CN116519416A - Sample preparation method for industrial pure titanium metallographic structure observation - Google Patents
Sample preparation method for industrial pure titanium metallographic structure observation Download PDFInfo
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- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 title claims abstract description 84
- 239000010936 titanium Substances 0.000 title claims abstract description 84
- 229910052719 titanium Inorganic materials 0.000 title claims abstract description 83
- 238000005464 sample preparation method Methods 0.000 title claims abstract description 12
- 238000005498 polishing Methods 0.000 claims abstract description 74
- 239000000126 substance Substances 0.000 claims abstract description 38
- 238000000034 method Methods 0.000 claims abstract description 35
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 32
- 238000005520 cutting process Methods 0.000 claims abstract description 24
- 238000002360 preparation method Methods 0.000 claims abstract description 21
- 239000003518 caustics Substances 0.000 claims abstract description 11
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims abstract description 9
- 239000013078 crystal Substances 0.000 claims abstract description 9
- 238000001035 drying Methods 0.000 claims abstract description 9
- 238000004140 cleaning Methods 0.000 claims abstract description 5
- 238000012545 processing Methods 0.000 claims abstract description 5
- 238000005422 blasting Methods 0.000 claims abstract description 4
- 238000010008 shearing Methods 0.000 claims abstract description 4
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 claims description 148
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 56
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 54
- 239000000203 mixture Substances 0.000 claims description 34
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims description 32
- 229910017604 nitric acid Inorganic materials 0.000 claims description 32
- PEDCQBHIVMGVHV-UHFFFAOYSA-N Glycerine Chemical compound OCC(O)CO PEDCQBHIVMGVHV-UHFFFAOYSA-N 0.000 claims description 30
- 238000005260 corrosion Methods 0.000 claims description 24
- 230000007797 corrosion Effects 0.000 claims description 24
- 239000008367 deionised water Substances 0.000 claims description 21
- 229910021641 deionized water Inorganic materials 0.000 claims description 21
- 239000003153 chemical reaction reagent Substances 0.000 claims description 17
- 230000000694 effects Effects 0.000 claims description 14
- 238000003756 stirring Methods 0.000 claims description 14
- 239000000463 material Substances 0.000 claims description 13
- 238000009835 boiling Methods 0.000 claims description 6
- 239000007788 liquid Substances 0.000 claims description 6
- 230000008569 process Effects 0.000 claims description 5
- 239000000243 solution Substances 0.000 claims description 5
- 239000007864 aqueous solution Substances 0.000 claims description 4
- 230000010287 polarization Effects 0.000 claims description 2
- CMDGQTVYVAKDNA-UHFFFAOYSA-N propane-1,2,3-triol;hydrate Chemical compound O.OCC(O)CO CMDGQTVYVAKDNA-UHFFFAOYSA-N 0.000 claims description 2
- 244000137852 Petrea volubilis Species 0.000 abstract description 21
- 238000004519 manufacturing process Methods 0.000 abstract description 4
- 238000010438 heat treatment Methods 0.000 abstract description 3
- 238000000227 grinding Methods 0.000 description 37
- 230000000052 comparative effect Effects 0.000 description 11
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 9
- 238000011010 flushing procedure Methods 0.000 description 7
- 229920000742 Cotton Polymers 0.000 description 6
- 229910001069 Ti alloy Inorganic materials 0.000 description 6
- 239000004576 sand Substances 0.000 description 6
- 238000005406 washing Methods 0.000 description 6
- 238000005516 engineering process Methods 0.000 description 5
- 230000008901 benefit Effects 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 239000012535 impurity Substances 0.000 description 4
- 230000008859 change Effects 0.000 description 3
- 238000005088 metallography Methods 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 239000002994 raw material Substances 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 239000003086 colorant Substances 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 239000007769 metal material Substances 0.000 description 2
- 238000007781 pre-processing Methods 0.000 description 2
- 239000013535 sea water Substances 0.000 description 2
- MGWGWNFMUOTEHG-UHFFFAOYSA-N 4-(3,5-dimethylphenyl)-1,3-thiazol-2-amine Chemical compound CC1=CC(C)=CC(C=2N=C(N)SC=2)=C1 MGWGWNFMUOTEHG-UHFFFAOYSA-N 0.000 description 1
- 235000015842 Hesperis Nutrition 0.000 description 1
- 235000012633 Iberis amara Nutrition 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000010612 desalination reaction Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 239000007943 implant Substances 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 150000007522 mineralic acids Chemical class 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- JCXJVPUVTGWSNB-UHFFFAOYSA-N nitrogen dioxide Inorganic materials O=[N]=O JCXJVPUVTGWSNB-UHFFFAOYSA-N 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 238000007517 polishing process Methods 0.000 description 1
- 230000008092 positive effect Effects 0.000 description 1
- 238000004080 punching Methods 0.000 description 1
- 210000000323 shoulder joint Anatomy 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- FZUJWWOKDIGOKH-UHFFFAOYSA-N sulfuric acid hydrochloride Chemical compound Cl.OS(O)(=O)=O FZUJWWOKDIGOKH-UHFFFAOYSA-N 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
- G01N1/2806—Means for preparing replicas of specimens, e.g. for microscopal analysis
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
- G01N1/286—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q involving mechanical work, e.g. chopping, disintegrating, compacting, homogenising
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
- G01N1/32—Polishing; Etching
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/84—Systems specially adapted for particular applications
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- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating And Analyzing Materials By Characteristic Methods (AREA)
- Sampling And Sample Adjustment (AREA)
Abstract
The invention discloses a sample preparation method for industrial pure titanium metallographic structure observation, which comprises the steps of performing linear cutting on a sample, and removing processing hardening layers such as shot blasting, shearing and the like; sequentially polishing the linear cutting surface by using a plurality of sand papers, and placing the linear cutting surface in a chemical polishing agent after polishing; placing the polished sample in a metallographic corrosive, cleaning the corroded sample with absolute ethyl alcohol, and then drying with cold air; and (5) placing the treated sample under a metallographic microscope for observation. The method can well obtain the industrial pure titanium metallographic structure, adopts a unique chemical polishing agent and a metallographic corrosive agent to ensure that the grain boundary is clear, and solves the problems of unclear grain boundary, twin crystals, scratches, low sample preparation efficiency and the like of the industrial pure titanium metallographic structure caused by the limitation of a sample preparation method in the prior art; the clear display of industrial pure titanium grains with different specifications and different heat treatment systems can be realized; the metallographic structure display method is simple, convenient and quick to operate, can accurately grade the grain size, and has important significance for the production of industrial pure titanium.
Description
Technical Field
The invention belongs to the technical field of metallographic structure display of metal materials, and particularly relates to a sample preparation method for industrial pure titanium metallographic structure observation.
Background
Titanium and titanium alloy have many advantages such as low density, high specific strength, high temperature resistance, good corrosion resistance and biocompatibility, etc., and can be widely applied in various fields such as aerospace, metallurgical chemical industry, automobiles and ships, biomedicine, etc. Industrial pure titanium can be used for manufacturing corrosion-resistant valves, pipelines, heat exchangers, condensers, sea water desalination system structural members and the like in marine ships and petrochemical industry due to the excellent corrosion resistance; because of the characteristics of high specific strength and light weight, the material can be used for manufacturing artificial satellites, rockets, jet engine components, landing gear, fasteners and the like on the aviation and aerospace, and is also one of the preferred materials for light weight of automobiles. In addition, industrial pure titanium has a great deal of applications in biomedical and daily life, such as human implants, shoulder joints, splints, golf heads, tennis rackets, etc. Industrial pure titanium is ubiquitous in the industry and civil industry, the development speed is rapid, and the application technology is mature and perfect. However, the industrial pure titanium has a great limit to the deep application in various fields due to the defects of low strength, poor comprehensive mechanical properties and the like. Therefore, the strength and the comprehensive mechanical property of the industrial pure titanium are improved, and the method becomes one of the hot problems of domestic and foreign scholars.
Industrial pure titanium is classified according to the content of impurity elements. It has excellent punching technological performance and welding performance, is insensitive to heat treatment and tissue type, and has certain strength under satisfactory plastic condition, and its strength is mainly dependent on the content of interstitial element oxygen and nitrogen. It has high corrosion resistance in sea water, but poor in inorganic acid, and is suitable for work at-253-350 deg.c. Nowadays, with the continuous progress of industrial technologies in the fields of aviation, aerospace, weapons, ships and the like, correspondingly, the use requirements on the light weight, high performance and long service life of metal materials are also higher and higher, and the performances of metals such as steel, aluminum, magnesium and the like and alloys thereof are gradually unable to meet the actual demands in the fields.
In order to study the basic properties of commercially pure titanium for better application, it is necessary to observe the microstructure of commercially pure titanium; the quantitative metallography principle is adopted, and the three-dimensional space morphology, the tissue type and the uniformity degree of the alloy tissue and the quantitative relation between the tissue and the performance are determined by measuring and calculating the metallography microstructure of the grinding surface of the two-dimensional metallography sample, so that a test basis is provided for improving the performance of the titanium alloy.
The brand of industrial pure titanium material is TA1, TA2, TA3 and TA4, belongs to alpha-type titanium alloy, and has the advantages of good comprehensive mechanical properties, such as high specific strength, low heat conductivity and the like; because the alpha-phase crystal grain size in the industrial pure titanium plate is smaller, the grain boundary angle difference is large, the grain boundary corrosion degree difference is large easily in the corrosion process, and some grain boundaries are over-corroded and cannot be displayed, so that the error is large in the grading of the grain size and even the grading cannot be performed, and a clear equiaxial structure is difficult to obtain by adopting a conventional corrosive agent and a structure display method.
Therefore, how to prepare a metallographic structure corrosive agent so as to effectively present the metallographic structure of the industrial pure titanium plate and accurately measure the grain size and grain size of the metallographic structure corrosive agent is a technical problem which needs to be solved by the person skilled in the art at present.
Disclosure of Invention
In order to solve the detection problem that the metallurgical structure of the titanium alloy is difficult to display, the invention provides a sample preparation method for observing the metallurgical structure of the industrial pure titanium, and the method can obtain the clear equiaxial structure of the industrial pure titanium, has clear grain boundaries and obvious contrast ratio among grains under the polarizing condition, and solves the problems of inaccurate grain size measurement and the like caused by the fuzzy grain boundaries.
In order to achieve the above object, the present invention provides a sample preparation method for industrial pure titanium metallographic structure observation, the method comprising the steps of:
(1) and (3) selecting an industrial pure titanium plate sample for linear cutting, cutting into specification sheets, and removing a hardening layer generated by shot blasting and shearing processing of the sheet sample.
The section specification of the industrial pure titanium plate sample after the wire cutting in the step (1) is 10mm in length and width and 2-10mm in thickness.
(2) Polishing the linear cutting surface, sequentially using 200# abrasive paper, 600# abrasive paper, 1000# abrasive paper and 1200# abrasive paper, and rotating the sample by 90 degrees every time when the abrasive paper is replaced, and polishing until the polishing trace of the last step completely disappears;
mechanically grinding the sheet-shaped industrial pure titanium plate sample, sequentially grinding the metallographic structure observation plane of the industrial pure titanium plate sample step by adopting metallographic water sand paper of No. 200, no. 600, no. 1000 and No. 1200, rotating the grinding direction by 90 degrees after each water sand paper change so as to ensure that the trace of the last grinding is eliminated, and flushing sand grains after the grinding is finished.
(3) Mechanically polishing the polished sample in the step (2) to obtain a polished surface, polishing the polished surface in a chemical polishing agent, taking out the polished surface after the liquid surface starts boiling for 5 seconds, and putting the polished surface into a re-polishing device for 0.5 seconds at intervals of 1 second;
the chemical polishing agent in the step (3) consists of hydrofluoric acid: nitric acid: sulfuric acid is formed by the volume ratio of 10:12:5; the composition of the chemical polishing agent is hydrofluoric acid, nitric acid and sulfuric acid which are all analytically pure reagents; the preparation process is as follows: at room temperature, 10ml of hydrofluoric acid is put into a plastic container, 12ml of nitric acid is added into the hydrofluoric acid for stirring, and 5ml of sulfuric acid is slowly added into the container for continuous stirring until the mixture is uniform.
(4) Placing the polished sample in the step (3) into a metallographic corrosive agent for corrosion, wiping the corroded sample with absorbent cotton for 2-4 times, taking out, and immediately flushing with clear water and large water flow; then washing with absolute ethyl alcohol, and drying with cold air;
the metallographic etchant in the step (4) is prepared from hydrofluoric acid: deionized water is formed according to the volume ratio of 1:10; the composition hydrofluoric acid is an analytically pure reagent; the preparation process is as follows: at room temperature, 2ml of hydrofluoric acid is put into a plastic container, and then 20ml of deionized water is added into the hydrofluoric acid, and the mixture is continuously stirred until the mixture is uniformly mixed.
The metallographic etchant in the step (4) is prepared from hydrofluoric acid: deionized water: glycerol is formed according to the volume ratio of 1:5:5; the composition hydrofluoric acid and glycerol are all analytically pure reagents; the preparation process is as follows: adding 10ml of glycerol into a beaker at room temperature, slowly adding 10ml of deionized water into the glycerol, and continuously stirring until the mixture is uniform to obtain a glycerol aqueous solution with the volume fraction of 50%; then 2ml of hydrofluoric acid is taken and added into 20ml of glycerol water solution with the volume fraction of 50 percent, and the mixture is continuously stirred until the mixture is uniformly mixed; and obtaining the metallographic corrosive.
(5) And (3) placing the sample treated in the step (4) under a metallographic microscope, and observing a metallographic structure.
Observing the metallographic structure in the step (5), and selecting one of normal light and polarized light from a light path under a microscope; preferably, the observation is performed by means of polarization and differential interference phase contrast.
The specific process of observing the metallographic structure in the step (5) is as follows: inserting a polarizer, an analyzer, a field diaphragm and a differential interference piece DIC assembly of a microscope into a light path, adjusting a fine tuning knob on the DIC assembly to enable the angle between incident light and a reflector to reach 90 degrees, selecting a filter to enable each crystal grain of an image of a differential interference phase contrast to show different color effects, and then observing industrial pure titanium metallographic structures. Through adjusting the fine tuning knob on the DIC component, the interference colors in the view field tend to be consistent, and a proper background interference color is selected, so that the differential interference phase contrast image achieves the best effect, namely, different phases show different relief effects.
Compared with the prior art, the invention has the beneficial effects that:
(1) the industrial pure titanium has softer texture, and is extremely easy to generate twin crystals and scratches in the processing process, the sand paper grinding process and the mechanical polishing process, so the invention adopts the modes of linear cutting, multi-mesh sand paper grinding and chemical polishing to eliminate the twin crystals and the scratches.
(2) The invention can realize the clear display of industrial pure titanium grains with different specifications and different heat treatment systems.
(3) The method is simple, convenient and quick to operate, can accurately grade the grain size, and has important significance for the production of industrial pure titanium.
Drawings
FIG. 1 is a microscopic structure diagram of a TA2 industrial pure titanium plate sample of example 1 with a thickness of 4.0mm, which is magnified 500 times after chemical polishing and corrosion by hydrofluoric acid aqueous solution;
FIG. 2 is a microscopic structure diagram of a TA2 industrial pure titanium plate sample of comparative example 1 having a thickness of 4.0mm at 500 x magnification obtained by conventional mechanical polishing without chemical polishing;
FIG. 3 is a 500-fold magnification microscopic structure of a TA2 industrial pure titanium plate sample of comparative example 2 having a thickness of 4.0mm, which has been subjected to chemical polishing and corrosion by the recommended corrosive agent of GB/T5168-2020;
FIG. 4 is a graph showing the microstructure of a TA2 industrial pure titanium plate sample of example 2 having a thickness of 4.0mm, which has been chemically polished and etched with aqueous hydrofluoric acid, and then magnified 500 times under polarized light and differential interference conditions;
FIG. 5 is a microscopic structure diagram of a TA2 industrial pure titanium plate sample of example 3 with a thickness of 1.5mm, which is magnified 500 times after chemical polishing and corrosion by hydrofluoric acid aqueous solution;
FIG. 6 is a microscopic structure diagram of a TA1 industrial pure titanium plate sample of example 4 with a thickness of 4.0mm, which is magnified 500 times after chemical polishing and corrosion with aqueous hydrofluoric acid.
Detailed Description
The invention is further illustrated below in connection with specific examples, but is not limited in any way. For the sake of brevity, the reagents used in the examples below are commercially available products unless otherwise specified, and the methods used are conventional methods unless otherwise specified. The microscope used in the examples was an Olympus-BX41M metallographic microscope.
Example 1
A sample preparation method for industrial pure titanium metallographic structure observation, comprising the following steps:
(1) and (3) selecting an industrial pure titanium TA2 plate sample for linear cutting, cutting into sheets with the specification, the length and the width of 10mm and the thickness of 4mm, and removing a hardening layer generated by shot blasting and shearing processing of the sheet sample.
(2) And (3) mechanically grinding the linear cutting surface, sequentially using 200# abrasive paper, 600# abrasive paper, 1000# abrasive paper and 1200# abrasive paper, rotating the sample by 90 degrees every time when the abrasive paper is replaced, and grinding until the last grinding trace completely disappears.
(3) And (3) mechanically polishing the polished sample in the step (2) to obtain a polished surface, polishing the polished surface in a chemical polishing agent, taking out the polished surface after the liquid surface starts boiling for 5 seconds, and putting the polished surface in the chemical polishing agent for re-polishing for 0.5 seconds at intervals of 1 second.
The chemical polishing agent consists of hydrofluoric acid: nitric acid: sulfuric acid is formed by the volume ratio of 10:12:5; the composition of the chemical polishing agent is hydrofluoric acid, nitric acid and sulfuric acid which are all analytically pure reagents; the preparation process is as follows: at room temperature, 10ml of hydrofluoric acid is put into a plastic container, 12ml of nitric acid is added into the hydrofluoric acid for stirring, and 5ml of sulfuric acid is slowly added into the container for continuous stirring until the sulfuric acid and the nitric acid are completely dissolved with each other.
(4) Placing the polished sample in the step (3) into a metallographic corrosive agent for corrosion, wiping the corroded sample with absorbent cotton for 2-4 times, taking out, and immediately flushing with clear water and large water flow; and then washing with absolute ethyl alcohol, and drying with cold air.
The metallographic corrosive is prepared from hydrofluoric acid: deionized water is formed according to the volume ratio of 1:10; the composition hydrofluoric acid is an analytically pure reagent; the preparation process is as follows: at room temperature, 2ml of hydrofluoric acid is put into a plastic container, and then 20ml of deionized water is added into the hydrofluoric acid, and the mixture is continuously stirred until the mixture is uniformly mixed.
(5) And (3) placing the sample treated in the step (4) under a metallographic microscope, observing a metallographic structure, wherein a light path is normal light.
The metallographic structure obtained by the method of example 1 is shown in fig. 1, and the chemical polishing method does not produce surface scratches and impurities, so that the microstructure is bright and clean, the nitric acid proportion in the polishing agent is slightly more than that of hydrofluoric acid, the equiaxed grain boundaries are not excessively corroded, and the purpose of adding sulfuric acid is to protect the grain boundaries, because the corrosiveness of the polishing agent is converged due to the viscous property of sulfuric acid; the solution is boiled under the action of nitric acid, and when pure titanium is put into the polishing agent, nitrogen dioxide gas generated by chemical reaction is generated to enable the solution to be boiled, so that the whole corrosion speed is accelerated, the surface of a sample is enabled to achieve the purpose of brightness in a short time, the effect is far better than the mechanical polishing effect, and the preparation is made for the subsequent corrosion; the corrosive provided by the invention only uses hydrofluoric acid and water, and nitric acid is not added, so that the purpose of the nitric acid is that although the nitric acid can lighten the surface, the crystal boundary can be desalted, so that the invention breaks through the conventional method, and the corrosive provided by the invention only uses hydrofluoric acid to add water, thereby having good effect, clear crystal boundary, uniform corrosion and great benefit on the accuracy of grading the grain size.
Comparative example 1
The metallurgical structure display method of industrial pure titanium plate comprises the following specific steps:
step 1, selecting an industrial pure titanium TA2 plate, and then cutting the plate into slices with certain specification by using wire cutting;
step 2, preprocessing the flaky industrial pure titanium sheet material so as to observe metallographic structure of the flaky industrial pure titanium sheet material;
and 3, mechanically polishing and corroding the grinding surface.
And 4, observing under a microscope, wherein the light path is normal light.
In the step 1, the slice specification of the sheet-shaped industrial pure titanium sheet material with certain specification is that the length and the width are 10mm, and the thickness is 4mm.
In the step 2, the pretreatment of the flaky industrial pure titanium sheet material is specifically as follows: firstly, mechanically grinding a flaky industrial pure titanium sheet, sequentially adopting metallographic water sand paper of No. 200, no. 600, no. 1000 and No. 1200 to grind a metallographic structure observation plane of the industrial pure titanium sheet step by step, rotating the grinding direction by 90 degrees after each water sand paper replacement so as to ensure that the trace of the last grinding is eliminated, and washing off sand grains after finishing grinding; then wiping with absorbent cotton for 2-4 times, taking out, immediately flushing with clear water and large water flow, then cleaning with absolute ethyl alcohol, and finally drying with a blower and cold air for standby.
In the step 3, the mechanically polished canvas is used as the material until the mirror surface is polished.
The corrosive for displaying industrial pure titanium metallographic structure comprises the following raw material components: hydrofluoric acid and deionized water, wherein the hydrofluoric acid is an analytically pure reagent. The specific preparation process is as follows: a certain amount of deionized water was added to hydrofluoric acid at room temperature and stirred until completely miscible. The corrosive comprises 1 part of hydrofluoric acid and 10 parts of deionized water according to volume fractions.
The metallographic structure obtained by the method of comparative example 1, as shown in FIG. 2, is characterized in that the conventional mechanical polishing is used, the efficiency is low and the grinding marks are difficult to remove, because pure titanium is soft, and the polishing agent easily adheres to the surface so that it is difficult to polish to have no pits and scratches.
Comparative example 2
The metallurgical structure display method of industrial pure titanium plate comprises the following specific steps:
step 1, selecting an industrial pure titanium TA2 plate, and then cutting the plate into slices with certain specification by using wire cutting;
step 2, preprocessing the flaky industrial pure titanium sheet material so as to observe metallographic structure of the flaky industrial pure titanium sheet material;
and 3, chemically polishing and corroding the grinding surface.
And 4, observing under a microscope, wherein the light path is normal light.
In the step 1, the slice specification of the sheet-shaped industrial pure titanium sheet material with certain specification is that the length and the width are 10mm, and the thickness is 4mm.
In the step 2, the pretreatment of the flaky industrial pure titanium sheet material is specifically as follows: firstly, mechanically grinding a flaky industrial pure titanium sheet, sequentially adopting metallographic water sand paper of No. 200, no. 600, no. 1000 and No. 1200 to grind a metallographic structure observation plane of the industrial pure titanium sheet step by step, rotating the grinding direction by 90 degrees after each water sand paper replacement so as to ensure that the trace of the last grinding is eliminated, and washing off sand grains after finishing grinding; then wiping with absorbent cotton for 2-4 times, taking out, immediately flushing with clear water and large water flow, then cleaning with absolute ethyl alcohol, and finally drying with a blower and cold air for standby.
In the step 3, the chemical polishing agent for displaying industrial pure titanium metallographic structure comprises the following raw material components: hydrofluoric acid, nitric acid, sulfuric acid. The specific preparation process is as follows: at room temperature, a certain amount of hydrofluoric acid, nitric acid, sulfuric acid are mixed and stirred until completely miscible. In the chemical polishing agent, hydrofluoric acid, nitric acid and sulfuric acid are respectively 10 parts by volume of hydrofluoric acid, 12 parts by volume of nitric acid and 5 parts by volume of sulfuric acid.
The corrosive for displaying the metallurgical structure of the industrial pure titanium is the recommended corrosive (No. 6 corrosive) in the second table of GB/T5168-2020 titanium and titanium alloy high-low power structure inspection method, and comprises the following raw material components: hydrofluoric acid, hydrochloric acid,Deionized water. The specific preparation proportion is as follows: 20ml HCl+40ml HF+40ml H 2 O。
The hydrofluoric acid, the nitric acid and the sulfuric acid hydrochloric acid are all analytically pure reagents.
As shown in FIG. 3, the metallographic structure obtained by the method of comparative example 2 has the advantages that the crystal boundary becomes fuzzy due to the existence of hydrochloric acid in the corrosive, the concentrations of hydrochloric acid and hydrofluoric acid are too high, the proportion of deionized water is low, the corrosion speed of the corrosive is too high, and the corrosion time is not easy to grasp.
Example 2
A sample preparation method for industrial pure titanium metallographic structure observation, comprising the following steps:
(1) and (3) selecting an industrial pure titanium TA2 plate sample for linear cutting, wherein the industrial pure titanium TA2 plate sample is cut into specification sheets, the length and the width are 10mm, and the thickness is 4mm.
(2) Mechanically grinding the linear cutting surface, sequentially using 200# metallographic water sand paper, 600# metallographic water sand paper, 1000# metallographic water sand paper and 1200# metallographic water sand paper, rotating the grinding direction by 90 degrees every time when the sand paper is replaced, and grinding until the last grinding trace completely disappears; after finishing the grinding, sand grains are washed away.
(3) And (3) mechanically polishing the polished sample in the step (2) to obtain a polished surface, polishing the polished surface in a chemical polishing agent, taking out the polished surface after the liquid surface starts boiling for 5 seconds, and putting the polished surface into the chemical polishing agent for re-polishing for 0.5 seconds at intervals of 1 second.
The chemical polishing agent consists of hydrofluoric acid: nitric acid: sulfuric acid is formed by the volume ratio of 10:12:5; the composition of the chemical polishing agent is hydrofluoric acid, nitric acid and sulfuric acid which are all analytically pure reagents; the preparation process is as follows: at room temperature, 10ml of hydrofluoric acid is put into a plastic container, 12ml of nitric acid is added into the hydrofluoric acid for stirring, and 5ml of sulfuric acid is slowly added into the container for continuous stirring until the sulfuric acid and the nitric acid are completely dissolved with each other.
(4) And (3) placing the polished sample in the step (3) into a metallographic corrosive agent for corrosion, cleaning the corroded sample with absolute ethyl alcohol, and then drying by cold air.
The metallographic corrosive is prepared from hydrofluoric acid: deionized water is formed according to the volume ratio of 1:10; the composition hydrofluoric acid is an analytically pure reagent; the preparation process is as follows: at room temperature, 2ml of hydrofluoric acid is put into a plastic container, and then 20ml of deionized water is added into the hydrofluoric acid, and the mixture is continuously stirred until the mixture is uniformly mixed.
(5) And (3) placing the sample treated in the step (4) under a metallographic microscope, observing a metallographic structure, wherein a light path is polarized light.
The prepared metallographic sample is placed on a microscope, a polarizer and an analyzer are inserted into a light path, the polarizer and the analyzer are in an orthogonal state, a field diaphragm and a differential interference piece DIC assembly are sequentially inserted, interference colors in a field tend to be consistent through adjusting a fine tuning knob, a proper background interference color is selected, an image of a differential interference phase contrast achieves an optimal effect, and a metallographic structure of an industrial pure titanium sheet sample can be clearly seen.
The metallographic structure obtained by the method of example 2 is shown in fig. 4, and pure titanium grains have relief effect, grain boundary sag and bright light trim under polarized light condition and RGB color mode, which is beneficial to distinguishing each grain, and has positive effect on grain size rating as in example 1.
Example 3
A sample preparation method for industrial pure titanium metallographic structure observation, comprising the following steps:
(1) and (3) selecting an industrial pure titanium TA2 plate sample for linear cutting, wherein the industrial pure titanium TA2 plate sample is cut into specification sheets, the length and the width are 10mm, and the thickness is 1.5mm.
(2) Mechanically grinding the linear cutting surface, sequentially grinding the metallographic observation plane of the industrial pure titanium plate step by using 200#, 600#, 1000#, 1200# metallographic water sand paper, and rotating the grinding direction by 90 degrees after each water sand paper change so as to ensure that the trace of the last grinding is eliminated; after finishing the grinding, sand grains are washed away.
(3) And (3) mechanically polishing the polished sample in the step (2) to obtain a polished surface, polishing the polished surface in a chemical polishing agent, taking out the polished surface after the liquid surface starts boiling for 5 seconds, and putting the polished surface in the chemical polishing agent for re-polishing for 0.5 seconds at intervals of 1 second.
The chemical polishing agent consists of hydrofluoric acid: nitric acid: sulfuric acid is formed by the volume ratio of 10:12:5; the composition of the chemical polishing agent is hydrofluoric acid, nitric acid and sulfuric acid which are all analytically pure reagents; the preparation process is as follows: at room temperature, 10ml of hydrofluoric acid is put into a plastic container, 12ml of nitric acid is added into the hydrofluoric acid for stirring, and 5ml of sulfuric acid is slowly added into the container for continuous stirring until the sulfuric acid and the nitric acid are completely dissolved with each other.
(4) Placing the polished sample in the step (3) into a metallographic corrosive agent for corrosion, wiping the corroded sample with absorbent cotton for 2-4 times, taking out, and immediately flushing with clear water and large water flow; and then washing with absolute ethyl alcohol, and drying with cold air.
The metallographic corrosive is prepared from hydrofluoric acid: deionized water is formed according to the volume ratio of 1:10; the composition hydrofluoric acid is an analytically pure reagent; the preparation process is as follows: at room temperature, 2ml of hydrofluoric acid is put into a plastic container, and then 20ml of deionized water is added into the hydrofluoric acid, and the mixture is continuously stirred until the mixture is uniformly mixed.
(5) And (3) placing the sample treated in the step (4) under a metallographic microscope, observing a metallographic structure, wherein a light path is polarized light.
The metallographic structure obtained by the method of example 3 is shown in fig. 5, the metallographic sample is an annealed sheet with the thickness of 1.5mm, at the thickness, impurity atoms obtain higher energy to be concentrated at the grain boundary due to large deformation, and the grain size is far smaller than that of a large-specification sheet, so that the sample preparation and corrosion difficulty are more difficult than that of a thick plate, but the effect is not inferior to that of a thick plate from a metallographic photograph, and therefore, the method is applicable to pure titanium sheets with different specifications such as a thin sheet, a thick plate and the like.
Example 4
A sample preparation method for industrial pure titanium metallographic structure observation, comprising the following steps:
(1) and (3) selecting an industrial pure titanium TA1 plate sample for linear cutting, wherein the industrial pure titanium TA1 plate sample is cut into specification sheets, the length and the width are 10mm, and the thickness is 4.0mm.
(2) Mechanically grinding the linear cutting surface of the sheet-shaped industrial pure titanium plate, sequentially grinding the metallographic observation plane of the industrial pure titanium plate step by using 200# metallographic water sand paper, 600# metallographic water sand paper, 1000# metallographic water sand paper and 1200# metallographic water sand paper, and rotating the grinding direction by 90 degrees after each water sand paper change so as to ensure that the trace of the last grinding is eliminated; after finishing the grinding, sand grains are washed away.
(3) And (3) mechanically polishing the polished sample in the step (2) to obtain a polished surface, polishing the polished surface in a chemical polishing agent, taking out the polished surface after the liquid surface starts boiling for 5 seconds, and putting the polished surface into the chemical polishing agent for re-polishing for 0.5 seconds at intervals of 1 second.
The chemical polishing agent consists of hydrofluoric acid: nitric acid: sulfuric acid is formed by the volume ratio of 10:12:5; the composition of the chemical polishing agent is hydrofluoric acid, nitric acid and sulfuric acid which are all analytically pure reagents; the preparation process is as follows: at room temperature, 10ml of hydrofluoric acid is put into a plastic container, 12ml of nitric acid is added into the hydrofluoric acid for stirring, and 5ml of sulfuric acid is slowly added into the container for continuous stirring until the sulfuric acid and the nitric acid are completely dissolved with each other.
(4) Placing the polished sample in the step (3) into a metallographic corrosive agent for corrosion, wiping the corroded sample with absorbent cotton for 2-4 times, taking out, and immediately flushing with clear water and large water flow; and then washing with absolute ethyl alcohol, and drying with cold air.
The metallographic corrosive is prepared from hydrofluoric acid: deionized water is formed according to the volume ratio of 1:10; the composition hydrofluoric acid is an analytically pure reagent; the preparation process is as follows: at room temperature, 2ml of hydrofluoric acid is put into a plastic container, and then 20ml of deionized water is added into the hydrofluoric acid, and the mixture is continuously stirred until the mixture is uniformly mixed.
(5) And (3) placing the sample treated in the step (4) under a metallographic microscope, observing a metallographic structure, wherein a light path is normal light.
The metallographic structure obtained by the method of example 4 is shown in fig. 6, the brand of the sample is industrial pure titanium TA1, and it can be seen that the metallographic photograph obtained by the method has clear grain boundaries and no artifacts such as impurities, scratches and the like affecting the rating.
In summary, it can be seen from examples 1-4 and comparative examples 1-2, in combination with the accompanying figures 1-6:
comparative example 1 differs from example 1 in that in the polishing step, example 1 uses the chemical polishing agent and polishing method of the present invention, and comparative example 1 uses the conventional mechanical (canvas) polishing method, and it is apparent that the chemical polishing effect of the present invention is good and the efficiency is high.
Comparative example 2 is different from example 1 in that the metallographic etchant formulated is different; wherein, the comparative example 2 has the components of hydrochloric acid, the proportion of hydrofluoric acid and water is too large, and the corrosion effect is poor; it can be seen that the combination of hydrofluoric acid and water is more suitable for etching pure titanium.
Example 2 is different from example 1 in that the observation mode of example 2 adopts polarized light, the previous sample preparation corrosion method is completely consistent, the final effect is better, and when the output is a color metallographic photograph or a color report is sent out, the polarized light color photograph is more visual.
Example 3 and example 4 are different from example 1 in the specifications and grades of the industrial pure titanium sheet, but there is no difference in the final effect, and it can be seen that the method is applicable to all the specifications and grades of industrial pure titanium.
Many possible variations and modifications of the disclosed technology can be made by anyone skilled in the art without departing from the scope of the technology, or the technology can be modified to be equivalent. Therefore, any simple modification, equivalent variation and modification of the above embodiments according to the technical substance of the present invention shall still fall within the scope of the technical solution of the present invention.
Claims (7)
1. A sample preparation method for industrial pure titanium metallographic structure observation, which is characterized by comprising the following steps:
(1) selecting an industrial pure titanium plate sample, performing linear cutting, cutting into specification slices, and removing a hardening layer generated by shot blasting and shearing processing of the slice sample;
(2) polishing the linear cutting surface, sequentially using 200# abrasive paper, 600# abrasive paper, 1000# abrasive paper and 1200# abrasive paper, and rotating the sample by 90 degrees every time when the abrasive paper is replaced, and polishing until the polishing trace of the last step completely disappears;
(3) mechanically polishing the polished sample in the step (2) to obtain a polished surface, polishing the polished surface in a chemical polishing agent, taking out the polished surface after the liquid surface starts boiling for 5 seconds, and putting the polished surface in the chemical polishing agent for re-polishing for 0.5 seconds at intervals of 1 second;
(4) placing the polished sample in the step (3) into a metallographic corrosive agent for corrosion, cleaning the corroded sample with absolute ethyl alcohol, and then drying by cold air;
(5) and (3) placing the sample treated in the step (4) under a metallographic microscope, and observing a metallographic structure.
2. The method according to claim 1, wherein the wire-cut industrial pure titanium sheet material sample in the step (1) has a slice size of 10mm in length and 10mm in width and a thickness of 2-10mm.
3. The method of claim 2, wherein the chemical polishing agent of step (3) is comprised of hydrofluoric acid: nitric acid: sulfuric acid is formed by the volume ratio of 10:12:5; the composition of the chemical polishing agent is hydrofluoric acid, nitric acid and sulfuric acid which are all analytically pure reagents; the preparation process is as follows: at room temperature, 10ml of hydrofluoric acid is put into a plastic container, 12ml of nitric acid is added into the hydrofluoric acid for stirring, and 5ml of sulfuric acid is slowly added into the container for continuous stirring until the mixture is uniform.
4. A method according to claim 3, wherein the metallographic etchant of step (4) consists of hydrofluoric acid: deionized water is formed according to the volume ratio of 1:10; the composition hydrofluoric acid is an analytically pure reagent; the preparation process is as follows: at room temperature, 2ml of hydrofluoric acid is put into a plastic container, and then 20ml of deionized water is added into the hydrofluoric acid, and the mixture is continuously stirred until the mixture is uniformly mixed.
5. The method of claim 4, wherein the metallographic etchant of step (4) consists of hydrofluoric acid: deionized water: glycerol is formed according to the volume ratio of 1:5:5; the composition hydrofluoric acid and glycerol are all analytically pure reagents; the preparation process is as follows: adding 10ml of glycerol into a beaker at room temperature, slowly adding 10ml of deionized water into the glycerol, and continuously stirring until the mixture is uniform to obtain a glycerol aqueous solution with the volume fraction of 50%; then 2ml of hydrofluoric acid is taken and added into 20ml of glycerol water solution with the volume fraction of 50 percent, and the mixture is continuously stirred until the mixture is uniformly mixed; and obtaining the metallographic corrosive.
6. The method of claim 5, wherein the observing metallographic structure of step (5) is performed under a microscope, and the light path is selected from one of normal light and polarized light; preferably, the observation is performed by means of polarization and differential interference phase contrast.
7. The method according to claim 6, wherein the specific process of observing metallographic structure in step (5) is: inserting a polarizer, an analyzer, a field diaphragm and a differential interference piece DIC assembly of a microscope into a light path, adjusting a fine tuning knob on the DIC assembly to enable the angle between incident light and the reflector to reach 90 degrees, selecting a filter to enable each crystal grain of an image of a differential interference phase contrast to present different color effects, and then observing the metallographic structure of an industrial pure titanium sample.
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| CN117907055A (en) * | 2024-01-17 | 2024-04-19 | 东北大学 | Preparation method of metallographic specimen of rare earth dysprosium |
| CN117969356A (en) * | 2024-04-01 | 2024-05-03 | 陕西天成航空材料股份有限公司 | Detection method and detection device for average grain size of titanium alloy |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN117907055A (en) * | 2024-01-17 | 2024-04-19 | 东北大学 | Preparation method of metallographic specimen of rare earth dysprosium |
| CN117969356A (en) * | 2024-04-01 | 2024-05-03 | 陕西天成航空材料股份有限公司 | Detection method and detection device for average grain size of titanium alloy |
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