阅读说明：本技术 一种电解抛光钛合金大尺寸棒状或板状试样的制备方法 (Preparation method of electropolished titanium alloy large-size rod-shaped or plate-shaped sample ) 是由 谭长生 潘艳 孙巧艳 肖林 于 2019-09-04 设计创作，主要内容包括：本发明一种电解抛光钛合金大尺寸棒状或板状试样的制备方法,包括：对大尺寸棒状或板状钛合金试样表面进行预处理；同时制备抛光液；将抛光液倒入电解槽中,以纯钛或钛合金材料作为阴极,预处理后的试样作为阳极,将阴极和阳极进入抛光液中；打开搅拌器对抛光液进行搅拌,接通直流稳压电源,调整参数,对试样进行电解抛光；抛光一定时间后,将试样快速移至装有酒精的烧杯内冲洗干净,吹干试样,密封保存,得到抛光的钛合金大尺寸棒状或板状试样。本发明的方法可明显增加试样抛光区域面积,提高表面EBSD信号解析率,降低表面粗糙度,且制备工艺简单,成本低廉,易于操作。(The invention relates to a preparation method of an electropolished titanium alloy large-size rod-shaped or plate-shaped sample, which comprises the following steps: pretreating the surface of a large-size rod-shaped or plate-shaped titanium alloy sample; simultaneously preparing polishing solution; pouring the polishing solution into an electrolytic bath, taking pure titanium or titanium alloy material as a cathode, taking the pretreated sample as an anode, and putting the cathode and the anode into the polishing solution; turning on a stirrer to stir the polishing solution, switching on a direct-current stabilized voltage supply, adjusting parameters, and performing electrolytic polishing on the sample; and after polishing for a certain time, quickly moving the sample into a beaker filled with alcohol, washing, drying the sample, and sealing and storing to obtain the polished titanium alloy large-size rod-shaped or plate-shaped sample. The method can obviously increase the area of a polished area of the sample, improve the EBSD signal resolution rate of the surface and reduce the surface roughness, and has the advantages of simple preparation process, low cost and easy operation.)

1. The preparation method of the large-size rod-shaped or plate-shaped sample of the electropolished titanium alloy is characterized by comprising the following steps:

step 1, pretreating the surface of a large-size rod-shaped or plate-shaped titanium alloy sample; simultaneously preparing polishing solution;

step 2, pouring the polishing solution into an electrolytic bath, taking pure titanium or titanium alloy material as a cathode, taking the pretreated sample as an anode, and putting the cathode and the anode into the polishing solution;

step 3, turning on a stirrer to stir the polishing solution, switching on a direct-current stabilized voltage supply, adjusting parameters, and performing electrolytic polishing on the sample;

and 4, polishing for a certain time, quickly moving the sample into a beaker filled with alcohol, washing, drying the sample, and sealing and storing to obtain the polished large-size rod-shaped or plate-shaped titanium alloy sample.

2. The method for preparing the large-size rod-shaped or plate-shaped sample of the electropolished titanium alloy as claimed in claim 1, wherein the step 1 of pretreating the surface of the large-size rod-shaped or plate-shaped titanium alloy sample comprises the following specific steps: firstly, grinding the surface of a large-size rod-shaped or plate-shaped titanium alloy sample by using metallographic abrasive paper to 1000 meshes; the sample was then wiped with absorbent cotton wetted with absolute ethanol and dried for use.

3. The method for preparing a large-size rod-shaped or plate-shaped sample of the electropolished titanium alloy according to claim 1, wherein the step 1 of preparing the polishing solution comprises the following specific steps: selecting 5-12% of perchloric acid and 88-95% of glacial acetic acid by volume fraction, and mixing according to the mass ratio of 3:15-17 to obtain the polishing solution.

4. The method for preparing a large-size rod-shaped or plate-shaped sample of electropolished titanium alloy as claimed in claim 1, wherein in step 2, if the pretreated sample is a large-size rod-shaped sample, the pure titanium or titanium alloy material is cylindrical; and if the pretreated sample is in a plate shape, the pure titanium or titanium alloy material is in a thin plate shape.

5. The method for preparing a large-size rod-shaped or plate-shaped sample of the electropolished titanium alloy according to claim 1, wherein the cathode in step 2 is connected with a positive electrode of a DC stabilized power supply, the anode is connected with a negative electrode of the DC stabilized power supply, and the distance between the cathode and the anode is adjusted by a pair of handheld tweezers.

6. The method for preparing a large-size rod-shaped or plate-shaped sample of electropolished titanium alloy as claimed in claim 1, wherein the voltage of the DC stabilized voltage power supply in step 3 is 40-50V, the current is 0.8-2.0A, and the working temperature is 10-30 ℃.

7. The method for preparing a large-size rod-shaped or plate-shaped sample of electropolished titanium alloy according to claim 1, wherein the polishing time in step 4 is 30-90 s.

Technical Field

The invention belongs to the technical field of structural characterization improvement of metal materials, and particularly relates to a preparation method of an electropolished titanium alloy large-size rod-shaped or plate-shaped sample.

Background

The high-strength and high-toughness titanium alloy has the characteristics of high specific strength, excellent corrosion resistance, fatigue damage resistance and the like, can meet the requirements of large-scale, high-speed and remote development of the design of an aerospace vehicle, and is widely applied to the field of aerospace. As an engineering structural member, the high-strength and high-toughness titanium alloy is inevitably subjected to complex and periodic stress action in the service process, so that the deformation damage, especially the fatigue damage of the alloy becomes a key factor for restricting the safety reliability and the long service life of the aircraft. Thereby causing the equipment and parts to be out of order or invalid, even causing serious safety accidents in serious conditions, and causing serious economic loss or casualties. Therefore, the deep research on the deformation damage mechanism of the titanium alloy is very important for providing an important theoretical basis for alloy design and structure optimization.

The In-situ SEM + EBSD In-situ stretching technology changes the traditional mode of the conventional macroscopic performance test, not only can directly observe the deformation and damage process of the material, but also can display the specific crystallographic orientation relationship, reveal more detailed problems In the material damage process and provide technical support for the organization unit deformation coordination mechanism, local strain concentration, damage formation and expansion of the high-strength and high-toughness titanium alloy consisting of the double plastic phases. However, the preparation of high quality EBSD tensile specimens is one of the challenges currently faced.

The common techniques for preparing EBSD samples today are mechanical polishing, vibratory polishing, argon ion beam polishing, and electropolishing. Mechanical polishing is because polishing paste hardness commonly used is big, and the granule is little, can the fish tail sample surface, and is unsmooth, has lost the roughness on surface to need constantly to wash by water in the polishing process, cause the oxidation easily, influenced the experimental effect. And secondly, vibration polishing and argon ion beam polishing, which can improve the quality of the EBSD sample to a certain extent, but have strict requirements on the size of the sample, generally the diameter of the sample is not more than 30mm, and the sample with larger size, such as a rod-shaped or plate-shaped sample with the length of more than 50mm, cannot be polished. The electrolytic polishing technology is a relatively common means, and different materials can be subjected to surface polishing treatment by changing the electrolytic polishing corrosive liquid. Currently, stainless steel is generally used for the cathode electrode of the titanium alloy in the electrolytic polishing process, because the stainless steel has excellent conductivity, the formation of a surface oxide film can be accelerated, but the polished area size is limited, and the EBSD sample with large size and high quality is difficult to obtain. If the cathode electrode material is changed into a pure titanium or titanium alloy material, the anode electrode connects the sample to be polished with the positive electrode of the power supply through pure titanium or titanium alloy tweezers, and compared with stainless steel, the conductivity of pure titanium or titanium alloy is poor, so that the risk of surface excessive oxidation is reduced, the area of a polishing area is increased, the electrolytic polishing of a large-size rod-shaped or plate-shaped tensile and fatigue sample can be realized at room temperature, and a high-quality surface with higher EBSD signal resolution rate is obtained.

Disclosure of Invention

The invention aims to provide a preparation method of an electropolished titanium alloy large-size rod-shaped or plate-shaped sample, which can obviously reduce the surface roughness of the titanium alloy large-size rod-shaped or plate-shaped sample.

The technical scheme adopted by the invention is that the preparation method of the large-size rod-shaped or plate-shaped sample of the electropolished titanium alloy is implemented according to the following steps:

step 1, pretreating the surface of a large-size rod-shaped or plate-shaped titanium alloy sample; simultaneously preparing polishing solution;

step 2, pouring the polishing solution into an electrolytic bath, taking pure titanium or titanium alloy material as a cathode, taking the pretreated sample as an anode, and putting the cathode and the anode into the polishing solution;

step 3, turning on a stirrer to stir the polishing solution, switching on a direct-current stabilized voltage supply, adjusting parameters, and performing electrolytic polishing on the sample;

and 4, polishing for a certain time, quickly moving the sample into a beaker filled with alcohol, washing, drying the sample, and sealing and storing to obtain the polished large-size rod-shaped or plate-shaped titanium alloy sample.

The invention is also characterized in that:

the specific process of pretreating the surface of the large-size rod-shaped or plate-shaped titanium alloy sample in the step 1 is as follows: firstly, grinding the surface of a large-size rod-shaped or plate-shaped titanium alloy sample by using metallographic abrasive paper to 1000 meshes; the sample was then wiped with absorbent cotton wetted with absolute ethanol and dried for use.

The specific process for preparing the polishing solution in the step 1 is as follows: selecting 5-12% of perchloric acid and 88-95% of glacial acetic acid by volume fraction, and mixing according to the mass ratio of 3:15-17 to obtain the polishing solution.

In the step 2, if the pretreated sample is in a large-size rod shape, the pure titanium or titanium alloy material is in a cylindrical shape; if the pretreated sample is plate-shaped, the pure titanium or titanium alloy material is thin plate-shaped.

The cathode is connected with the positive pole of the direct current stabilized power supply, the anode is connected with the negative pole of the direct current stabilized power supply, and the distance between the cathode and the anode is adjusted through the handheld tweezers.

In step 3, the voltage of the direct current stabilized power supply is 40-50V, the current is 0.8-2.0A, and the working temperature is 10-30 ℃.

And the polishing time in the step 4 is 30-90 s.

The preparation method of the large-size rod-shaped or plate-shaped sample of the electropolished titanium alloy has the beneficial effects that:

(1) the cathode electrode material is made of pure titanium or titanium alloy, so that the material is convenient to obtain, the operation is simple, the conductivity of the cathode electrode material is equivalent to that of the titanium alloy to be polished, the risk of surface multiple oxidation is reduced, and the quality and the area of electrolytic polishing are improved.

(2) The anode electrode connects the sample to be polished with the anode of the power supply through pure titanium or titanium alloy tweezers, and the distance between the sample to be polished and the cathode electrode can be controlled through the handheld tweezers, so that the polishing speed and efficiency can be regulated and controlled.

(3) The invention can polish large-size samples of the titanium alloy in a room temperature environment (10-30 ℃), does not need extra cooling measures, can reduce material loss, saves energy, improves the operability of titanium alloy electrolytic polishing and enlarges the application range of the titanium alloy electrolytic polishing.

Drawings

FIG. 1 electropolishing the shape of the cathode electrode material (cylindrical) of a bar-like tensile or fatigue specimen;

FIG. 2 is a bar-like fatigue specimen after electropolishing;

FIG. 3 electropolishing the shape of the cathode electrode material (plate) of a plate-like tensile or fatigue specimen;

FIG. 4 is a plate-like in-situ SEM tensile specimen after electropolishing;

FIG. 5 is a sample of a plate-like three-point bending notch after electropolishing;

FIG. 6 deformation characteristics of a fatigue primary crack and crack tip after cyclic loading for a certain number of cycles;

FIG. 7 micro-crack initiation characteristics of a fatigue primary crack tip region;

FIG. 8 is a structural feature diagram of an area to be subjected to an EBSD test on the surface of a rod-shaped fatigue sample;

FIG. 9 is a characteristic diagram of the IPF of example 1 along the Z direction;

FIG. 10 is a structural characteristic diagram of an area to be subjected to an EBSD test of a gauge length part of a platy in-situ SEM tensile sample;

fig. 11 IPF profile along Z-direction for example 3.

Detailed Description

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

The invention relates to a preparation method of an electropolished titanium alloy large-size rod-shaped or plate-shaped sample, which is implemented according to the following steps:

step 1, pretreating the surface of a large-size rod-shaped or plate-shaped titanium alloy sample; simultaneously preparing polishing solution;

the specific process for pretreating the surface of the large-size rod-shaped or plate-shaped titanium alloy sample comprises the following steps: firstly, grinding the surface of a large-size rod-shaped or plate-shaped titanium alloy sample by using metallographic abrasive paper to 1000 meshes; the sample was then wiped with absorbent cotton wetted with absolute ethanol and dried for use.

The specific process for preparing the polishing solution comprises the following steps: selecting 5-12% of perchloric acid and 88-95% of glacial acetic acid by volume fraction, and mixing according to the mass ratio of 3:15-17 to obtain the polishing solution.

Step 2, pouring the polishing solution into an electrolytic bath, taking pure titanium or titanium alloy material as a cathode, taking the pretreated sample as an anode, and putting the cathode and the anode into the polishing solution;

if the pretreated sample is in a large-size rod shape, the pure titanium or titanium alloy material is in a cylindrical shape; if the pretreated sample is plate-shaped, the pure titanium or titanium alloy material is thin plate-shaped.

The cathode is connected with the positive pole of the direct current stabilized power supply, the anode is connected with the negative pole of the direct current stabilized power supply, and the distance between the cathode and the anode is adjusted through the handheld tweezers.

Step 3, turning on a stirrer to stir the polishing solution, switching on a direct-current stabilized voltage supply, adjusting parameters, and performing electrolytic polishing on the sample;

the voltage of the DC stabilized power supply is 40-50V, the current is 0.8-2.0A, and the working temperature is 10-30 ℃.

And 4, after polishing for 30-90 s, quickly moving the sample into a beaker filled with alcohol, washing the sample to be clean so as to avoid residual oxide films on the surface of the sample, drying the sample, and storing the sample in a sealing manner so as to prevent pollution and oxidation to obtain the polished large-size rod-shaped or plate-shaped sample of the titanium alloy.