CN109932262B - Method for measuring mechanical properties of materials at different depths - Google Patents
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Abstract
The invention belongs to the technical field of mechanical stress testing of strength characteristics of solid materials, and discloses a method for testing mechanical properties of materials at different depths by applying nanoindentation. The method comprises the following steps: (1) preparing an initial sample into a sample to be detected with an oblique section through the action of external force; (2) fixing the sample to be tested on an object which can enable the surface of the oblique section to be kept horizontal, and performing press-in test on the sample to be tested on the object by using a scanning electron microscope in-situ nanoindentor. The method ensures that the measurement error of the mechanical property of the homogeneous material is below 5 percent and the measurement error of the mechanical property of the heterogeneous material is about 10 percent. The method is simple to operate and does not need to establish a complex model.
Description
Technical Field
The invention belongs to the technical field of mechanical stress testing of strength characteristics of solid materials, and particularly relates to a method for testing mechanical properties of materials at different depths by applying a nanoindentation technology.
Background
The nano-indentation technology is a relatively common method for testing the mechanical properties of materials at a micro-scale. But the mechanical property of the material after ion irradiation is analyzed by directly utilizing a nanoindenter and a commercial clamp, so that great difficulty exists. This is mainly due to the fact that the material is irradiated by ions to generate damaged areas on the surface layer, the depth of the damaged areas is usually only a few microns, and the damage generated by monoenergetic ions and the hardening degree of the material after irradiation are also related to the depth. In addition, the mechanical properties of many heterogeneous materials, such as multilayer films and gradient materials, are also depth dependent. It is therefore necessary to analyse the mechanical properties of the material at different depths after irradiation.
However, the traditional nano indentation technology is to directly perform indentation test on the surface of a sample, mechanical property analysis of materials at different depths is realized through different indentation depth experiments, and then the mechanical property of each depth is reversely deduced according to mechanical data of different indentation depths and a model with hardness changing along with the depth, so that the method is seriously dependent on the adopted hardness-depth model and parameters, the uncertainty of a measurement result is large, and the uncertainty can reach more than 20% for a non-homogeneous material. At present, a method for analyzing the mechanical properties of materials at different depths with high accuracy and small error of test results needs to be found.
Disclosure of Invention
Objects of the invention
According to the problems in the prior art, the invention provides a method for measuring the mechanical properties of materials at different depths, which has high measurement precision and small uncertainty.
(II) technical scheme
In order to solve the problems in the prior art, the technical scheme provided by the invention is as follows:
a method of measuring mechanical properties of a material at different depths, the method comprising the steps of:
(1) preparing an initial sample with the thickness of millimeter magnitude into a sample to be detected with an oblique section through the action of external force; wherein the slope of the oblique section is determined according to the gradient of the surface mechanical property of the initial sample and the thickness of the thin area of the surface;
(2) fixing a sample to be tested on an object which can enable the surface of the oblique section to be kept horizontal, performing press-in test on the sample to be tested on the object by using a scanning electron microscope in-situ nano indenter, and vertically pressing a pressure head of the nano indenter into different positions of the oblique section; wherein the pressing depth in the hardness test is 100-400 nm; and performing a press-in experiment at a distance set to avoid mutual overlapping between press-in plastic zones; and the depth of the material corresponding to the pressing position is converted from the angle of the oblique section or is observed and measured on a scanning electron microscope.
Preferably, the step of preparing the initial sample into a sample to be measured with an oblique cross section by the external force in the step (1) comprises the following steps: fixing, grinding and polishing the initial sample by using a special fixture to prepare a sample to be detected with an oblique section;
the clamp comprises a clamp body, a sample base, a fastening screw rod, a clamp body base, an adjusting screw rod and a fixing screw rod; the sample base is in the shape of a right-angle trapezoid body with an inclined plane, and the gradient of the right-angle trapezoid body is adapted to the inclination of the inclined section; the fixture body is in a cuboid shape, a through cuboid-shaped channel is arranged at the geometric center of the fixture body, and the sample base is matched with the channel in size; a fastening screw is arranged on one side of the clamp body to fix the sample base in the horizontal direction; the fixture body base is positioned below the fixture body, and an adjusting screw rod for adjusting the height of the sample base and a fixing screw rod for fixing the fixture body base on the fixture body are arranged below the fixture body;
the preparation method of the sample to be detected comprises the following steps: fixing an initial sample on an inclined plane of a sample base, wherein one side of the initial sample is tightly attached to the higher side of the inclined plane, then placing the sample base into a cuboid cavity of a fixture body, and adjusting the height of the sample base through an adjusting screw rod, so that the position, close to the higher side of the inclined plane, of the initial sample is higher than the surface of the fixture body by 0.5-1 mm, and the other side of the initial sample is positioned in the fixture body; grinding and polishing the surface of the higher side of the initial sample, wherein the grinding thickness is based on the condition that the position of the initial sample, which is tightly attached to the higher side of the inclined plane, is flush with the surface of the clamp body;
preferably, before the initial sample is prepared into a sample with an oblique section by the action of external force in the step (1), a soft film is adhered or plated on the surface of the sample, wherein the thickness of the film is 0.5-1 mm. The soft film can well avoid the phenomenon of round edge at the junction of the oblique section and the original surface in the polishing process, and the round edge can bring the surface of the oblique section to incline, so that the indentation apparatus can not be pressed in vertically.
Preferably, the test material sample is fixed on the sample holder in the step (1) by means of adhesion.
Preferably, the sanding is performed by using sand paper, and the sanding is performed by sequentially using 600#, 800#, 1000#, 1500#, 2000#, and 3000# sand paper respectively.
Preferably, the polishing is performed in a three-step process: the first step is to sequentially adopt diamond polishing solution with the particle size of 3 mu m and diamond polishing solution with the particle size of 1 mu m for polishing; the second step is to use Al with a grain size of 0.05 μm2O3Polishing by using a polishing solution; the third step is final polishing with nano-silica to eliminate the hardened layer left by the first two polishing.
Preferably, the material of the initial sample is metal, ceramic and other inorganic materials.
Preferably, the object capable of keeping the surface of the oblique section horizontal is a sample base to ensure that the pressing head is perpendicular to the pressing surface in the pressing-in experiment, namely the oblique section.
(III) advantageous effects
By adopting the method for measuring the mechanical properties of the materials at different depths, which is provided by the invention, the oblique section is prepared on the surface of the initial sample, and the nano indenter only needs to perform press-in test on the oblique section to directly realize the measurement of the mechanical data of the samples at different depths, thereby greatly reducing the error caused by the severe dependence on the hardness-depth model and parameters adopted in the traditional method, ensuring that the measurement error of the mechanical properties of homogeneous materials is below 5 percent and the measurement error of the mechanical properties of non-homogeneous materials is about 10 percent. And the operation is simple, and a complex model is not required to be established.
In addition, compared with the traditional nano indentation test technology in which the sample is directly pressed in from the front side, the method can adopt a shallow pressing depth for pressing in the polished oblique section, the corresponding plastic zone is small, and the difference of mechanical properties in the plastic zone formed by single pressing is smaller than that in the positive pressing situation.
Drawings
FIG. 1 is an exploded view of a clamp provided by the present invention; wherein 1 is a fastening screw; 2 is a sample base; 3 is a sample to be tested; 4 is a clamp body; 5 is a fixture body base; 6 is an adjusting screw; 7 is a fixing screw;
FIG. 2 is a schematic view of an assembled clip body provided by the present invention;
FIG. 3 is a schematic diagram of the oblique cross-section indentation position and indentation of a sample.
Detailed Description
The present application will be further described with reference to the drawings and detailed description.
Example 1
(1) Preparing an initial sample with the thickness of millimeter magnitude into a sample to be detected with an oblique section through the action of external force; wherein the slope of the oblique section is determined according to the gradient of the surface mechanical property of the initial sample and the thickness of the thin area of the surface;
(2) fixing a sample to be tested on an object which can enable the surface of the oblique section to be kept horizontal, performing press-in test on the sample to be tested on the object by using a scanning electron microscope in-situ nano indenter, and vertically pressing a pressure head of the nano indenter into different positions of the oblique section; wherein the pressing depth in the hardness test is 100-400 nm; and performing a press-in experiment at a distance set to avoid mutual overlapping between press-in plastic zones; and the depth of the material corresponding to the pressing position is converted from the angle of the oblique section or is observed and measured on a scanning electron microscope.
Compared with the traditional nano indentation test technology in which the sample is directly pressed in from the front side, the method can adopt a shallow pressing depth for pressing in on a polished oblique section, the corresponding plastic zone is small, and the difference of mechanical properties in the plastic zone formed by single pressing in is smaller than that of the positive pressure situation.
Example 2
In this example, the initial sample was 304L austenitic stainless steel after heavy ion irradiation, the irradiation ions were 100MeV Ni, the peak dose was about 150dpa, and the distance from the surface was about 10 μm. After high-dose ion irradiation, a large amount of carbon deposition pollution appears on the surface of a sample, which greatly influences the conventional positive nanoindentation test result and seriously influences the interpretation of the real mechanical property of the body material. In addition, the damage generated by the irradiation of the monoenergetic ions is also depth-dependent, so that the degree of radiation hardening differs from one depth to another. Ion irradiation of the implanted particles also causes hardness differences at different depths. The mechanical data obtained when pressing in perpendicular to the surface of the sample are contributions from different depth regions within the overall plastic zone, so that the mechanical data obtained do not correspond unambiguously to different depths.
The technical scheme of the embodiment is as follows:
(1) preparing an initial sample with the thickness of millimeter magnitude into a sample to be detected with an oblique section through the action of external force; wherein the inclination of the oblique section is determined according to the gradient of the surface mechanical property of the initial sample and the thickness of the thin area of the surface layer, and the inclination is designed to be 30 degrees;
the method for preparing the sample to be detected with the oblique section by the initial sample through the external force comprises the following steps: fixing, grinding and polishing the initial sample by using a special fixture to prepare a sample to be detected with an oblique section;
the clamp comprises a clamp body 4, a sample base 2, a fastening screw rod 1, a clamp body base 5, an adjusting screw rod 6 and a fixing screw rod 7; wherein the sample base 2 is in the shape of a right-angle trapezoid with an inclined plane, and the gradient of the right-angle trapezoid corresponds to the inclination of an inclined section; the fixture body 4 is in a cuboid shape, a through cuboid-shaped channel is arranged at the geometric center of the fixture body, and the sample base 2 is adaptive to the size of the channel; a fastening screw 1 is arranged on one side of the clamp body 4 to fix the sample base 2 in the horizontal direction; the clamp body base 5 is positioned below the clamp body 4, and an adjusting screw 6 for adjusting the height of the sample base 2 and a fixing screw 7 for fixing the clamp body base 5 on the clamp body 4 are arranged below the clamp body 4;
the preparation steps of the sample to be detected are as follows: fixing an initial sample on an inclined plane of a sample base by using high-strength glue, wherein one side of the initial sample is tightly attached to the higher side of the inclined plane, then placing the sample base into a cuboid cavity of a fixture body, and adjusting the height of the sample base by using an adjusting screw rod to ensure that the position, close to the higher side of the inclined plane, of the initial sample is higher than the surface of the fixture body by 0.5-1 mm, and the other side of the initial sample is positioned in the fixture body; and (3) grinding and polishing the surface of the higher side of the initial sample, wherein the grinding thickness is based on the condition that the position of the initial sample, which is tightly attached to the higher side of the inclined plane, is flush with the surface of the clamp body.
(2) Fixing a sample to be tested on an object which can enable the surface of the oblique section to be kept horizontal, and performing press-in test on the sample to be tested on the object by using a scanning electron microscope in-situ nanoindenter, wherein the pressure head is of a Berkovich type, and the mechanical properties of the sample to be tested are hardness and elastic modulus. The maximum load of the indentation in the test was determined to be 10mN, so that the indentation depth was at most 300 nm. The indentation test was performed along the depth direction, and the minimum distance d between the indentation positions in the packing direction of the indentations was 3 μm, and the angle β between the packing direction and the intersection line of the sample surface and the oblique cross section was also 30 °. The difference in depth between two adjacent points in the close-packed direction was calculated to be d × sin (β) × sin (α) ═ 0.75 μm, so that there were at least 13 data points within a depth of 10 μm. The distance is set to avoid mutual overlapping between the pressed plastic zones; and the depth of the material corresponding to the pressing position is converted from the angle of the oblique section or is observed and measured on a scanning electron microscope. Of course, the push position can be further increased to obtain more depth data.
And after the pressing-in experiment is finished, processing the pressing-in unloading curve by using software to obtain the hardness and the elastic modulus of each pressing-in point. Measuring the distance between each indentation and the intersection line of the surface and the oblique section of the sample by adopting a scanning electron microscope, and converting to obtain the corresponding depth position
The uncertainty of the mechanical data of the 304L austenitic stainless steel after heavy ion irradiation is measured by the embodiment to be 8%.
Example 3
Different from the embodiment 2, the sanding is performed by using sand paper, and the sanding is performed by using sand paper of 600#, 800#, 1000#, 1500#, 2000#, and 3000#, respectively.
The polishing adopts a three-step method: the first step is to sequentially adopt diamond polishing solution with the particle size of 3 mu m and diamond polishing solution with the particle size of 1 mu m for polishing; the second step is to use Al with a grain size of 0.05 μm2O3Polishing by using a polishing solution; the third step is final polishing with nano-silica to eliminate the hardened layer left by the first two polishing.
Example 4
In contrast to examples 1 to 3, the starting samples were ceramic samples.
Claims (8)
1. A method for measuring mechanical properties of a material at different depths, the method comprising the steps of:
(1) preparing an initial sample with the thickness of millimeter magnitude into a sample to be detected with an oblique section through the action of external force; wherein the slope of the oblique section is determined according to the gradient of the surface mechanical property of the initial sample and the thickness of the thin area of the surface;
(2) fixing a sample to be tested on a sample seat which can enable the surface of the oblique section to be kept horizontal, and performing press-in test on the sample to be tested by using a scanning electron microscope in-situ nanoindentor, wherein a pressure head of the nanoindentor is vertically pressed into different positions of the oblique section; wherein the pressing depth in the hardness test is 100-400 nm; and performing a press-in experiment at a distance set to avoid mutual overlapping between press-in plastic zones; and the depth of the material corresponding to the pressing position is converted from the angle of the oblique section or is observed and measured on a scanning electron microscope.
2. The measuring method according to claim 1, wherein the step of preparing the initial sample into a sample to be measured having an oblique cross section by the external force in the step (1) comprises the steps of: fixing the initial sample by using a special fixture, and grinding and polishing the fixed initial sample to prepare a sample to be detected with an oblique section;
the clamp comprises a clamp body, a sample base, a fastening screw rod, a clamp body base, an adjusting screw rod and a fixing screw rod; the sample base is in the shape of a right-angle trapezoid body with an inclined plane, and the gradient of the right-angle trapezoid body is adapted to the inclination of the inclined section; the fixture body is in a cuboid shape, a through cuboid-shaped channel is arranged at the geometric center of the fixture body, and the sample base is matched with the channel in size; a fastening screw is arranged on one side of the clamp body to fix the sample base in the horizontal direction; the fixture body base is positioned below the fixture body, and an adjusting screw rod for adjusting the height of the sample base and a fixing screw rod for fixing the fixture body base on the fixture body are arranged below the fixture body;
the preparation method of the sample to be detected comprises the following steps: fixing an initial sample on an inclined plane of a sample base, wherein one side of the initial sample is tightly attached to the higher side of the inclined plane, then placing the sample base into a cuboid cavity of a fixture body, and adjusting the height of the sample base through an adjusting screw rod, so that the position, close to the higher side of the inclined plane, of the initial sample is higher than the surface of the fixture body by 0.5-1 mm, and the other side of the initial sample is positioned in the fixture body; and (3) grinding and polishing the surface of the higher side of the initial sample, wherein the grinding thickness is based on the condition that the position of the initial sample, which is tightly attached to the higher side of the inclined plane, is flush with the surface of the clamp body.
3. The measuring method according to claim 1, wherein a soft film is adhered or plated on the surface of the initial sample before the initial sample is prepared into a sample having an oblique cross section by the external force in the step (1), wherein the film has a thickness of 0.5 to 1 mm.
4. The measuring method according to claim 1, wherein the sample to be measured is fixed on the sample holder in step (1) by means of adhesion.
5. The measuring method according to claim 2, wherein the sanding in step (2) is performed by using sandpaper, and the sanding is performed by using sandpaper of 600#, 800#, 1000#, 1500#, 2000#, and 3000#, respectively.
6. The measuring method according to claim 2, wherein the polishing in the step (2) is performed by a three-step method: the first step is to sequentially adopt diamond polishing solution with the particle size of 3 mu m and diamond polishing solution with the particle size of 1 mu m for polishing; the second step is to use Al with a grain size of 0.05 μm2O3Polishing by using a polishing solution; the third step is final polishing with nano-silica.
7. The method according to claim 1, wherein the material of the initial sample in step (1) is metal, ceramic or other inorganic material.
8. The measuring method according to claim 1, wherein the sample holder capable of keeping the surface of the oblique cross section horizontal in the step (2) is a sample base.
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201653804U (en) * | 2010-04-09 | 2010-11-24 | 北京工业大学 | Nano-indentation system based on scanning electron microscope |
| CN102494997A (en) * | 2011-11-18 | 2012-06-13 | 江苏大学 | Detection method for interface bonding strength of particle reinforced metal matrix composite material |
| RU2475719C1 (en) * | 2011-07-08 | 2013-02-20 | Аскар Джамилевич Мингажев | Evaluation method of strengthening degree of surface layer of solid materials |
| CN104330298A (en) * | 2014-10-30 | 2015-02-04 | 北京理工大学 | Method and device for evaluating and measuring mesomechanics/micromechanics performance of surface gradient metal material |
| CN107831085A (en) * | 2017-11-02 | 2018-03-23 | 吉林大学 | A kind of method of hardness of the test metal material in different compression distances |
| CN109540663A (en) * | 2018-10-18 | 2019-03-29 | 吉林大学 | Modification method of the concora crush head verticality to impression test mechanical parameters |
-
2019
- 2019-04-12 CN CN201910293782.5A patent/CN109932262B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201653804U (en) * | 2010-04-09 | 2010-11-24 | 北京工业大学 | Nano-indentation system based on scanning electron microscope |
| RU2475719C1 (en) * | 2011-07-08 | 2013-02-20 | Аскар Джамилевич Мингажев | Evaluation method of strengthening degree of surface layer of solid materials |
| CN102494997A (en) * | 2011-11-18 | 2012-06-13 | 江苏大学 | Detection method for interface bonding strength of particle reinforced metal matrix composite material |
| CN104330298A (en) * | 2014-10-30 | 2015-02-04 | 北京理工大学 | Method and device for evaluating and measuring mesomechanics/micromechanics performance of surface gradient metal material |
| CN107831085A (en) * | 2017-11-02 | 2018-03-23 | 吉林大学 | A kind of method of hardness of the test metal material in different compression distances |
| CN109540663A (en) * | 2018-10-18 | 2019-03-29 | 吉林大学 | Modification method of the concora crush head verticality to impression test mechanical parameters |
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