CN112067462A - Method and device for prefabricating cracks on ultrathin brittle material - Google Patents
Method and device for prefabricating cracks on ultrathin brittle material Download PDFInfo
- Publication number
- CN112067462A CN112067462A CN202010948883.4A CN202010948883A CN112067462A CN 112067462 A CN112067462 A CN 112067462A CN 202010948883 A CN202010948883 A CN 202010948883A CN 112067462 A CN112067462 A CN 112067462A
- Authority
- CN
- China
- Prior art keywords
- crack
- loading
- notch
- width
- sample
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000000034 method Methods 0.000 title claims abstract description 59
- 239000000463 material Substances 0.000 title claims abstract description 52
- 239000002184 metal Substances 0.000 claims abstract description 49
- 239000002131 composite material Substances 0.000 claims abstract description 36
- 239000000758 substrate Substances 0.000 claims abstract description 24
- 230000008569 process Effects 0.000 claims abstract description 19
- 238000004519 manufacturing process Methods 0.000 claims abstract description 9
- 238000012544 monitoring process Methods 0.000 claims abstract description 5
- 238000012545 processing Methods 0.000 claims abstract description 5
- 239000011159 matrix material Substances 0.000 claims description 29
- 238000013001 point bending Methods 0.000 claims description 21
- 230000033001 locomotion Effects 0.000 claims description 10
- 239000011521 glass Substances 0.000 claims description 5
- 238000005336 cracking Methods 0.000 claims description 3
- 238000006073 displacement reaction Methods 0.000 claims description 3
- 238000005452 bending Methods 0.000 abstract 1
- 239000000919 ceramic Substances 0.000 description 12
- 238000012360 testing method Methods 0.000 description 7
- 238000001514 detection method Methods 0.000 description 6
- 230000000694 effects Effects 0.000 description 6
- 238000011065 in-situ storage Methods 0.000 description 6
- 238000013461 design Methods 0.000 description 5
- 230000009471 action Effects 0.000 description 3
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 3
- 229910052593 corundum Inorganic materials 0.000 description 3
- 238000005520 cutting process Methods 0.000 description 3
- 230000007547 defect Effects 0.000 description 3
- 229910001845 yogo sapphire Inorganic materials 0.000 description 3
- 229910001369 Brass Inorganic materials 0.000 description 2
- 239000010951 brass Substances 0.000 description 2
- 238000005524 ceramic coating Methods 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 238000002789 length control Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000003287 optical effect Effects 0.000 description 2
- 238000009417 prefabrication Methods 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 230000003068 static effect Effects 0.000 description 2
- 229920000742 Cotton Polymers 0.000 description 1
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007123 defense Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 238000007656 fracture toughness test Methods 0.000 description 1
- 239000003292 glue Substances 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 238000007373 indentation Methods 0.000 description 1
- 230000000977 initiatory effect Effects 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 230000001151 other effect Effects 0.000 description 1
- 238000011056 performance test Methods 0.000 description 1
- 238000012805 post-processing Methods 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 230000000644 propagated effect Effects 0.000 description 1
- 230000001902 propagating effect Effects 0.000 description 1
- 238000012797 qualification Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000010008 shearing Methods 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
Images
Classifications
-
- 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
- G01N3/20—Investigating strength properties of solid materials by application of mechanical stress by applying steady bending forces
-
- 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
- G01N3/02—Details
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0014—Type of force applied
- G01N2203/0023—Bending
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0058—Kind of property studied
- G01N2203/006—Crack, flaws, fracture or rupture
- G01N2203/0062—Crack or flaws
- G01N2203/0066—Propagation of crack
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0058—Kind of property studied
- G01N2203/0076—Hardness, compressibility or resistance to crushing
- G01N2203/0087—Resistance to crushing
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/02—Details not specific for a particular testing method
- G01N2203/026—Specifications of the specimen
- G01N2203/0262—Shape of the specimen
- G01N2203/0278—Thin specimens
- G01N2203/0282—Two dimensional, e.g. tapes, webs, sheets, strips, disks or membranes
Abstract
The invention mainly aims to provide a method and a device for prefabricating cracks on an ultrathin brittle material. The method comprises the following steps: processing the brittle material into a cuboid sample; adhering the sample wafer to the metal substrate to obtain a composite body; manufacturing a notch on the long edge of one side of the sample wafer; the composite body comprises a first side surface and a second side surface, wherein the first side surface is close to the notch, and the second side surface is arranged on the other side of the two side surfaces of the long side; bending and loading four points of the first side surface and the second side surface along the horizontal direction to manufacture an initial crack; loading the composite body to manufacture an initial crack, and enabling the interval of the first side surface, which comprises the notch, to be in a tension area; and slowly loading, monitoring the crack image in real time, and unloading when the prefabricated crack reaches the target length. The technical problem to be solved is to control the crack length of the prefabricated crack of the ultrathin brittle material and monitor the crack propagation process in real time; the method is simple and convenient to operate, saves the process time, and is more practical.
Description
Technical Field
The invention belongs to the technical field of ceramic fracture toughness testing, and particularly relates to a method and a device for prefabricating cracks on an ultrathin brittle material.
Background
Ultrathin brittle materials such as ceramic coatings, ultrathin ceramics (ceramic substrates) and ultrathin glass materials have excellent characteristics of high temperature resistance, wear resistance, corrosion resistance and the like, and are widely applied to the fields of mechatronics, aerospace, national defense and military industry and the like. For ultrathin brittle materials, accurate evaluation of the crack propagation process and fracture toughness of the material is of great significance for understanding the reliability and safety application of the material.
Numerous studies at home and abroad indicate that the creation of an initial crack with a proper length is crucial for accurately evaluating the fracture toughness of a material. However, due to the low toughness and high elastic modulus of brittle materials, it is difficult to control crack initiation and crack arrest during pre-cracking. For most brittle materials, macrocracks propagate rapidly once they initiate under static load. Thus, small ceramic samples tend to exhibit catastrophic fracture or no fracture when pre-fractured.
In the prior art, a plurality of crack prefabricating methods for block materials are provided, such as a bridge pressing method, a static expansion method, a bevel cutting method and the like, but the methods cannot be used for crack prefabricating of ultrathin materials. Aiming at the preparation of the pre-cracks of the ultrathin material, a widely adopted method at home and abroad is to bond a sample and a metal matrix to form a complex, then carry out three-point bending test on the complex, and detect the generation of the cracks by matching with an acoustic emission detection system. Although this method can be used to perform the crack, it has the following drawbacks: the prefabricated crack direction is difficult to control, and the prefabricated qualified rate of cracks is low; when the acoustic emission detection system judges a prefabrication end point, the sound is produced when the prefabrication crack succeeds, and then the sound wave transmission, the computer screen reaction and result display, the unloading according to the result and other series of operations are needed, so that the unloading has hysteresis, generally, the time lags by at least two seconds and three seconds, and the crack continues to expand in the lagged time period, so that the length of the crack is difficult to control; meanwhile, characteristic data of a crack propagation process cannot be acquired, and the performance of the material is not comprehensively mastered.
Disclosure of Invention
The invention mainly aims to provide a method and a device for prefabricating cracks on an ultrathin brittle material, aiming at solving the technical problems that the crack length of the prefabricated cracks on the ultrathin brittle material is controlled, the qualified rate (the length size of the prefabricated cracks is regarded as being qualified when being in the length range required by fracture toughness measurement, namely 0.35-0.6 time of the width size of a test piece) is nearly hundred percent, and the process of crack propagation can be monitored in real time; the method is simple and convenient to operate, saves the process time, and is more practical.
The purpose of the invention and the technical problem to be solved are realized by adopting the following technical scheme. The invention provides a method for prefabricating cracks on an ultrathin brittle material, which comprises the following steps:
1) processing a brittle material into a sample wafer in a cuboid shape, wherein the thickness of the sample wafer is less than or equal to 1 mm;
2) pasting the sample piece on a metal matrix in a cuboid shape to obtain a complex; wherein the long edge of the sample wafer is parallel to the long edge of the metal matrix; width of the coupon < width of the metal substrate; the length of the sample wafer is less than or equal to that of the metal matrix; the bottom surface of the sample wafer is completely positioned on the top surface of the metal matrix;
3) making a notch on the long edge of one side of the sample wafer; the composite body comprises two side surfaces of a long side, wherein the side surface close to the notch is a first side surface, and the other side surface is a second side surface;
4) loading the composite body to manufacture an initial crack, and enabling the interval of the first side surface, which comprises the notch, to be in a tension area;
5) and slowly loading, and monitoring the crack image in real time until the crack reaches the target length of the prefabricated crack.
The object of the present invention and the technical problems solved thereby can be further achieved by the following technical measures.
Preferably, the method described above, wherein the loading in step 4) is a four-point bending loading of the first side and the second side of the composite in a horizontal direction; wherein the two force points A, B applied to the first side are located on either side of the notch, and the two force points C, D applied to the second side are located between A and B and on either side of the notch.
Preferably, in the method, a ratio of the target length of the pre-crack to the width of the sample wafer is 0.4 to 0.6.
Preferably, in the method, the ratio of the width of the metal substrate to the width of the sample wafer is 1.2 to 1.7; the thickness of the metal substrate is 3/4 times its width.
Preferably, in the method, the notch is located in the middle of the long side of the sample wafer, and the position fluctuation range is less than or equal to 3%.
Preferably, the method further comprises a step of cutting the sample sheet into a plurality of cut pieces, wherein the size of the cut pieces in the width direction of the sample sheet is not more than 0.1 times the width of the sample sheet.
Preferably, in the method, one long side of the sample wafer is located in the second side face.
Preferably, in the method, the slow loading is displacement loading, and the loading speed is 0.05-0.1 mm/min.
The object of the present invention and the technical problem to be solved are also achieved by the following technical means. According to the present invention, there is provided an apparatus for prefabricating cracks, which includes:
a fixing jig including a first supporting unit and a second supporting unit connected to each other; the first supporting unit is provided with a platform for placing a processed workpiece; the second supporting unit comprises two symmetrically arranged supporting parts; one side of the supporting part facing the platform is an arc surface; when a workpiece to be processed is placed on the platform, the cambered surface of the supporting part is in line contact with the workpiece to be processed in the vertical direction;
the movable pressure head is arranged on one side of the platform, can move in the horizontal direction and comprises two symmetrically arranged convex parts; one side of the convex part facing the platform is an arc surface; when a workpiece to be processed is placed on the platform, the cambered surface of the protruding part is in line contact with the workpiece to be processed in the vertical direction; the two supporting parts and the two protruding parts are respectively positioned on opposite sides of the platform and can provide four-point bending load which is in accordance with GB/T6569 for a workpiece placed on the platform;
a tool microscope including a stage and an observation mirror; and a horizontal loading device consisting of a fixed clamp and a movable pressure head is arranged on the workbench, and the crack propagation process of the processed workpiece is monitored in real time through the observation sight glass.
The object of the present invention and the technical problems solved thereby can be further achieved by the following technical measures.
Preferably, the apparatus of the preceding paragraph, wherein the movement of the movable ram comprises a rotational movement in a horizontal direction and a translational movement in a horizontal direction.
Preferably, in the aforementioned device, the arc surface of the protruding part and the arc surface of the supporting part are both arc surfaces.
Preferably, the device of the preceding paragraph, wherein the distance between two of said projecting members is less than the distance between two of said support members.
By the technical scheme, the method and the device for prefabricating the cracks on the ultrathin brittle material provided by the invention at least have the following advantages:
1. according to the method and the device for prefabricating the crack on the ultrathin brittle material, the ultrathin brittle carrier is pasted on the metal matrix, four-point bending load is applied to the metal matrix to generate a tensile area, then the width size and the load application speed of the sample wafer in the tensile area are controlled, the crack propagation process is monitored in real time through a tool microscope, the crack can be timely unloaded when the crack reaches the target length, the in-situ observation of the crack propagation of the ultrathin brittle material is realized, the crack propagation characteristic of the brittle material can be comprehensively mastered, and the length of the crack can be accurately controlled.
2. The invention provides a method and a device for prefabricating cracks on an ultrathin brittle material, which are characterized in that a micro-defect is manufactured on one long side of a sample wafer, the micro-defect is used as a starting point of crack propagation, the prefabricated crack on the sample wafer is ensured to propagate on the preset position, and the crack position is accurate.
3. According to the method and the device for prefabricating the crack of the ultrathin brittle material, provided by the invention, the preset area for crack propagation on the sample wafer is uniformly stressed by four-point bending loading and controlling the notch position of the micro-defect, the crack propagation can be slowly propagated along the direction vertical to the long edge, and the direction of the prepared crack is controlled.
4. According to the method and the device for prefabricating the crack on the ultrathin brittle material, the width size of the sample in a tensile area can be flexibly adjusted by controlling the width ratio of the metal matrix to the sample, so that the size of the initial crack is controlled, then the crack is slowly loaded and continuously expanded on the basis of the initial crack, and the success rate of prefabricating the crack on the ultrathin brittle material is almost one hundred percent.
5. According to the method and the device for prefabricating the cracks on the ultrathin brittle material, the cracks with the positions, the directions and the sizes meeting the requirements are prepared through the technical scheme, and the sample wafer can be directly used for subsequent performance tests by controlling the pasting position of the sample wafer to be aligned and tightly pasted with three surfaces of the metal matrix without post-processing treatment of a test sample. The horizontal loading device is simple to manufacture and is economical in cost; the crack image can be monitored in real time by matching with a commercially available tool microscope, and the crack propagation process can be mastered in real time. The method is simple and convenient to operate, and saves the process time.
The foregoing description is only an overview of the technical solutions of the present invention, and in order to make the technical solutions of the present invention more clearly understood and to implement them in accordance with the contents of the description, the following detailed description is given with reference to the preferred embodiments of the present invention and the accompanying drawings.
Drawings
FIG. 1 is a flow chart of the process for preparing the workpiece made of the ultra-thin brittle material according to the present invention;
FIG. 2 is a schematic structural diagram of a pre-crack apparatus according to the present invention;
FIG. 3 shows Al in the examples of the present invention2O3A top view of a sample wafer made of a ceramic substrate;
FIG. 4 is a top view of a composite of a coupon and a metal substrate according to an embodiment of the present invention;
FIG. 5 is a top view of a microdefect made on a composite surface sample in an embodiment of the present invention;
FIG. 6 is a top view of a composite after pre-cracking in accordance with an embodiment of the present invention.
Detailed Description
To further illustrate the technical means and effects of the present invention for achieving the predetermined objects, the following detailed description of the method and apparatus for performing a crack on an ultra-thin brittle material according to the present invention, and the detailed embodiments, structures, features and effects thereof will be provided with reference to the accompanying drawings and preferred embodiments.
The invention provides a method for prefabricating cracks on an ultrathin brittle material, which comprises the following steps as shown in the attached figure 1: 1) processing a brittle material into a sample sheet 1 in a cuboid shape, wherein the thickness of the sample sheet 1 is less than or equal to 1 mm; 2) adhering the sample wafer 1 to a metal substrate 2 in a cuboid shape to obtain a complex 3; wherein, the long edge of the sample wafer 1 is parallel to the long edge of the metal matrix 2; width of the sample wafer 1 < width of the metal base 2; the length of the sample wafer 1 is less than or equal to that of the metal matrix 2; the bottom surface of the sample wafer 1 is completely positioned on the top surface of the metal matrix 2; 3) making a notch 31 on the long side of one side of the sample wafer 1; the composite body comprises two side surfaces of a long side, wherein the side surface close to the notch is a first side surface, and the other side surface is a second side surface; 4) loading the composite body to manufacture an initial crack, and enabling the interval of the first side surface, which comprises the notch, to be in a tension area; 5) and slowly loading, and monitoring the crack image in real time until the crack reaches the target length of the prefabricated crack.
The brittle material in the above technical solution includes, but is not limited to, a ceramic coating, an ultra-thin ceramic (a ceramic substrate, etc.), an ultra-thin glass material, and the like. When the brittle materials are different, the requirements on the thickness of the sample are also different, and the invention especially defines the ultrathin brittle material as the brittle material with the thickness less than or equal to 1 mm.
According to the technical scheme, the crack image is monitored in real time to judge the end point of crack propagation, so that the development degree of cracks can be known in real time, more attention can be focused before the cracks develop to reach the end point, and the unloading time is strictly controlled; meanwhile, the loading speed is very slow, the crack propagation is immediately stopped when the crack is unloaded, and the crack cannot be stopped due to hysteresis caused by inertia and the like; through the cooperation of the above means, the length control of the prefabricated crack is more accurate.
When the sample wafer is pasted on the metal base body, the sample wafer is pasted symmetrically in the length direction as much as possible, the two ends of the sample wafer extending out of the metal base body are avoided, the design limitation aims at considering that the vertical shearing action is caused by the gravity action of the sample wafer after the sample wafer extends out of the metal base body, and therefore the effect of the prefabricated crack is influenced.
Preferably, the loading in the step 4) is to perform four-point bending loading on the first side and the second side of the composite body along the horizontal direction to manufacture an initial crack; wherein the two force points A, B applied to the first side are located on either side of the notch, and the two force points C, D applied to the second side are located between A and B and on either side of the notch.
The attaching position of the sample in the width direction has a close relationship with the pre-crack. When the composite body is loaded in four-point bending, the metal matrix is subjected to the combined action of A, B, C and D four-point forces, and is delimited by the middle position of the first side face and the second side face, and the half of the metal matrix, which is close to the first side face, is in a tension area; the width dimension of the sample wafer in the tension area can be accurately controlled by adjusting the position relation of the sample wafer and the metal matrix in the width direction; and when the sample is pasted, controlling the width dimension of the sample sheet in the tension area to be larger than the length of the initial crack.
The notch is used as the starting point of the crack of the pre-crack, therefore, when the notch is made, the preset position of the target crack is firstly selected, and then the notch is made at the intersection point of the preset position of the crack and the long edge of the sample sheet close to the first side surface, so that the position of the crack developed by the notch is controlled.
The composite was placed on the stage of the test apparatus with the sample side facing upward and the metal substrate facing downward, and the composite was subjected to four-point bending loading by applying loads at points A, B, C and D in the horizontal direction. It should be noted that although the force points A, B, C and D are called force points, since the clamp and the ram of the horizontal loading device are both cylindrical or arc-shaped with a certain length, the contact positions with the first side and the second side of the composite body are actually line contact when the four-point bending loading is performed. During four-point bending loading, A, B points are located on both sides of the defect on the first side, and the area of the sample wafer between A, B points is uniformly stressed; C. d, the two points are positioned on two sides of the defect on the second side surface, and the area of the sample between the C, D points is uniformly stressed; through the comprehensive effect of the four-point stress, the half part of the composite body close to the first side surface is in a tensile area, so the sample wafer in the tensile area is also in a tensile state, the notch is also in the tensile area and is also in the tensile state, and therefore, the sample wafer can generate initial cracks under the condition of four-point bending loading.
The technical scheme of the invention particularly limits the stress direction of four-point bending loading to be stress in the horizontal direction, and aims to enable the crack of the sample wafer to expand in the horizontal direction, so that the dynamically developed crack can be placed under a tool microscope, the crack can be ensured to develop and can be directly observed in situ in real time, and the real-time crack image monitoring can be realized only by the existing tool microscope and other equipment in a laboratory, and high-price special equipment is not required to be configured, so that the cost is low.
Based on the defined conditions, the initial crack may be a crack that initiates propagation of the brittle material that is visibly observed under a microscope. When the composite is manufactured, the position relation between the sample wafer and the metal matrix in the width direction is controlled, so that the length of the initial crack can be controlled not to exceed the middle position between the first side surface and the second side surface, namely the width of the sample wafer in the tension area is larger than the length of the initial crack.
After the initial crack is formed, the crack is continuously and slowly expanded by controlling the magnitude of the four-point bending load, and the length of the crack is slowly prolonged. In the crack propagation process, the whole process is monitored in real time, the process characteristic of crack propagation is recorded at any time, the toughness/toughness characteristic of the material is mastered, and the length of the crack is monitored in real time. The crack is unloaded immediately when the crack length reaches a predetermined target length, at which time the crack stops propagating, so that a pre-crack with an accurately controlled length oriented perpendicular to the long side of the sample is obtained.
The magnifying display magnification of the tool microscope is 20-200 times; preferably, the magnifying display magnification of the tool microscope is 100 times.
Preferably, the ratio of the target length of the pre-crack to the width of the sample wafer is 0.4-0.6. When the fracture toughness is measured, the length of the prefabricated crack is required to be 0.35-0.6 times of the width of the brittle material in the detection standard. In order to improve the qualification rate of the prefabricated cracks, the size of the sample wafer is determined according to the target length of the prefabricated cracks when the sample wafer is manufactured, so that the prefabricated cracks on the sample wafer are ensured to meet the requirements and have good effect.
Preferably, the ratio of the width of the metal matrix to the width of the sample wafer is 1.2-1.7; the thickness of the metal substrate is 3/4 times its width.
The metal matrix has a width greater than the width of the coupon, and the purpose of this design is to ensure that the width of the coupon in the tension zone is adjustable. Setting the width ratio of the metal matrix to the sample wafer as m, wherein the width dimension of the sample wafer in the tension area is (1-m/2) -m/2 times of the width of the sample wafer, and if the width of the sample wafer is w, when the width ratio of the metal matrix to the sample wafer is 1.2, the width of the sample wafer in the tension area can be adjusted between 0.4w and 0.6 w; when the width ratio of the metal matrix to the sample is 1.7, the width of the sample in the tension area can be adjusted between 0.15w and 0.85 w. That is, the larger the width ratio of the metal matrix to the sample, the larger the range of the width dimension of the sample in the tension zone, and the larger the length adjustment range for making cracks. The width-thickness ratio of the metal matrix is limited to 4:3 in the technical scheme, and the purpose is to directly use the prepared prefabricated crack for subsequent tests of properties such as fracture toughness and the like so as to meet the detection requirements of national standards on test samples.
Preferably, the notch is positioned in the middle of the long edge of the sample wafer, and the position fluctuation range is less than or equal to 3%. Because the sample wafer between the stress points C and D is basically uniformly stressed when the four-point bending load is carried out, the effect of the prefabricated crack is not greatly influenced. The notch may be located as close as possible to the middle of the long side of the sample due to factors such as ease of installation of the device and composite for preparing the crack, and error in the operation for making the notch.
Preferably, the size of the notch along the width direction of the sample is not more than 0.1 times of the width of the sample.
The notch in the described solution is a micro-defect, which is of small size and is only used to locate the development of the pre-crack. The notches may be triangular or rectangular. The notch is preferably processed by an indentation method.
Preferably, one long side of the sample wafer is located in the second side face.
When the composite is manufactured, one long edge of a sample is aligned and adhered with the long edge of the metal substrate, and the design aims to consider that when the composite is used for detecting fracture toughness, the composite is directly taken for detection without continuously cutting and processing the composite.
Preferably, for convenience of operation, the length of the sample is the same as that of the metal substrate, in the composite body, one long side and two short sides of the sample are aligned with one long side and two short sides of the metal substrate and then are adhered, and three sides of the obtained composite body are tightly adhered.
Preferably, the slow loading adopts displacement loading, and the loading speed is 0.05-0.1 mm/min.
Control of the loading speed is critical when applying a load. On one hand, in order to control the crack propagation to be capable of slowly developing so as to ensure the stable propagation and accurate size of the crack, the slower the loading speed is, the more the slow propagation of the crack is required to be facilitated; on the other hand, too slow loading speed may affect the efficiency of the pre-crack. In the technical scheme of the invention, the requirement of the loading rate less than or equal to 0.1mm/min can meet the requirement of the prefabricated crack of the ultrathin brittle material aimed at by the invention, and the expansion direction and the crack length of the prepared prefabricated crack can be accurately controlled, thereby being beneficial to the subsequent detection of the performance of the brittle material and the accuracy of the result. On the other hand, on the premise of satisfying the above-mentioned crack growth control, the loading rate is required to be greater than or equal to 0.05mm/min in order to improve the working efficiency.
Preferably, the material of the metal matrix is brass.
The crack is prefabricated under a tool microscope through the technical scheme, and the crack is observed in situ in real time, so that the crack length is controlled. In order to visually observe the cracks on the sample sheet, after the cracks are prepared, dye penetrant solution is coated on the surface of the sample sheet, and the color of the surface of the sample sheet is wiped off by using a cotton swab and alcohol wiping. Repeating the above operations to allow the dye penetrant to penetrate into the preformed cracks, where a complete and clear colored line is visible to the naked eye, and the preformed cracks are controlled in position, direction and length to meet the standard requirements.
The present invention also provides an apparatus for prefabricating cracks, as shown in fig. 2, which includes:
a fixing jig 4 including a first supporting unit 41 and a second supporting unit connected to each other; the first supporting unit 41 is provided with a platform for placing a processed workpiece; the second support unit comprises two symmetrically arranged support members 42; the side of the supporting part 42 facing the platform is a cambered surface; when a workpiece is placed on the platform, the cambered surface of the supporting part 42 is in line contact with the workpiece in the vertical direction;
the movable pressure head 5 is arranged on one side of the platform, can move in the horizontal direction and comprises two symmetrically arranged convex parts 51; one side of the convex part 51 facing the platform is an arc surface; when a workpiece is placed on the platform, the cambered surface of the convex part 51 is in line contact with the workpiece in the vertical direction; the two supporting components 42 and the two protruding components 51 are respectively positioned at the opposite sides of the platform and can provide four-point bending load conforming to GB/T6569 for a workpiece placed on the platform;
a tool microscope 6 including a stage 61 and an observation mirror 62; a horizontal loading device consisting of a fixed clamp 4 and a movable pressure head 5 is arranged on the workbench 61; the observation mirror 62 is arranged above the worktable 61; the crack propagation process of the workpiece on the worktable 61 can be monitored in real time through the observation sight glass 62.
The four-point bending load specified in GB/T6569 is loaded in the vertical direction, while the load loaded in the four-point bending mode in the technical scheme of the invention is applied in the horizontal direction, namely the fixed clamp and the movable pressure head form a horizontal airborne device for loading. The structural design is aimed at enabling crack propagation to occur in the horizontal direction in a sample under four-point bending loading, thereby enabling real-time observation of crack propagation in situ through a tool microscope and enabling crack length control according to the observation result.
In the fixing clamp, the first supporting unit and the second supporting unit may be integrally formed or may be detachably connected.
The tool microscope is a mechanical optical instrument based on optical (microscope) aiming and coordinate (table) measurement, and can be used for measuring various lengths and angles. In the process of prefabricating the cracks on the machined workpiece, the crack propagation process can be monitored in real time in the whole process through the tool microscope, so that the characteristics of the brittle material can be comprehensively mastered.
Through parameter adjustment of the horizontal loading device, such as precise control of the loading speed, the crack of the processed workpiece can be slowly and stably expanded, and the expansion degree of the crack can be mastered at any time through the tool microscope. And unloading immediately when the crack propagation is monitored to reach the target length of the prefabricated crack, wherein the crack cannot be further expanded due to the inertia and other effects due to the control of crack propagation parameters, and the size of the crack is stabilized at the length of the unloaded crack, so that the accurate size of the prefabricated crack is ensured.
Preferably, the movement of the movable ram comprises a rotational movement in a horizontal direction and a translational movement in a horizontal direction.
The movable pressure head can rotate in the horizontal direction, so that the two protruding parts can be adjusted to be in close ground contact with a processed workpiece, the uniform stress of the area of the processed workpiece between the two protruding parts is ensured, and the accurate direction of the prefabricated crack is ensured. Meanwhile, the movable pressure head can also perform translational motion in the horizontal direction, and the loading speed of four-point bending is controlled by controlling the translational speed of the movable pressure head so as to control the crack propagation of the processed workpiece.
Preferably, the arc surface of the protruding part and the arc surface of the supporting part are both arc surfaces. The design of the convex part and the supporting part aims to consider that on one hand, the linear contact part can be flexibly adjusted along with the change of the shape when the convex part and the supporting part are in contact with the composite body, so that the convex part and the supporting part can be always in close contact and apply load, and on the other hand, the smooth transition of the arc surface can not damage the surface of a processed workpiece.
Preferably, the distance between two of said projecting members is less than the distance between two of said support members. The positions of the two supporting components in line contact with the processed workpiece are two stress points A, B on the first side surface of the complex; the locations where the two raised elements make line contact with the work piece are the two force points C, D on the second side of the composite.
This is further illustrated by the more specific examples below.
Example (b): al (Al)2O3Ceramic substrate crack preparation and in-situ observation
This example uses Al2O3The ceramic substrate as an ultra-thin brittle material was prepared into a sample piece having a rectangular parallelepiped shape with a length of 35.97mm, a width of 4.01mm and a thickness of 0.98mm, and its top view is shown in FIG. 3.
Adopting ergo glue to mix Al2O3The sample piece and one size of the ceramic substrate are as follows: the length is 36.01mm, the width is 6.03mm, and the thickness isA 3.98mm brass substrate was bonded such that one long side and two short sides of the coupon were aligned with one long side and two short sides of the metal substrate, and the top view of the resulting composite was as shown in fig. 4.
A triangular microdefect is formed on one long side of the sample piece of the composite body on the top surface of the metal substrate by using a microhardness tester, and the height of the triangular microdefect in the direction perpendicular to the long side is smaller than 1/10 of the width of the sample, as shown in fig. 5.
Placing the composite body with the micro defects on a platform of a prefabricated crack device for four-point bending loading, wherein when the composite body is placed, a sample wafer is required to be upward, and a metal matrix is required to be downward; wherein the second side of the composite body, which does not comprise the microdefect, faces to one side of the movable pressure head of the pre-crack device; the first side faces the second supporting unit.
Placing the horizontal loading device on a workbench of a tool microscope, observing the crack propagation process in real time by using the tool microscope, and loading the Al on the surface of the composite body2O3Forming main cracks on a sample wafer of the ceramic substrate, and controlling the length of the cracks by continuously and slowly loading (the loading speed is 0.08mm/min), thereby finally obtaining Al2O3The crack length on the ceramic wafer was 2.4mm as shown in fig. 6.
According to the technical scheme, the in-situ observation of the prefabricated cracks and the crack propagation of the ultrathin brittle material is realized, and the difficulty that the research on the fracture resistance of the ultrathin material is restricted is solved.
The features of the invention claimed and/or described in the specification may be combined, and are not limited to the combinations set forth in the claims by the recitations therein. The technical solutions obtained by combining the technical features in the claims and/or the specification also belong to the scope of the present invention.
The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention in any way, and any simple modification, equivalent change and modification made to the above embodiment according to the technical spirit of the present invention are still within the scope of the technical solution of the present invention.
Claims (12)
1. A method for prefabricating cracks on an ultrathin brittle material is characterized by comprising the following steps:
1) processing a brittle material into a sample wafer in a cuboid shape, wherein the thickness of the sample wafer is less than or equal to 1 mm;
2) pasting the sample piece on a metal matrix in a cuboid shape to obtain a complex; wherein the long edge of the sample wafer is parallel to the long edge of the metal matrix; width of the coupon < width of the metal substrate; the length of the sample wafer is less than or equal to that of the metal matrix; the bottom surface of the sample wafer is completely positioned on the top surface of the metal matrix;
3) making a notch on the long edge of one side of the sample wafer; the composite body comprises two side surfaces of a long side, wherein the side surface close to the notch is a first side surface, and the other side surface is a second side surface;
4) loading the composite body to manufacture an initial crack, and enabling the interval of the first side surface, which comprises the notch, to be in a tension area;
5) and slowly loading, and monitoring the crack image in real time until the crack reaches the target length of the prefabricated crack.
2. The method of claim 1, wherein the loading of step 4) is a four-point bend loading of the first and second sides of the composite in a horizontal direction; wherein the two force points A, B applied to the first side are located on either side of the notch, and the two force points C, D applied to the second side are located between A and B and on either side of the notch.
3. The method of claim 1, wherein the ratio of the target length of the pre-crack to the width of the coupon is 0.4-0.6.
4. The method according to claim 1, wherein the ratio of the width of the metal substrate to the width of the sample wafer is 1.2 to 1.7; the thickness of the metal substrate is 3/4 times its width.
5. The method of claim 1, wherein the notch is located at the middle of the long side of the sample, and the position fluctuation range is less than or equal to 3%.
6. The method of claim 1, wherein the notch has a dimension in the width direction of the coupon that is no greater than 0.1 times the width of the coupon.
7. The method of claim 1, wherein one long side of the swatch is located within the second side.
8. The method according to claim 1, wherein the slow loading is displacement loading, and the loading speed is 0.05-0.1 mm/min.
9. An apparatus for pre-cracking, characterized in that it comprises:
a fixing jig including a first supporting unit and a second supporting unit connected to each other; the first supporting unit is provided with a platform for placing a processed workpiece; the second supporting unit comprises two symmetrically arranged supporting parts; one side of the supporting part facing the platform is an arc surface; when a workpiece to be processed is placed on the platform, the cambered surface of the supporting part is in line contact with the workpiece to be processed in the vertical direction;
the movable pressure head is arranged on one side of the platform, can move in the horizontal direction and comprises two symmetrically arranged convex parts; one side of the convex part facing the platform is an arc surface; when a workpiece to be processed is placed on the platform, the cambered surface of the protruding part is in line contact with the workpiece to be processed in the vertical direction; the two supporting parts and the two protruding parts are respectively positioned on opposite sides of the platform and can provide four-point bending load which is in accordance with GB/T6569 for a workpiece placed on the platform;
a tool microscope including a stage and an observation mirror; and a horizontal loading device consisting of a fixed clamp and a movable pressure head is arranged on the workbench, and the crack propagation process of the processed workpiece is monitored in real time through the observation sight glass.
10. The apparatus of claim 9 wherein the movement of the movable ram comprises rotational movement in a horizontal direction and translational movement in a horizontal direction.
11. The apparatus of claim 9, wherein the arcuate surface of the protruding member and the arcuate surface of the support member are both arcuate surfaces.
12. The apparatus of claim 9, wherein the distance between two of the raised members is less than the distance between two of the support members.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010948883.4A CN112067462A (en) | 2020-09-10 | 2020-09-10 | Method and device for prefabricating cracks on ultrathin brittle material |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010948883.4A CN112067462A (en) | 2020-09-10 | 2020-09-10 | Method and device for prefabricating cracks on ultrathin brittle material |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN112067462A true CN112067462A (en) | 2020-12-11 |
Family
ID=73664702
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010948883.4A Pending CN112067462A (en) | 2020-09-10 | 2020-09-10 | Method and device for prefabricating cracks on ultrathin brittle material |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112067462A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112924254A (en) * | 2021-01-29 | 2021-06-08 | 中国建材检验认证集团股份有限公司 | Method and system for preparing transparent material natural crack and determining tip position |
| CN113607568A (en) * | 2021-07-08 | 2021-11-05 | 中国建材检验认证集团股份有限公司 | Method and device for testing fracture toughness of ceramic substrate |
| GB2605430A (en) * | 2021-03-31 | 2022-10-05 | Airbus Operations Ltd | Load-bearing structures |
| CN113607568B (en) * | 2021-07-08 | 2024-05-14 | 中国建材检验认证集团股份有限公司 | Method and device for testing fracture toughness of ceramic substrate |
Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101210866A (en) * | 2006-12-27 | 2008-07-02 | 中国科学院金属研究所 | Method for evaluating ceramic materials fracture toughness |
| CN101373173A (en) * | 2008-08-27 | 2009-02-25 | 哈尔滨工业大学 | Method and apparatus for testing brittle material strength |
| JP2011169745A (en) * | 2010-02-18 | 2011-09-01 | Ihi Corp | Method for measuring brittle crack stopping fracture toughness |
| CN107607394A (en) * | 2017-10-16 | 2018-01-19 | 武汉钢铁有限公司 | 4 angle couplings tool and its loading method for the loading of thin plate high stress |
| CN107796710A (en) * | 2017-09-21 | 2018-03-13 | 中车青岛四方机车车辆股份有限公司 | A kind of detection method of anticorrosion stress-resistant performance |
| CN107860657A (en) * | 2017-11-02 | 2018-03-30 | 沈阳航空航天大学 | A kind of method of testing of adhesive toughness |
| CN108204922A (en) * | 2017-12-30 | 2018-06-26 | 大连理工大学 | A kind of method that three-point bending standard sample crack length is determined based on strain measurement technique |
| CN110031330A (en) * | 2019-03-07 | 2019-07-19 | 航天科工防御技术研究试验中心 | A kind of test sample, preparation method and the test method of ceramic coating bond strength |
| KR20200001272U (en) * | 2018-12-07 | 2020-06-17 | 탑테크(주) | Apparatus for adding bending stress three-point and four-point |
-
2020
- 2020-09-10 CN CN202010948883.4A patent/CN112067462A/en active Pending
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101210866A (en) * | 2006-12-27 | 2008-07-02 | 中国科学院金属研究所 | Method for evaluating ceramic materials fracture toughness |
| CN101373173A (en) * | 2008-08-27 | 2009-02-25 | 哈尔滨工业大学 | Method and apparatus for testing brittle material strength |
| JP2011169745A (en) * | 2010-02-18 | 2011-09-01 | Ihi Corp | Method for measuring brittle crack stopping fracture toughness |
| CN107796710A (en) * | 2017-09-21 | 2018-03-13 | 中车青岛四方机车车辆股份有限公司 | A kind of detection method of anticorrosion stress-resistant performance |
| CN107607394A (en) * | 2017-10-16 | 2018-01-19 | 武汉钢铁有限公司 | 4 angle couplings tool and its loading method for the loading of thin plate high stress |
| CN107860657A (en) * | 2017-11-02 | 2018-03-30 | 沈阳航空航天大学 | A kind of method of testing of adhesive toughness |
| CN108204922A (en) * | 2017-12-30 | 2018-06-26 | 大连理工大学 | A kind of method that three-point bending standard sample crack length is determined based on strain measurement technique |
| KR20200001272U (en) * | 2018-12-07 | 2020-06-17 | 탑테크(주) | Apparatus for adding bending stress three-point and four-point |
| CN110031330A (en) * | 2019-03-07 | 2019-07-19 | 航天科工防御技术研究试验中心 | A kind of test sample, preparation method and the test method of ceramic coating bond strength |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112924254A (en) * | 2021-01-29 | 2021-06-08 | 中国建材检验认证集团股份有限公司 | Method and system for preparing transparent material natural crack and determining tip position |
| GB2605430A (en) * | 2021-03-31 | 2022-10-05 | Airbus Operations Ltd | Load-bearing structures |
| CN113607568A (en) * | 2021-07-08 | 2021-11-05 | 中国建材检验认证集团股份有限公司 | Method and device for testing fracture toughness of ceramic substrate |
| CN113607568B (en) * | 2021-07-08 | 2024-05-14 | 中国建材检验认证集团股份有限公司 | Method and device for testing fracture toughness of ceramic substrate |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Sharpe Jr | Applications of the interferometric strain/displacement gage | |
| Cao et al. | An experimental study of the fracture resistance of bimaterial interfaces | |
| CN106289975B (en) | Method for testing fracture toughness of material micro-area | |
| CN112067462A (en) | Method and device for prefabricating cracks on ultrathin brittle material | |
| CN112345380A (en) | Method for testing fracture toughness of ceramic coating | |
| CN112665931B (en) | High-flux statistical characterization method for metal micromechanics performance | |
| CN106092785B (en) | Using the method for asymmetric crackle test fatigue crack growth rate | |
| KR20180127095A (en) | Estimation Apparatus and Method of Creep Crack Rate and Relevant Growth Fracture Parameters for Small Punch Specimen with a Micro Groove | |
| Plaisted et al. | Compression-induced axial crack propagation in DCDC polymer samples: experiments and modeling | |
| US20230035902A1 (en) | Device and method for testing fracture toughness of solid-ice interface on surface of coating material in large-scale freezing status | |
| CN112649360B (en) | Method for testing bonding strength of silver coating | |
| CN109870258A (en) | A kind of instrumentation spherical shape indentation detection method of any residual stress of plane | |
| JP4962353B2 (en) | Cross-cut test method and cross-cut test apparatus | |
| CN110823735B (en) | Method for constructing surface hardness difference based on non-uniform stress | |
| CN110530718B (en) | Double-shaft residual stress introducing device based on white light interferometry surface morphology | |
| CN108896411B (en) | Shearing experimental device for sandwich plate core layer and experimental method thereof | |
| Mackin et al. | Fiber bundle pushout: A technique for the measurement of interfacial sliding properties | |
| Bradley | Strength testing of adhesives and consolidants for conservation purposes | |
| Duncan et al. | Measurement Good Practice Guide No. 72 | |
| CN114965054A (en) | Method for testing bending fracture mechanical property of diamond self-supporting film micro cantilever beam | |
| CN112924254B (en) | Transparent material natural crack preparation and tip position determination method and system | |
| Jankowski et al. | Combined loading and failure analysis of lead-free solder joints due to creep and fatigue phenomena | |
| CN114839039A (en) | Metal matrix composite fiber ejection test device and test method | |
| Kim | Adhesion Measurement Methods for Thin Films in Microelectronics | |
| JP2005257514A (en) | Coating film adhesion strength measuring method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |