CN115791477A - Method for secondarily positioning residual indentation on rock surface after nano indentation test - Google Patents
Method for secondarily positioning residual indentation on rock surface after nano indentation test Download PDFInfo
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Abstract
The invention discloses a method for testing residual indentation by secondarily positioning nano indentation on a rock surface, which comprises the following steps of: s1, marking the surface of the rock after fine polishing; s2, finding a mark under an optical microscope of a nano indentation tester; s3, determining the stress influence range of the mark by means of a built-in scale ruler of the nano indentation tester; s4, carrying out nano indentation grid test near the mark, and recording the position coordinates of the indentation grid boundary relative to the mark central point; s5, performing subsequent analysis, namely positioning a mark in a visual field, and determining the position of each indentation grid; and S6, adjusting parameters of high-resolution equipment at each indentation grid position, and positioning the residual indentation marks of the nano indentation grids. The method effectively positions the nanoindentation grids by means of the pre-marking aiming at the highly heterogeneous rock surface, realizes quick, accurate and efficient secondary positioning of residual imprints on the rock surface, and facilitates more comprehensive microscopic analysis on the rock surface.
Description
Technical Field
The invention relates to the field of rock material microscopic testing, in particular to a method for secondarily positioning residual indentation on the surface of a rock after a nano indentation test.
Background
The rock is a multi-scale composite material with complex components, and the mechanical property and the fracture damage behavior thereof are key factors for controlling the stress deformation and the damage of the rock in various surface engineering and deep underground engineering, such as reservoir oil and gas exploration and development, underground coal mining, nuclear waste geological disposal engineering, underground tunnel and culvert excavation and the like. Rocks typically have a constituent structure across dimensions, with associated engineering involving dimensions that span over tens of orders of magnitude. With the development of modern physical measurement technology, microscopic measurement technology and computer image processing technology, the nanoindentation technology is gradually applied to the representation of the microscopic mechanical properties of rock materials as a means for testing the microscopic mechanical properties. The nanoindentation test can generally obtain various micromechanical parameters of the rock on a micron scale and a submicron scale, such as elastic modulus, hardness, fracture toughness, creep characteristics and the like. The in-situ micro-mechanical properties of rocks and rock minerals can be analyzed in detail by combining the nano-indentation test with a scanning electron microscope and energy dispersive X-ray spectroscopy. However, the diameter of the residual indentation left on the rock surface by the nanoindentation test is only hundreds of nanometers to a few micrometers, and the residual indentation is difficult to be positioned on the highly heterogeneous rock surface after the nanoindentation test is finished, so that great difficulty is caused in further performing a scanning electron microscope and energy dispersive X-ray spectroscopy. The field of view of high-resolution imaging techniques such as scanning electron microscopy is very limited, and the examination of submicron-level residual indentations possibly existing on the surface of a rock with a few square centimeters is a difficult task with extremely large workload, and is not beneficial to subsequent high-resolution analysis and chemical element analysis. Therefore, an effective secondary positioning method for accurately positioning the residual indentation on the rock surface is needed.
Disclosure of Invention
The invention aims to solve the problems in the prior art, and aims to provide a method for secondary positioning of residual indentation of a nano indentation test on a rock surface, which is used for accurately positioning tiny residual indentation on a highly heterogeneous rock surface, is beneficial to further carrying out surface morphology analysis, chemical element characterization and other analysis on a nano indentation area on the rock surface, and promotes deep rock micromechanical performance characterization.
In order to achieve the purpose, the invention provides the following technical scheme, and the method for secondarily positioning the residual indentation on the surface of the rock after the nano indentation test comprises the following steps:
s1, preparing a smooth and flat rock surface, detecting the roughness of the rock surface, conforming to the smoothness requirement of the tested surface of a nano indentation test, and engraving a mark in a to-be-tested area, wherein the mark center is an original point;
s2, adjusting a control panel of the nano indentation tester, and enabling a focused light beam of an optical microscope of the nano indentation tester to fall right above the mark;
s3, measuring the width of the mark by using a graduated scale of an optical microscope of the nanoindentation tester, and determining the stress influence range of the mark;
s4, searching a smooth and flat rock surface near the mark to perform nano indentation grid test, and ensuring that the indentation grid is not in a stress influence range; recording the position coordinates of the vertex of the indentation grid closest to the original point by using a graduated scale of an optical microscope of the nano indentation tester;
s5, performing subsequent analysis, namely positioning a mark in a visual field, and determining the position of each indentation grid based on the recorded coordinates;
s6, adjusting parameters of high-resolution equipment at each indentation grid position, and selecting a proper magnification factor to position the residual indentation marks of the nano indentation grids.
Further, the step S1 includes the following substeps: the rock surface is initially polished by using different grades of abrasive paper, then the shale surface is deeply polished by using diamond suspensions with different particle diameters, and then the rock surface is finely and accurately ground by ion beam milling until the roughness of the rock surface determined by an optical profiler meets the nano indentation test standard.
Further, in the step S1, the mark is preferably just visible to the naked eye.
Further, in step S1, the shape of the mark includes a cross, a circle, a square and a triangle. The adoption of different mark shapes can effectively improve the efficiency of preliminary positioning and realize quick positioning in a rough range.
Further, the step S2 includes the following substeps:
the rock sample is placed on a sample platform of a nano indentation tester, a navigation panel is adjusted on a control instrument, firstly, a focused light beam of an optical microscope is made to fall on a mark, then, the distance between a lens and the focused rock surface is adjusted, and the mark is adjusted to the center of a visual field.
Further, the step S3 includes the following substeps:
and measuring the distance between two sides of the widest part of the rock surface mark by using a graduated scale in a display window of the nanoindentation tester, recording the distance as the width of the mark, and determining the distance as a stress influence area of the mark.
Further, the step S4 includes the following sub-steps:
starting from the marking central point, searching a rock surface with a relatively smooth and flat surface and few natural pores in the visual field of an optical microscope to perform nano indentation grid test; the indentation grid border needs to keep a sufficient distance from the mark to avoid a stress concentration area caused by the mark; the shortest distance from any point on the indentation grid frame to any point on the mark is not less than the range of a stress influence area caused by the mark; and recording the mark shape and the position coordinates of the vertex of the indentation grid closest to the origin by using a graduated scale of an optical microscope of the nano indentation tester.
Further, the step S5 includes the following sub-steps:
firstly, fixing a rock sample on a sample seat according to the height specification, selecting proper parameters on an operation panel, positioning the rock sample on a sample platform to an observation point, adjusting the complete mark to be positioned at the center of a visual field, and determining the approximate position of each indentation grid in the visual field according to the shape of the mark and the coordinates of the indentation grid recorded previously.
Further, the step S6 includes the following sub-steps: and adjusting the target position to the center of the visual field, selecting a proper magnification factor, gradually adjusting the parameters of the high-resolution instrument, amplifying the target position, and positioning to a nano indentation grid area to position the residual indentation.
Compared with the prior art, the invention at least comprises the following beneficial effects:
and adding a marking step on the surface of the rock sample before the nano indentation test, and dividing the nano indentation target area through the shape of the mark. After the nano indentation test is finished, the shape of the mark and the relative coordinate position of the indentation grid are recorded, so that the residual indentation from the nano indentation test to the micron level can be quickly, efficiently and accurately positioned. The method can effectively perform secondary positioning on the nano indentation grid on the highly heterogeneous rock surface by means of pre-marking, is greatly beneficial to positioning residual indentations on the rock surface subsequently, reduces the difficulty of finding micro residual indentations on the heterogeneous rock surface, and facilitates more comprehensive microscopic analysis on the rock surface.
Drawings
FIG. 1 is a flow chart of the method of the present invention;
FIG. 2 is a schematic illustration of a rock surface marking after polishing;
FIG. 3 depicts a schematic view;
FIG. 4 is a schematic diagram of a region to be indented for nanoindentation testing;
FIG. 5 is a schematic view of a nanoindentation test;
FIG. 6 is a schematic diagram of a secondary positioning indentation matrix according to relative coordinates.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that the experimental methods described in the following embodiments are all conventional methods unless otherwise specified, and the test equipment, indenter type, and loading manner used in the nanoindentation test are not limited; the mark plays a role in auxiliary positioning, and the shape of the mark is not limited in practical application. The designation "cross" in the examples is given only for the convenience of describing the invention and does not indicate or imply that the designated mark must have a particular shape and therefore should not be construed as limiting the invention.
In the description of the present invention, it should also be noted that the term "marking" is to be understood broadly and is not limited to the means used. For example, physical damage may be formed, or chemical damage may be formed; the cutting edge can be used for scribing, and the laser scribing can also be used for scribing; the marking may be destructive or non-destructive, such as artificially creating a mark on the surface of the rock. When destructive markers such as markers are used, the extent of the stress affected zone caused by the marker is dependent on the mode of marking and the type of rock being marked. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
Examples
As shown in the figure, the invention provides a method for positioning rock surface nano-indentation test residual indentation after nano-indentation test, which comprises the following steps:
s1, performing high-precision polishing on the surface of a rock sample to be subjected to a nano indentation test to enable the surface to meet the surface roughness requirement of the nano indentation test, and making a macroscopic mark on the surface of the polished shale, wherein the center of the mark is an original point as shown in figure 2;
s2, placing the rock sample on a sample platform of a nano indentation tester, dropping a focused light beam of an optical microscope of the nano indentation tester right above the mark, adjusting the focal length of a visual field, and observing an enlarged view of a local mark, as shown in FIG. 3;
s3, determining the width of the mark from the visual field by using a graduated scale of an optical microscope of the nanoindentation tester, wherein the mark stress influence area is related to the mark width;
s4, finding a smooth and flat rock surface near the mark as an area to be indented, then dropping a nano indentation test pressure head, and carrying out nano indentation grid test, as shown in FIG. 4. After the nanoindentation test, residual indentations will be left on the rock surface, as shown in fig. 5. The distance from any point on the indentation grid frame to any point on the mark is not less than the range of the mark stress influence area; recording the position coordinates of the indentation grid boundary relative to the mark crossing center point by means of a graduated scale of an optical microscope of a nano indentation tester, as shown in fig. 4;
s5, after the nano-indentation test is finished, the position of the mark is found according to the shape of the mark when the nano-indentation residual indentation positioning is needed to be carried out on any other subsequent test, then, determining the position of the residual indentation in the visual field according to the relative coordinates of the indentation area recorded in the step S4, and taking the position as an initial target area, as shown in FIG. 6;
s6, adjusting parameters of the high-resolution equipment at the initial target area, selecting a proper magnification factor, and positioning the residual indentation marks of the nano indentation grids.
In the above embodiment, in step S1, the shape and size of the mark are determined according to the test requirements, the mark on the rock surface has a partition function, and the rock surface can be divided into different test areas, and the example illustrates a schematic diagram of the nanoindentation test of only one of the possible test areas.
In a further preferred embodiment, in step S2, the mark is easily observed under an optical microscope, and the mark can be quickly found by directly dropping the focused light beam at the indicated position right above the mark, so that the test time is saved.
In a further preferred embodiment, in step S3, the relationship between the marking width and the marking stress-affected zone should be determined individually, typically in relation to the manner of marking, the type of rock to be cut, etc., and may be determined by specific tests.
In a further preferred embodiment, in step S4, the shape of the mark and the size of the indentation grid depend on the requirements of the test, and are not limited to the examples in the figures. The calculation of the shortest distance of the indentation grid from the mark differs depending on the shape of the mark, as the case may be.
In a further preferred embodiment, in step S5, the subsequent analysis refers to any analysis relating to the area of the location of the residual indentation in the rock surface.
The above-described embodiments are merely illustrative of the preferred embodiments of the present invention and do not limit the spirit and scope of the present invention. Various modifications and improvements of the technical solutions of the present invention may be made by those skilled in the art without departing from the design concept of the present invention, and the technical contents of the present invention are all described in the claims.
Claims (9)
1. A method for secondarily positioning residual indentation on the surface of a rock after a nano indentation test is characterized by comprising the following steps:
s1, preparing a smooth and flat rock surface, detecting the roughness of the rock surface, conforming to the smoothness requirement of the tested surface of a nano indentation test, and engraving a mark in a to-be-tested area, wherein the mark center is an original point;
s2, adjusting a control panel of the nano indentation tester, and enabling a focused light beam of an optical microscope of the nano indentation tester to fall right above the mark;
s3, measuring the width of the mark by using a graduated scale of an optical microscope of the nanoindentation tester, and determining the stress influence range of the mark;
s4, searching a smooth and flat rock surface near the mark to perform nano indentation grid test, and ensuring that the indentation grid is not in a stress influence range; recording the mark shape and the position coordinate of the vertex of the indentation grid closest to the original point by using a graduated scale of an optical microscope of the nano indentation tester;
s5, performing subsequent analysis, namely positioning a mark with a corresponding shape in a visual field, and determining the position of each indentation grid based on the recorded coordinates;
and S6, adjusting parameters of high-resolution equipment at each indentation grid position, and selecting a proper magnification factor to position the residual indentation marks of the nano indentation grids.
2. The method of claim 1, wherein: the step S1 includes the following substeps: the rock surface is initially polished by using different grades of abrasive paper, then the shale surface is deeply polished by using diamond suspensions with different particle diameters, and then the rock surface is finely and accurately ground by ion beam milling until the roughness of the rock surface determined by an optical profiler meets the nano indentation test standard.
3. The method of claim 1, wherein: in the step S1, the mark is preferably a mark that is just visible to the naked eye.
4. The method of claim 3, wherein: in the step S1, the shape of the mark includes a cross shape, a circle shape, a square shape and a triangle shape.
5. The method of claim 1, wherein: the step S2 comprises the following substeps:
the rock sample is placed on a sample platform of a nano indentation tester, a navigation panel is adjusted on a control instrument, firstly, a focused light beam of an optical microscope is made to fall on a mark, then, the distance between a lens and the focused rock surface is adjusted, and the mark is adjusted to the center of a visual field.
6. The method of claim 1, wherein: the step S3 includes the following substeps:
and measuring the distance between two sides of the widest part of the rock surface mark by using a graduated scale in a display window of the nanoindentation tester, recording the distance as the width of the mark, and determining the distance as a stress influence area of the mark.
7. The method of claim 1, wherein: the step S4 includes the following substeps:
starting from the mark central point, searching a rock surface with a relatively smooth and flat surface and few natural pores in the visual field of an optical microscope to perform nano indentation grid test; the indentation grid border needs to keep a sufficient distance from the mark to avoid a stress concentration area caused by the mark; the shortest distance from any point on the indentation grid frame to any point on the mark is not less than the range of a stress influence area caused by the mark; and recording the mark shape and the position coordinates of the vertex of the indentation grid closest to the origin by using a graduated scale of an optical microscope of the nano indentation tester.
8. The method of claim 1, wherein: the step S5 includes the following substeps:
firstly, fixing the rock sample on a sample seat according to the height specification, selecting proper parameters on an operation panel, positioning the rock sample on a sample platform to an observation point, adjusting the complete mark to be positioned at the center of a visual field, and determining the approximate position of each indentation grid in the visual field according to the coordinates of the indentation grids recorded previously.
9. The method of claim 1, wherein: the step S6 includes the following substeps: and adjusting the target position to the center of the visual field, selecting a proper magnification factor, gradually adjusting the parameters of the high-resolution instrument, amplifying the target position, and positioning to a nano indentation grid area to position the residual indentation.
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| CN116678778A (en) * | 2023-08-03 | 2023-09-01 | 福建省国鼎检测技术有限公司 | Rubber wearability check out test set |
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| CN116678778A (en) * | 2023-08-03 | 2023-09-01 | 福建省国鼎检测技术有限公司 | Rubber wearability check out test set |
| CN116678778B (en) * | 2023-08-03 | 2023-10-27 | 福建省国鼎检测技术有限公司 | Rubber wearability check out test set |
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