CN114839039A - Metal matrix composite fiber ejection test device and test method - Google Patents
Metal matrix composite fiber ejection test device and test method Download PDFInfo
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- CN114839039A CN114839039A CN202210353128.0A CN202210353128A CN114839039A CN 114839039 A CN114839039 A CN 114839039A CN 202210353128 A CN202210353128 A CN 202210353128A CN 114839039 A CN114839039 A CN 114839039A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/24—Investigating strength properties of solid materials by application of mechanical stress by applying steady shearing forces
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/40—Investigating hardness or rebound hardness
- G01N3/42—Investigating hardness or rebound hardness by performing impressions under a steady load by indentors, e.g. sphere, pyramid
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Abstract
The invention belongs to the technical field of micro-nano mechanical tests, and relates to a metal matrix composite fiber ejection test device and a test method. The testing device comprises symmetrical clamping jaws, a cylindrical sample placing platform, a manual adjusting ring, a corner adjusting base and a fixing base. The device and the test method provided by the invention are suitable for fiber ejection and push-in tests of metal-based composite material samples with fibers of different diameters and cross-sectional shapes, the test samples can be repeatedly and nondestructively installed and disassembled for multiple times, the pollution of gluing and fixing on the samples and sample tables and mechanical damage caused in the sample disassembly process are avoided, the samples can be repeatedly used and can be subsequently used for analyzing a subsequent microstructure, meanwhile, the clamping jaws are clamped perpendicular to the plane of the samples, the shearing force caused by fixing the samples is avoided, and a solid foundation is provided for accurately measuring the interface shearing strength, the interface friction force and the interface bonding force of the metal-based composite material.
Description
Technical Field
The invention belongs to the technical field of micro-nano mechanical tests, and relates to a metal matrix composite fiber ejection test device and a test method.
Background
The continuous fiber reinforced metal matrix composite material is formed by compounding high-strength, high-modulus and low-density fibers serving as a reinforcement with a corresponding metal matrix. The composite material has the advantages of light weight, high specific strength and specific stiffness, excellent high temperature resistance, fatigue resistance and corrosion resistance, and wide application prospect in the fields of aviation, aerospace, automobiles, electronics and the like. The interface is the unique important component of the composite material, the fiber/matrix interface plays a key role in the performance of the composite material, and the interface shear strength is an important parameter for measuring the performance of the fiber/matrix interface. At present, the methods for testing the interfacial shear strength of the composite material mainly comprise: fiber drawing, microdroplet debonding, single fiber breaking, fiber ejection, etc. Because of differences in sample preparation, testing technology, microscopic model simplification and the like, interface shear strength values obtained by different testing methods have certain differences. How to eliminate the interference factors in the test method and make the obtained result closer to the real interface shear strength is an important problem to be solved urgently in the research of the interface strength of the continuous fiber reinforced metal matrix composite.
Both the fiber drawing method and the microdroplet debonding method are suitable for resin-based composite materials, the preparation technology of test samples for the fiber drawing test of metal-based composite materials is complex, and the test measurement result is influenced by factors such as the fiber embedding length, the fiber exposed length measurement accuracy and the like, so that the dispersibility is high; and the microdroplet debonding test requires that the matrix is transparent and is not suitable for the metal matrix composite material. When the fiber ejection test is carried out by the nanoindentor, a sample can be intercepted from the actual composite material, the in-situ test can be carried out on the actual metal matrix composite material, and compared with other methods, the obtained result is closer to the shear strength of the actual interface. The conventional nanoindentor is not provided with a special fiber ejection test platform, and the conventional nanoindentor generally adopts the method that one or a plurality of rectangular grooves with the width far smaller than the diameter of a sample and the length longer than the diameter of the sample are arranged on the surface of the platform, the sample is fixed on the platform, the fiber position corresponding to the groove area is determined, and then a diamond flat pressure head is used for pushing out the fiber. The prior art adopts a nanoindentor to perform fiber ejection test, and has the following problems: (1) sample holding means can cause contamination of the sample or introduce additional radial forces at the fiber and matrix interface. The common method is that liquid glue or paraffin is used for pasting a test piece on a platform groove, a sample tested by the metal-based composite material is usually a round sheet-shaped sample with the diameter of about 5mm, and the fiber at the part corresponding to the groove is easily stained with the glue in the fixing process, so that the sample pollution is caused, and the accuracy of the test result is influenced; meanwhile, when the sample is mechanically taken down by using tweezers or a blade and the like, the sample is damaged and has glue residues, residual colloid cannot be thoroughly removed even if the sample is soaked and separated by using acetone, so that the sample is scrapped, and the microstructure of a test area cannot be further analyzed. And through the fixing method that the clamping blocks are arranged on the periphery of the sample and radial force is applied to prop against the sample, for the fiber reinforced composite material, the shearing force applied to all fibers and matrix interfaces in the sample is increased, and the test data is wrong. (2) The test area is small, and the fiber ejection test can not be synchronously carried out at the original position when the region of interest is observed and determined. Aiming at the groove platform, the test range of the sample is limited in the area corresponding to the width of the groove, the test on any interested position in the sample cannot be realized, and the number of fibers which can be tested in the range of the groove is limited due to the small size of the test piece. (3) And the free positioning test of the surface of the sample cannot be realized. The test platform does not have a rotation function, and the manual placement platform is inevitable to have errors with a system coordinate system, so that the fiber cannot be accurately positioned by using a sample reference coordinate system.
The invention provides a metal matrix composite fiber ejection test device and a test method for nanoindentation, which effectively solve the problems encountered in continuous fiber reinforced metal matrix composite fiber ejection tests, are very convenient to assemble and disassemble during testing, can be repeatedly used for testing, and greatly improve the accuracy and efficiency of testing.
Disclosure of Invention
The invention provides a metal matrix composite fiber ejection test device and a test method for nanoindentation, which are used for fixing a sample during a fiber ejection test, solve the problems of sample pollution, sample damage, introduction of additional stress, small test sample amount and incapability of accurate positioning caused by the fixing method, and ensure the accuracy and flexibility of the test.
The purpose of the invention is realized by the following technical scheme:
a metal matrix composite fiber ejection test device for nanoindentation comprises symmetrical clamping jaws 1, a cylindrical sample placing platform 2, a manual adjusting ring 3, a corner adjusting base 4 and a fixed base 5; a circular groove 8 is formed in the center of the end face of the cylindrical sample placing platform 2, the symmetrical clamping jaws 1 are installed in through grooves symmetrically formed in the cylindrical sample placing platform 2, the clamping ends of the symmetrical clamping jaws 1 are approximately trapezoidal bodies, the outer sides of the two clamping ends are rounded rectangles, the inner sides of the two clamping ends are circular arcs concentric with the groove 8, the radius of the circular arc at the bottom of the clamping end close to the platform 2 is equal to that of the groove 8, the plane where the upper circular arc is located is parallel to the bottom face, and the side bottom angle of the circular arc of each trapezoidal body is 45 degrees; the cylindrical sample placing platform 2 is connected with a bolt fastener 21 through a step 19 and a step 20 on the corner adjusting base 4; a magnet 16 is arranged at the center of the fixed base 5 and connected through a wedge-shaped bolt fastener 17, and the corner adjusting base 4 is connected with the magnetic force applied through a step 18 on the fixed base 5; the manual adjusting ring 3 is in threaded connection with the cylindrical sample placing platform 2, a reverse groove 15 is formed in the lower portion of the manual adjusting ring 3, the circular ring piece 14 is clamped in the groove, and the symmetrical clamping claws 1 are fixedly connected with the circular ring piece 14 through springs 13; a long pin 12 is arranged in the middle of the spring, and the length of the pin is consistent with that of the spring in a relaxed state;
The circular groove 8 is positioned in the center of the cylindrical sample placing platform 2, and the diameter of the groove is 2-5 mm.
Under the clamping state, the height of the symmetrical clamping claws 1 higher than the cylindrical sample placing platform 2 is 0.5 mm-1.5 mm.
The fixed base 5 and the corner adjusting base 4 are made of martensitic stainless steel in ferromagnetic materials, and the symmetrical clamping jaws 1, the cylindrical sample placing platform 2 and the manual adjusting ring 3 are made of austenitic stainless steel.
The surface of the cylindrical sample placing platform 2 is respectively provided with an identification line 6 which is convenient for centering a round sample and an identification line 7 which is convenient for centering a square sample in cross section, and a vertical cross-shaped scribing line 22 which is used for unifying a sample coordinate system and a test system coordinate system.
The surface of the manual adjusting ring 3 is provided with anti-skid threads; the corner adjusting base 4 is provided with corner scribed lines 9 with the intervals of 1 degree ranging from 0 degree to 360 degrees; four fixing bolt holes 11 which are uniformly distributed are arranged on the fixing base 5, and a marking line 10 with a rotation angle of 0 degree is carved along the diameter direction of the base.
The testing method of the metal matrix composite fiber ejection testing device comprises the following steps:
1) preparing a sample with two parallel end surfaces, the end surfaces vertical to the length direction of the fiber and the thickness of 0.1-0.7 mm;
2) selecting a high-load module of a nanoindenter, and installing a conical flat pressing head;
3) Carrying out air compression calibration on the indentation shaft;
4) calibrating the relative position of the needle point and the optical lens: installing an aluminum sample on a nano indenter test platform, pressing a single or a group of indentations on the aluminum sample, finding the indentations under a nano indenter optical lens, checking whether the center of an X, Y-axis cross marking line at the central position of the optical lens field coincides with the set indentation position, and if the center deviates, adjusting to completely coincide;
5) placing the sample on a sample placing platform, and unifying X, Y axes of the sample and a coordinate system of a test device platform by using a centering identification line for the sample with a regular shape; placing the area where the fibers to be subjected to the ejection test are located above the circular groove 8, and rotating the manual adjusting ring 3 clockwise to enable the two clamping jaws 1 to move downwards to clamp the edge of the sample and fix the sample to be tested;
6) adsorbing or fixing a fixing base 5 of the testing device on a nano-indenter testing platform by adopting a bolt;
7) focusing the surface of a sample on an optical lens observation interface of the nanoindentor, setting a working area boundary, and setting a test range capable of performing an ejection test, namely a nanoindentor working area, according to the position of a clamping jaw;
8) observing the overall appearance of a sample in a working area at a light mirror observation interface, selecting fibers needing to be subjected to ejection test testing, and coinciding the center of the cross section of the target fiber with the center of a X, Y-axis cross identification line at the center position of a light mirror view field of a nano indenter by adjusting the X, Y axis of a nano indenter testing platform and the rotation angle of a corner adjusting base;
9) Under the indentation module of the nanoindentor, a displacement control mode is selected, a loading function is trapezoidal loading, and a loading curve comprises: setting maximum displacement, loading time and unloading time, starting the test, simultaneously setting a plurality of fiber ejection positions, and recording coordinates;
10) after the test is finished, starting from the set first position, obtaining a force-displacement curve by using an analysis module of nanoindenter software, and obtaining information such as the length of the ejected fiber and the deformation amount of a matrix near the fiber by using the in-situ imaging function of the nanoindenter;
11) the hand adjusting ring 3 is rotated counterclockwise to move the two claws 1 upward, and the sample is removed from the cylindrical sample placement platform 2 by tweezers and loaded into a sample cell.
The conical flat pressure head used in the step 2) has a plane diameter of 50 μm; the load of the high-load module is 100 mN-30N.
And the air compression calibration of the indentation shaft in the step 3) is carried out before the test after each sample replacement.
The test sample is a fiber reinforced metal matrix composite, the test sample is one of round, oval, square, rectangular or irregular sheet-shaped forms, the test plane is the cross section of the composite test sample vertical to the length direction of the fiber, the thickness of the test sample is 0.1-0.5 mm, and the diameter of the fiber is 50-150 μm. Compared with the prior art.
The invention has the beneficial effects that:
1. the invention provides a metal matrix composite fiber ejection test device and a test method for a nanoindenter, wherein a clamping jaw and a hand-adjusting ring clamping structure are utilized, a test sample can be repeatedly and nondestructively installed and disassembled for multiple times, the pollution of gluing and fixing on the sample and a sample table and mechanical damage caused in the sample disassembly process are avoided, the sample can be repeatedly utilized and can be subsequently used for subsequent microstructure structural analysis, the working efficiency is greatly improved, and meanwhile, the clamping jaw is clamped in a vertical sample plane, and the shearing force introduced by sample fixing is avoided.
2. The manual adjusting ring clamping structure is internally composed of a spring, a long pin, a ring piece and a reverse groove, all parts are connected with one another and mutually influenced, the overall harmony of the clamping jaws when fixing a sample is ensured, and the problem of local overload deformation of the sample caused by installation and disassembly is avoided.
3. The relative position of the clamping jaw and the circular groove is adopted to determine a test area capable of carrying out a fiber ejection test in the sample, and the ejection test can be carried out by randomly selecting an interested position while observing different fiber characteristics of the section to be tested in the test in a larger range.
4. The surface of the platform is provided with a centering identification line, and for round and rectangular samples, the identification line and a vertical cross-shaped scribed line on a test screen of a nano indenter can be directly utilized to unify a sample coordinate system and a test system coordinate system; for any shape sample, the rotation angle adjusting base is rotated to drive the sample placing platform to rotate, so that the rotation motion of the sample is realized, and the unification of a sample coordinate system and a nanoindentation testing system coordinate system is achieved. The test of multidirectional and arbitrary designated positions on the surface of the sample can be realized.
5. The clamp and the test method provided by the invention are suitable for the ejection and push-in tests of the fibers of different diameters and the fibers of the metal matrix composite sample with the cross-sectional shape, and provide a solid foundation for accurately measuring the interface shear strength, the interface friction force and the interface bonding force of the metal matrix composite.
Drawings
FIG. 1 is a side view of a fiber ejection test apparatus;
FIG. 2 is an oblique view of a fiber ejection test apparatus;
FIG. 3 is a cross-sectional view taken along line A-A of FIG. 1;
fig. 4 is a front view and a cross-sectional view in the direction B-B of one jaw of the symmetrical jaw 1.
Detailed Description
The invention is further described with reference to the following figures and examples.
As shown in fig. 1-4, a metal matrix composite fiber ejection test device for nanoindentation comprises symmetrical clamping jaws 1, a cylindrical sample placement platform 2, a manual adjusting ring 3, a corner adjusting base 4 and a fixed base 5; a circular groove 8 is formed in the center of the end face of the cylindrical sample placing platform 2, and the diameter of the groove is 2-5 mm; the symmetrical clamping jaws 1 are arranged in through grooves symmetrically arranged on the cylindrical sample placing platform 2, the clamping ends of the symmetrical clamping jaws 1 are approximately trapezoidal bodies, the outer sides of the two clamping ends are rounded rectangles, the inner sides of the two clamping ends are circular arcs concentric with the groove 8, the radius of a circular arc at the bottom of the clamping end close to the platform 2 is equal to that of the groove 8, the plane where the upper circular arc is located is parallel to the bottom surface, and the bottom angle of the circular arc side of each trapezoidal body is 45 degrees; the cylindrical sample placing platform 2 is connected with a bolt fastener 21 through a step 19 and a step 20 on the corner adjusting base 4; a magnet 16 is arranged at the center of the fixed base 5 and connected through a wedge-shaped bolt fastener 17, and the corner adjusting base 4 is connected with the magnetic force applied through a step 18 on the fixed base 5; the manual adjusting ring 3 is in threaded connection with the cylindrical sample placing platform 2, a reverse groove 15 is formed in the lower portion of the manual adjusting ring 3, the circular ring piece 14 is clamped in the groove, and the symmetrical clamping claws 1 are fixedly connected with the circular ring piece 14 through springs 13; a long pin 12 is arranged in the middle of the spring, and the length of the pin is consistent with that of the spring in a relaxed state;
And under the clamping state of the symmetrical clamping jaws 1, the heights of the symmetrical clamping jaws 1 higher than the cylindrical sample placing platform 2 are 0.5-1.5 mm.
The fixed base 5 and the corner adjusting base 4 are made of martensitic stainless steel in ferromagnetic materials, and the symmetrical clamping jaws 1, the cylindrical sample placing platform 2 and the manual adjusting ring 3 are made of austenitic stainless steel.
The surface of the cylindrical sample placing platform 2 is respectively provided with an identification line 6 which is convenient for centering a round sample and an identification line 7 which is convenient for centering a square sample in cross section, and a vertical cross-shaped scribing line 22 which is used for unifying a sample coordinate system and a test system coordinate system.
The surface of the manual adjusting ring 3 is provided with anti-skid threads; the corner adjusting base 4 is provided with corner scribed lines 9 with the intervals of 1 degree ranging from 0 degree to 360 degrees; four fixing bolt holes 11 which are uniformly distributed are arranged on the fixing base 5, and a marking line 10 with a rotation angle of 0 degree is carved along the diameter direction of the base.
The testing method of the metal matrix composite fiber ejection testing device comprises the following steps:
1) preparing a sample with two parallel end surfaces, the end surfaces vertical to the length direction of the fiber and the thickness of 0.1-0.7 mm;
2) selecting a high-load module of a nanoindenter, and installing a conical flat pressing head; a conical flat pressure head with the plane diameter of 50 μm; the load of the high-load module is 100 mN-30N.
3) Carrying out air compression calibration on the indentation shaft; the indentation axis air compression calibration should be performed before testing after each sample change.
4) Calibrating the relative position of the needle point and the optical lens: installing an aluminum sample on a nano indenter test platform, pressing a single or a group of indentations on the aluminum sample, finding the indentations under a nano indenter optical lens, checking whether the center of an X, Y-axis cross marking line at the central position of the optical lens field coincides with the set indentation position, and if the center deviates, adjusting to completely coincide;
5) placing the sample on a sample placing platform, and unifying X, Y axes of the sample and a coordinate system of a test device platform by using a centering identification line for the sample with a regular shape; placing the area where the fibers to be subjected to the ejection test are located above the circular groove 8, and rotating the manual adjusting ring 3 clockwise to enable the two clamping jaws 1 to move downwards to clamp the edge of the sample and fix the sample to be tested;
6) adsorbing or fixing a fixing base 5 of the testing device on a nano-indenter testing platform by adopting a bolt;
7) focusing the surface of a sample on an optical lens observation interface of the nanoindentor, setting a working area boundary, and setting a test range capable of performing an ejection test, namely a nanoindentor working area, according to the position of a clamping jaw;
8) Observing the overall appearance of a sample in a working area at a light mirror observation interface, selecting fibers needing to be subjected to ejection test testing, and coinciding the center of the cross section of the target fiber with the center of a X, Y-axis cross identification line at the center position of a light mirror view field of a nano indenter by adjusting the X, Y axis of a nano indenter testing platform and the rotation angle of a corner adjusting base;
9) under an indentation module of a nano indenter, a displacement control mode is selected, a loading function is trapezoidal loading, and a loading curve comprises the following steps: setting maximum displacement, loading time and unloading time, starting the test, simultaneously setting a plurality of fiber ejection positions, and recording coordinates;
10) after the test is finished, starting from the set first position, obtaining a force-displacement curve by using an analysis module of nanoindenter software, and obtaining information such as the length of the ejected fiber and the deformation amount of a matrix near the fiber by using the in-situ imaging function of the nanoindenter;
11) the hand adjusting ring 3 is rotated counterclockwise to move the two claws 1 upward, and the sample is removed from the cylindrical sample placement platform 2 by tweezers and loaded into a sample cell.
The test sample is a fiber reinforced metal matrix composite, the test sample is one of round, oval, square, rectangular or irregular sheet-shaped forms, the test plane is the cross section of the composite test sample vertical to the length direction of the fiber, the thickness of the test sample is 0.1-0.5 mm, and the diameter of the fiber is 50-150 μm.
Example 1
As shown in fig. 1 to 3, a metal matrix composite fiber ejection test apparatus for nanoindentation includes: symmetry jack catch 1, cylindric sample place the platform 2, hand adjust ring 3, corner adjust base 4 and unable adjustment base 5, wherein:
the center position of 2 terminal surfaces of cylindric sample place the platform has circular recess 8, and jack catch 1 edge is flushed with circular recess 8 edge, is drawn the mark line 6 that the cross-section of being convenient for is circular sample centering and the mark line 7 of square sample centering respectively to and be used for unifying the perpendicular cross groove 22 of sample coordinate system and test system coordinate system. The metal matrix composite sample to be measured is placed above the circular groove in the surface of the platform, the hand adjusting ring 3 rotates clockwise, the groove 15 drives the circular ring piece 14 to move downwards, the spring 13 is tensioned, vertical downward pulling force is applied to the clamping jaw 1, and thus the sample is fixed on the edge of the sample. Connect cylindric sample place the platform 2 and corner through bolt firmware 21 and step 19, 20 and adjust base 4, corner is adjusted base 4 and unable adjustment base 5 and is ferromagnetic material, connects through step 18 and the magnetic force that receives, and rotatory corner is adjusted base 4 and is driven sample place the platform 2 rotation, drives the rotary motion of sample, and it is unified with the X, Y axle cross groove in the nanometer indentation test system screen of X, Y axle of sample coordinate system. When a sample is unloaded, the hand adjusting ring 3 is rotated anticlockwise, the reverse groove 15 drives the circular ring piece 14 to move upwards, after the circular ring piece contacts the pin 12, the hand adjusting ring is continuously rotated, the claw is jacked up by the pin, and the sample is taken down.
Preferably, the test sample is a fiber reinforced metal matrix composite, the thickness of the test sample is 0.1 mm-0.7 mm, and the fiber diameter is 50 μm-150 μm.
Preferably, the circular groove 8 is located at the center of the cylindrical sample placement platform 2, and the diameter of the groove is 2mm to 5 mm.
In a preferred embodiment, the height of the claw 1 protruding from the cylindrical sample-placing table 2 in the clamped state is 0.5mm to 1.5 mm.
Preferably, the fixing base 5 and the rotation angle adjusting base 4 are made of martensitic stainless steel, and the symmetrical clamping jaws 1, the cylindrical sample placing platform 2 and the manual adjusting ring 3 are made of austenitic stainless steel.
Example 2
This example uses SiC f The fiber ejection test method comprises the following steps:
1) preparing SiC with two parallel end faces, the end faces vertical to the length direction of the fiber and the thickness of about 0.2mm f The Ti metal matrix composite test specimen.
2) A high-load module of the nanoindenter is selected, and a Conical Flat indenter (Flat end conventional) is installed, wherein the plane diameter of the indenter is 50 mu m.
3) And opening the nano-indenter, entering an operation interface, and performing indentation axis Air compression calibration (Air index).
4) Calibrating the relative position of the needle point and the optical lens: the aluminum standard sample is installed on a nano indenter test platform, an indentation is pressed on the aluminum standard sample, then the aluminum standard sample is found under a nano indenter optical lens, whether the center of the X, Y-axis cross marking line at the central position of the optical lens field coincides with the set indentation position or not is checked, and if the center deviates, the aluminum standard sample is adjusted to be completely coincident.
5) The sample is placed on a sample placing platform, the center of the cross section of the sample coincides with the center of a circular centering identification line, about 90% of the area where the fibers are located is located above a circular groove, the outer ring fibers and the sheath area are lapped on the platform, and the hand adjusting ring is rotated clockwise to enable the two clamping jaws to move downwards, clamp the edge of the sample and fix the sample to be detected.
6) And adsorbing the fixing base of the testing device on a nano-indenter testing platform.
7) And focusing the surface of the sample on an optical lens observation interface of the nanoindenter, and setting the boundary of a working area. The edge of the claw is opposite to the edge of the groove of the sample placing platform, so that the circular range corresponding to the two claws is set, and the circular range is a test range capable of carrying out an ejection test, namely a working area of the nanoindenter.
8) Observing the overall appearance of a sample in a working area on an optical lens observation interface, selecting fibers needing to be subjected to ejection test testing, adjusting the rotation angles of an X, Y shaft and a corner adjusting base of a nano indenter testing platform, coinciding the center of a target fiber section with the center of a X, Y shaft cross identification line of the central position of an optical lens field of a nano indenter, recording the coordinate value displayed by the optical lens position, searching and setting the next fiber position for ejection test, and so on, and completing the setting of all fiber positions of the section to be tested, which need to be subjected to ejection test testing.
9) Under an indentation module of a nano indenter, a displacement control mode is selected, a loading function is trapezoidal loading (linear loading-load retention-linear unloading), the maximum displacement is set to be 10000nm, the loading time is set to be 10s, the load retention time is set to be 5s, the unloading time is set to be 10s, and the test is started.
10) After the test is finished, starting from the set first position, obtaining a force-displacement curve by using an analysis module of nano-indenter software, and obtaining information such as the length of the ejected fiber and the deformation amount of a matrix near the fiber by using the in-situ imaging function of the nano-indenter.
11) The hand adjusting ring is rotated counterclockwise to move the two claws upward, and the sample is taken off from the cylindrical sample placing platform by using tweezers and is loaded into a sample box. The sample can be directly placed into a scanning electron microscope, and the recorded coordinates are utilized to position the fiber subjected to the ejection test, observe the surface appearance and analyze the micro-area elements. And in addition, after the observation of the scanning electron microscope, the positions where the fiber ejection test needs to be carried out are considered to be supplemented, after the coordinates are recorded, the steps 2) to 11) are repeated, and the same sample is subjected to repeated tests.
Example 3
In this example, the composite test sample was SiC f The fiber of the/Ti composite material is SiC f The method comprises the following steps of:
1) And selecting a standard load module of the nanoindenter, and installing the Berkovich indenter.
2) And opening the nano-indenter, entering an operation interface, and performing indentation axis Air compression calibration (Air index).
3) Calibrating the relative position of the needle point and the optical lens: the aluminum standard sample is arranged on a nano indenter test platform, an indentation is pressed on the aluminum standard sample, then the aluminum standard sample is found under a nano indenter optical lens, whether the center of the X, Y-axis cross marking line at the central position of the optical lens view field coincides with the set indentation position or not is checked, and if the center deviates, the aluminum standard sample is adjusted to be completely coincident.
4) And placing the sample on a sample placing platform, placing a crack area in the sample above the circular groove, overlapping outer ring fibers and a sheath area on the platform, clockwise rotating the hand adjusting ring to enable the two clamping jaws to move downwards, clamping the edge of the sample and fixing the sample to be detected.
5) And adsorbing the fixing base of the testing device on a nano-indenter testing platform.
6) And focusing the surface of the sample on an optical lens observation interface of the nanoindenter, and setting a working area boundary according to the crack position of the sample to be detected.
7) And at the observation interface of the optical lens, the crack position is moved to the central position of the optical lens field of the nanoindenter by adjusting the X, Y axis of the nanoindenter test platform. The corner adjusting base is rotated to drive the hand adjusting ring and the sample placing platform to rotate, a corner scribing line with the interval of 1 degree is arranged on the corner adjusting base at the angle of 0-360 degrees, and a marking line with the angle of 0 degree is carved along the diameter direction of the fixed base. And rotating the corner adjusting base in the reverse direction according to the deflection angle between the crack propagation direction and the X axis, and rotating the crack propagation direction to coincide with the X axis of the nanoindenter testing platform through the rotating motion of the sample placing platform.
8) Under an automatic test interface, dot matrixes with the interval of 5 microns of 40 multiplied by 1 are set by taking the intersection point of X, Y axis cross scribe lines in an optical mirror as a starting point.
9) Under an indentation module of a nano indenter, selecting a load control mode, setting a loading function as trapezoidal loading (linear loading-load retention-linear unloading), setting the maximum load to be 5mN, the loading time to be 5s, the load retention time to be 2s and the unloading time to be 5s, and starting the test.
10) After the test is finished, the data are processed in batch by using an analysis module of the nanoindenter software, a group of hardness and constraint modulus values distributed along the crack propagation direction are obtained, and a corresponding contact depth curve (force-displacement curve) is obtained.
11) The hand adjusting ring is rotated counterclockwise to move the two claws upward, and the sample is taken off from the cylindrical sample placing platform by using tweezers and is loaded into a sample box. The sample can be directly placed into a scanning electron microscope, the recorded coordinates are utilized to position the crack position for testing the hardness distribution, the microstructure morphology of the crack area is observed, and the micro-area element distribution is analyzed.
The method is simple to operate, can effectively prevent sample pollution and damage caused by the test process, and improves the accuracy and the working efficiency of the metal matrix composite fiber ejection test. In addition, the research idea provided by the invention can be conveniently expanded and applied to other material sheet samples for carrying out indentation and scratch tests of the nano-indenter.
The above description describes some preferred embodiments of the invention, however, it should be noted that: it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the principles of the invention, and such changes and modifications are to be considered within the scope of the invention.
Claims (10)
1. The utility model provides a metal matrix composite fibre ejection test device for nanoindentation which characterized in that: the device comprises symmetrical clamping jaws 1, a cylindrical sample placing platform 2, a manual adjusting ring 3, a corner adjusting base 4 and a fixed base 5; a circular groove 8 is formed in the center of the end face of the cylindrical sample placing platform 2, the symmetrical clamping jaws 1 are installed in through grooves symmetrically formed in the cylindrical sample placing platform 2, the clamping ends of the symmetrical clamping jaws 1 are similar to a trapezoidal body, the outer sides of the clamping ends are rounded rectangles, the bottom edges of the inner sides are circular arcs concentric with the groove 8, the radius of the circular arcs is equal to that of the groove 8, the plane where the upper circular arcs are located is parallel to the bottom face, and the bottom angle of the side of the circular arc of the trapezoidal body is 45 degrees; the cylindrical sample placing platform 2 is connected with a bolt fastener 21 through a step 19 and a step 20 on the corner adjusting base 4; a magnet 16 is arranged at the center of the fixed base 5 and connected through a wedge-shaped bolt fastener 17, and the corner adjusting base 4 is connected with the magnetic force applied through a step 18 on the fixed base 5; the manual adjusting ring 3 is in threaded connection with the cylindrical sample placing platform 2, a reverse groove 15 is formed in the lower portion of the manual adjusting ring 3, the circular ring piece 14 is clamped in the groove, and the symmetrical clamping claws 1 are fixedly connected with the circular ring piece 14 through springs 13; an elongated pin 12 is placed in the middle of the spring, the length of the pin corresponding to the relaxed state length of the spring.
2. The metal matrix composite fiber ejection test device for the nanoindenter of claim 1, characterized in that: the circular groove 8 is positioned in the center of the cylindrical sample placing platform 2, and the diameter of the groove is 2-5 mm.
3. The metal matrix composite fiber ejection test device for the nanoindenter of claim 1, characterized in that: under the clamping state, the height of the clamping jaw 1 higher than the cylindrical sample placing platform 2 is 0.5 mm-1.5 mm.
4. The metal matrix composite fiber ejection test device for the nanoindenter of claim 1, characterized in that: the fixed base 5 and the corner adjusting base 4 are made of martensitic stainless steel in ferromagnetic materials, and the symmetrical clamping jaws 1, the cylindrical sample placing platform 2 and the manual adjusting ring 3 are made of austenitic stainless steel.
5. The metal matrix composite fiber ejection test device for the nanoindenter of claim 1, characterized in that: the surface of the cylindrical sample placing platform 2 is respectively provided with an identification line 6 which is convenient for centering a round sample and an identification line 7 which is convenient for centering a square sample in cross section, and a vertical cross-shaped scribing line 22 which is used for unifying a sample coordinate system and a test system coordinate system.
6. The metal matrix composite fiber ejection test device for the nanoindenter of claim 1, characterized in that: the surface of the manual adjusting ring 3 is provided with anti-skid threads; the corner adjusting base 4 is provided with corner scribed lines 9 with the intervals of 1 degree ranging from 0 degree to 360 degrees; four fixing bolt holes 11 which are uniformly distributed are arranged on the fixing base 5, and a marking line 10 with a rotation angle of 0 degree is carved along the diameter direction of the base.
7. The testing method of the metal matrix composite fiber ejection testing device according to any one of claims 1 to 6, characterized by comprising the steps of:
1) preparing a sample with two parallel end surfaces, the end surfaces vertical to the length direction of the fiber and the thickness of 0.1-0.7 mm;
2) selecting a high-load module of a nanoindenter, and installing a conical flat pressing head;
3) carrying out air compression calibration on the indentation shaft;
4) calibrating the relative position of the needle point and the optical lens: installing an aluminum sample on a nano indenter test platform, pressing a single or a group of indentations on the aluminum sample, finding the indentations under a nano indenter optical lens, checking whether the center of an X, Y-axis cross marking line at the central position of the optical lens field coincides with the set indentation position, and if the center deviates, adjusting to completely coincide;
5) Placing the sample on a sample placing platform, and unifying X, Y axes of the sample and a coordinate system of a test device platform by using a centering identification line for the sample with a regular shape; placing the area where the fibers to be subjected to the ejection test are located above the circular groove 8, and rotating the manual adjusting ring 3 clockwise to enable the two clamping jaws 1 to move downwards to clamp the edge of the sample and fix the sample to be tested;
6) adsorbing or fixing a fixing base 5 of the testing device on a nano-indenter testing platform by adopting a bolt;
7) focusing the surface of a sample on an optical lens observation interface of the nanoindentor, setting a working area boundary, and setting a test range capable of performing an ejection test, namely a nanoindentor working area, according to the position of a clamping jaw;
8) observing the overall appearance of a sample in a working area at a light mirror observation interface, selecting fibers needing to be subjected to ejection test testing, and coinciding the center of the cross section of the target fiber with the center of a X, Y-axis cross identification line at the center position of a light mirror view field of a nano indenter by adjusting the X, Y axis of a nano indenter testing platform and the rotation angle of a corner adjusting base;
9) under the indentation module of the nanoindentor, a displacement control mode is selected, a loading function is trapezoidal loading, and a loading curve comprises: setting maximum displacement, loading time and unloading time, starting the test, simultaneously setting a plurality of fiber ejection positions, and recording coordinates;
10) After the test is finished, starting from the set first position, obtaining a force-displacement curve by using an analysis module of nanoindenter software, and obtaining information such as the length of the ejected fiber and the deformation quantity of a matrix near the fiber by using the in-situ imaging function of the nanoindenter;
11) the hand adjusting ring 3 is rotated counterclockwise to move the two claws 1 upward, and the sample is removed from the cylindrical sample placement platform 2 by tweezers and loaded into a sample cell.
8. The testing method of the metal matrix composite fiber ejection testing device according to claim 7, wherein the conical flat indenter used in the step 2) has a plane diameter of 50 μm; the load of the high-load module is 100 mN-30N.
9. The testing method of the metal matrix composite fiber ejection testing device according to claim 7, wherein the indentation axis air compression calibration in the step 3) is performed before the test after each sample replacement.
10. The method for testing the fiber ejection test device of the metal matrix composite for the nanoindenter according to claim 7, wherein the sample is a fiber-reinforced metal matrix composite, the sample is one of a sheet-like shape of a circle, an ellipse, a square, a rectangle, or an irregular shape, the test plane is a cross section of the composite sample perpendicular to a fiber length direction, the thickness of the sample is 0.1mm to 0.5mm, and the fiber diameter is 50 μm to 150 μm.
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| CN202210353128.0A CN114839039A (en) | 2022-04-02 | 2022-04-02 | Metal matrix composite fiber ejection test device and test method |
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| CN202210353128.0A CN114839039A (en) | 2022-04-02 | 2022-04-02 | Metal matrix composite fiber ejection test device and test method |
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