化层,电解抛光后TiAl单晶表面平整且光亮清洁、无连续腐蚀坑,该方法具有工艺步骤简单易于操作,抛光液绿色环保,且效果稳定、样品标定率高等优点。(The invention discloses an electrolytic polishing solution based on a TiAl single crystal EBSD sample and an electrolytic method thereof, belonging to the technical field of TiAl alloy surface treatment. The electrolytic polishing solution comprises the following components in volume ratio: glycerol: absolute ethyl alcohol (12-15) = (8-11): 100-104), the electrolysis method is: and roughly polishing and finely polishing the polished EBSD sample, performing ultrasonic cleaning, and then performing electrolysis by using the polished EBSD sample as an anode, a stainless steel sheet as a cathode and an electrolytic polishing solution as an electrolyte. The electrolytic polishing method can effectively remove the stress layer and the oxide layer on the surface of the TiAl monocrystal, and the surface of the TiAl monocrystal after electrolytic polishing is flat, bright and clean and free of continuous corrosion pits.)

1. An electrolytic polishing solution based on a TiAl single crystal EBSD sample is characterized by comprising the following components in volume ratio: glycerol: absolute ethyl alcohol (12-15) = (8-11): 100-104).

2. An electrolysis method based on a TiAl single crystal EBSD sample is characterized by comprising the following steps:

(1) firstly, roughly polishing an EBSD sample subjected to polishing treatment on flannelette, finely polishing the EBSD sample on synthetic fiber polishing cloth, and ultrasonically cleaning the EBSD sample for 10min by using absolute ethyl alcohol;

(2) electrolyzing by using a stainless steel sheet as a cathode, the sample obtained in the step (1) as an anode and the electrolytic polishing solution as the electrolyte according to claim 1, wherein the polishing time is set to be 60-120s, the electrolytic voltage is 20-26V, the distance between the anode and the cathode is 80mm, and the polishing temperature is-30-15 DEG C⁰C。

3. The method according to claim 2, wherein in the step (1), the polishing liquid used for the rough polishing and the fine polishing is OP-S silica suspension with a particle size of 0.6 μm.

4. The method of claim 2, wherein the electrolysis process is stirred using an electromagnetic stirrer.

5. The method of claim 2, wherein the voltage-current curve is recorded during the electrolysis, and the inflection point of the curve at the critical potential and the end point of the potential are taken as straight lines, which intersect with the abscissa of the voltage-current curve, and the resulting intersection point is the theoretical decomposition voltage, i.e., the electrolysis voltage.

Technical Field

The invention relates to an electrolytic polishing solution based on a TiAl single crystal EBSD sample and an electrolytic method thereof, belonging to the field of surface treatment of TiAl alloy materials.

Background

The Electron backscattering Diffraction (EBSD) technique is a method for determining the crystal structure, orientation and related information based on the analysis of a Diffraction chrysanthemic zone formed by exciting an Electron beam on the surface of an inclined sample in a scanning Electron microscope. EBSD requires that the sample surface not have a residual mechanical polishing-induced processing strain layer, but also be smooth, free of an oxide film, and free of continuous etch pits, so that electropolishing is commonly used as the last processing step for preparing EBSD samples.

TiAl alloy is the only light heat-resistant structural material which can be used for a long time in an oxidation environment at the temperature of more than 600 ℃ at present, and the theoretical density is only 3.9 g/cm³And the Ni-based superalloy is about 8.5 g/cm³The TiAl single crystal invented by Nanjing university of science and technology overcomes the two problems of large room temperature brittleness and low service temperature of the TiAl alloy, realizes excellent combination of strength, plasticity and creep resistance and cross-over promotion of comprehensive performance, and has great application prospect (ZL ZL201410529844.5, ZL 201410528019.3). the TiAl single crystal removes crystal boundary, and the casting structure is a full-lamellar structure, wherein α₂-Ti₃The Al phase is a hard phase, the gamma-TiAl phase is a soft phase, the corrosion resistance of the Al phase and the gamma-TiAl phase to the polishing solution is greatly different, and continuous corrosion pits can be generated on the surface by adopting the conventional electrolytic polishing solution, so that the calibration rate of a sample is low. In addition, the conventional electrolytic polishing solution adopts chemical solvents which are volatile, strong in irritation and toxic to human bodies, such as methanol, n-butanol, glacial acetic acid, hydrofluoric acid, ethers and the like as the polishing solution. Based on the reasons, the development of the electrolytic polishing solution and the electrolytic method thereof which have the advantages of low toxicity, no irritation, environmental protection, good stability of the polishing process and high calibration rate is urgently needed.

Disclosure of Invention

The invention aims to provide an electrolytic polishing solution for an EBSD sample based on TiAl single crystal and an electrolytic method thereof.

The technical solution for realizing the purpose of the invention is as follows: an electrolytic polishing solution based on a TiAl single crystal EBSD sample, which consists of the following components in volume ratio: glycerol: absolute ethyl alcohol (12-15) = (8-11): 100-104).

An electrolysis method based on a TiAl single crystal EBSD sample comprises the following steps:

(1) firstly, roughly polishing an EBSD sample subjected to polishing treatment on flannelette, finely polishing the EBSD sample on synthetic fiber polishing cloth, and ultrasonically cleaning the EBSD sample for 10min by using absolute ethyl alcohol;

(2) electrolyzing by taking a stainless steel sheet as a cathode, the sample obtained in the step (1) as an anode and an electrolytic polishing solution as electrolyte, wherein during electrolysis, the polishing time is set to be 60-120s, the electrolytic voltage is 20-26V, the distance between the anode and the cathode is 80mm, and the polishing temperature is-30-15 DEG C⁰C。

Preferably, in the step (1), the polishing solution used for rough polishing and fine polishing is OP-S silicon oxide suspension with the grain size of 0.6 μm.

Preferably, the electrolysis process is stirred using an electromagnetic stirrer.

Compared with the prior art, the invention has the following beneficial effects:

(1) the invention relates to an electrolytic polishing method of TiAl single crystal materials, which belongs to the first time.

(2) According to the method, the theoretical decomposition voltage of electrolytic polishing is obtained by obtaining the electrolytic characteristic curve, the electrolytic polishing efficiency is improved, the stability of the obtained electrolytic polishing process is good, the EBSD pattern calibration rate is high, and the detection precision is greatly improved.

(3) The electrolytic polishing solution has low cost, is easy to prepare and store and is harmless to human bodies.

(4) The polishing process has the advantages of simple equipment, easy operation, convenient material acquisition of cathode materials and simple preparation.

Drawings

FIG. 1 is a graph showing the electropolishing characteristics in example 1 of the present invention.

FIG. 2 is a SEM scanning surface topography of a TiAl single crystal EBSD sample in example 1 of the invention.

FIG. 3 is a graph showing the electropolishing characteristics in example 2 of the present invention.

FIG. 4 is a SEM scanning surface topography of a TiAl single crystal EBSD sample in example 2 of the invention.

FIG. 5 is a relative contrast chart of EBSD analysis of TiAl single crystal in example 2 of the present invention.

FIG. 6 is a graph showing the electropolishing characteristics of example 3.

FIG. 7 is an SEM scanning surface topography of a TiAl single crystal EBSD sample in example 3 of the invention.

FIG. 8 is an SEM scanning surface topography of a TiAl single crystal EBSD sample in comparative example 1 of the invention.

FIG. 9 is a relative contrast chart of EBSD analysis of TiAl single crystal in comparative example 1 of the present invention.

Detailed Description

The invention is further elucidated with reference to the embodiments and the drawings. The scope of the invention is not limited to the disclosure.

In the method for electrolyzing the TiAl-single-crystal-based EBSD sample of the present invention described with reference to fig. 3, 5, and 8, the electrolytic voltage set at the time of electrolysis was 20 to 26V, which is a value obtained by recording a voltage-current change curve during electrolysis, and making a straight line intersecting the abscissa of the voltage-current change curve with the inflection points (points a1, C1, E1), i.e., current jump points and end points (points a2, C2, E2) of the curve at the critical potential, thereby obtaining an electropolishing characteristic curve, wherein the intersection point (I = 0) is the theoretical decomposition voltage of electropolishing (point B, D, F), i.e., the optimum electrolytic voltage.