Elastic limit strength testing method for tungsten / molybdenum wire

Abstract

The present invention relates to the technical field of tungsten / molybdenum materials, and in particular relates to an elastic limit strength testing method for tungsten / molybdenum wire. Specifically, the method comprises: cutting a tungsten / molybdenum wire test piece; using a tensile testing machine to clamp both ends of the test piece and applying a load for testing; measuring the diameter of the test piece and calculating the stress, where stress = the tensile force applied by the tensile testing machine / the cross-sectional area of the test piece; plotting a stress-strain curve; in a diagram of the stress-strain curve, drawing, from the point at which the abscissa strain is 0.2%, a straight line approximately parallel to a front section of the curve, the intersection point between the straight line and the curve being the elastic limit strength. The elastic limit strength testing method for tungsten / molybdenum wire provided by the present invention is suitable for tungsten / molybdenum wires having diameters of 5-500 μm. The testing method is simple and easy to operate, the measured data is stable and reliable, and can truly reflect the performance characteristics of a material, thereby meeting the testing needs of research and development and production.

Description

A method for testing the elastic limit strength of tungsten / molybdenum wire Technical Field

[0001] The present invention relates to the technical field of tungsten / molybdenum materials, and in particular to a method for testing the elastic limit strength of tungsten / molybdenum wires. Background Art

[0002] Tungsten / molybdenum wire features high strength, electrical corrosion resistance, low elongation, and excellent discharge performance. This ensures machining stability and dimensional accuracy of the workpiece, and is suitable for precision cutting of complex components. Therefore, it is widely used in fields such as electronic and electrical equipment, metal processing, glass manufacturing, and the aerospace and defense industries. When tungsten / molybdenum wire is used in silicon wafer cutting, its elastic limit strength reflects its ability to maintain elasticity after being subjected to stress. The greater the elastic limit strength, the less deformation and damage to the silicon wafer surface during cutting, and the better the quality of the resulting silicon wafer. Existing methods for measuring the elastic limit of metal materials use tensile testing to obtain a stress-strain curve. As shown in Figure 1, during the tensile process, as the loading force increases, the metal material undergoes elastic deformation, yielding, plastic deformation, and fracture in sequence, with point A representing the elastic limit strength of the material. However, due to the high strength and high elastic modulus of tungsten / molybdenum materials, there is no yielding after elastic deformation, making the elastic limit difficult to identify. Therefore, it is necessary to design a method for testing the elastic limit strength of tungsten / molybdenum wire.

[0003] Summary of the Invention

[0004] In order to solve the problem that the existing technology is not suitable for testing the elastic limit strength of tungsten / molybdenum wires, the present invention provides a method for testing the elastic limit strength of tungsten / molybdenum wires.

[0005] The present invention provides a method for testing the elastic limit strength of a tungsten / molybdenum wire. A tungsten / molybdenum wire specimen is cut, two ends of the specimen are clamped by a tensile testing machine, and a load test is performed to obtain a stress-strain curve. The diameter of the specimen is measured. In the stress-strain curve, a straight line that is substantially parallel to the front section of the curve is drawn from a position where the abscissa strain is 0.2%, and the intersection of the straight line and the curve is the elastic limit strength.

[0006] It is understood that a tensile testing machine is a common tensile testing device, also known as a tensile testing machine. In the present invention, the tensile testing machine uses beam displacement to record deformation, with a beam displacement detection accuracy of 0.01mm. Loading and unloading during the experiment are automatically controlled by a program, and experimental data is automatically collected in real time to obtain reliable stress-strain curves. Furthermore, the horizontal and vertical coordinates of the obtained stress-strain curves should start from zero to ensure accurate testing.

[0007] Furthermore, sandpaper is attached to the chuck where it contacts the test piece. Because tungsten / molybdenum wire is relatively thin, direct clamping with the chuck can easily cause it to slip, leading to test failure. Therefore, attaching sandpaper to the chuck increases friction between the chuck and the tungsten / molybdenum wire and facilitates easy replacement of the sandpaper if it breaks or loses grit.

[0008] Furthermore, when the diameter of the test piece is 100-500 μm, the mesh number of the sandpaper is 240-400 mesh, and the particle size of the sandpaper is 38-62 μm;

[0009] When the diameter of the test piece is 50-100 μm, the mesh number of the sandpaper is 400-1000 mesh, and the particle size of the sandpaper is 14-38 μm;

[0010] When the diameter of the test piece is 5-50 μm, the mesh number of the sandpaper is 1000-3000 mesh, and the particle size of the sandpaper is 4.5-14 μm.

[0011] Furthermore, the test piece is 300mm long, with a 200mm measuring section and 50mm of clamping space at each end. Due to the influence of the wire diameter, if the sandpaper does not match the wire diameter, for example, using too fine sandpaper to clamp a thick diameter wire, or too coarse sandpaper to clamp a thin diameter wire, it will not increase friction, causing the test process to slip and fail. Moreover, using too coarse sandpaper for clamping can easily damage the wire, causing it to break at the damaged location during testing, resulting in inaccurate test results. Therefore, it is necessary to use sandpaper with different mesh sizes and grits for wires of different diameters.

[0012] Furthermore, when the specimen diameter is 50-500 μm, the tensile testing machine test speed is 60-90 mm / min;

[0013] When the specimen diameter is 5-50 μm, the tensile testing machine's test speed is 30-60 mm / min. The tensile testing machine's test speed affects efficiency. Conventional tensile testing uses a test speed of 10-30 mm / min, which is inefficient. Therefore, a test speed of 30-90 mm / min is used to improve measurement efficiency. Furthermore, when the wire diameter is small, the test speed should be appropriately slowed to prevent breakage.

[0014] Furthermore, the specimen diameter was measured using a laser caliper. The diameter of the test piece is a key parameter in calculating the elastic limit strength. Because the diameter of the tungsten / molybdenum wire being measured is extremely fine, weight conversion is typically used, which can differ from the actual diameter. Using a laser caliper to measure the diameter provides a more accurate diameter, leading to a more accurate calculation of the elastic limit strength.

[0015] Compared with the existing technology, the elastic limit strength test method of tungsten / molybdenum wire provided by the present invention is applicable to tungsten / molybdenum wire with a diameter of 5-500μm. The test method is simple and easy to operate, the measurement data is stable and reliable, and it can truly reflect the performance characteristics of the material, thereby meeting the testing needs of research and development and production. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 is a stress-strain curve diagram of common metal materials;

[0018] FIG2 is a stress-strain curve diagram of a tungsten / molybdenum wire provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0020] The present invention provides a method for testing the elastic limit strength of a tungsten / molybdenum wire. Specifically, the method comprises the following steps: cutting a tungsten / molybdenum wire specimen, clamping both ends of the specimen using a tensile testing machine and performing a load test to obtain a stress-strain curve, measuring the diameter of the specimen, and drawing a straight line substantially parallel to the front section of the curve from a position where the abscissa strain is 0.2% in the stress-strain curve. The intersection of the straight line and the curve represents the elastic limit strength.

[0021] Sandpaper is pasted on the position where the clamping chuck of the tensile testing machine contacts the test piece.

[0022] Wherein, when the diameter of the test piece is 100-500 μm, the mesh number of the sandpaper is 240-400 mesh, and the particle size of the sandpaper is 38-62 μm;

[0023] When the diameter of the test piece is 50-100 μm, the mesh number of the sandpaper is 400-1000 mesh, and the particle size of the sandpaper is 14-38 μm;

[0024] When the diameter of the test piece is 5-50 μm, the mesh number of the sandpaper is 1000-3000 mesh, and the particle size of the sandpaper is 4.5-14 μm.

[0025] The length of the test piece is 300 mm, of which the measuring section is 200 mm long, and 50 mm is left at each end for clamping.

[0026] When the specimen diameter is 50-500 μm, the tensile testing machine test speed is 60-90 mm / min;

[0027] When the diameter of the test piece is 5-50 μm, the testing speed of the tensile testing machine is 30-60 mm / min.

[0028] The diameter of the test piece is measured by a laser caliper.

[0029] Example 1

[0030] A tungsten wire with a length of 300 mm and a diameter of 33 μm was cut as a specimen, of which the measuring section was 200 mm long, leaving 50 mm at each end for clamping. A tensile testing machine was used to clamp both ends of the specimen and load the test. After the specimen diameter was measured using a laser caliper, the stress was calculated (stress = tensile force loaded by the tensile testing machine / cross-sectional area of ​​the specimen). The stress-strain curve was drawn. In the stress-strain curve, a straight line was drawn from the point where the strain on the horizontal axis was 0.2% and was nearly parallel to the front section of the curve. The intersection of the straight line and the curve was the elastic limit strength.

[0031] Among them, the position where the clamping chuck of the tensile testing machine contacts the specimen is affixed with 2000-mesh sandpaper with a sandpaper particle size of 8 μm; the testing speed of the tensile testing machine is 40 mm / min.

[0032] The above test operation was repeated 5 times to obtain 5 sets of elastic limit strength data, which were 2343 MPa, 2342 MPa, 2342 MPa, 2343 MPa, and 2346 MPa, respectively. The differences between the 5 sets of data were small, indicating that the elastic limit strength test method for tungsten / molybdenum wire provided by the present invention can measure data stably and reliably.

[0033] Example 2

[0034] A tungsten wire with a length of 300 mm and a diameter of 58 μm was taken as a specimen, wherein the measuring section was 200 mm long, and 50 mm was left at each end for clamping. A tensile testing machine was used to clamp both ends of the specimen and load the test. After the diameter of the specimen was measured with a laser caliper, the stress was calculated. Stress = tensile force loaded by the tensile testing machine / cross-sectional area of ​​the specimen. The stress-strain curve was drawn. In the stress-strain curve, a straight line was drawn from the point where the strain on the horizontal axis was 0.2% and was nearly parallel to the front section of the curve. The intersection of the straight line and the curve was the elastic limit strength.

[0035] Among them, the position where the clamping chuck of the tensile testing machine contacts the specimen is affixed with 1000-mesh sandpaper with a sandpaper particle size of 10 μm; the testing speed of the tensile testing machine is 60 mm / min.

[0036] The above test operation was repeated 5 times to obtain 5 sets of elastic limit strength data, which were 2148 MPa, 2149 MPa, 2148 MPa, 2150 MPa, and 2148 MPa, respectively. The difference between the 5 sets of data was small, which shows that the elastic limit strength test method of tungsten / molybdenum wire provided by the present invention can measure data stably and reliably.

[0037] Example 3

[0038] A molybdenum wire with a length of 300 mm and a diameter of 500 μm was cut as a specimen, where the measuring section was 200 mm long and 50 mm was left at each end for clamping. A tensile testing machine was used to clamp both ends of the specimen and load the test. After the specimen diameter was measured using a laser diameter gauge, the stress was calculated. Stress = tensile force loaded by the tensile testing machine / cross-sectional area of ​​the specimen. The stress-strain curve was drawn. In the stress-strain curve, a straight line was drawn from the point where the strain on the horizontal axis was 0.2% that was nearly parallel to the front section of the curve. The intersection of the straight line and the curve was the elastic limit strength.

[0039] Among them, the position where the clamping chuck of the tensile testing machine contacts the specimen is affixed with 400-mesh sandpaper with a sandpaper particle size of 62 μm; the test speed of the tensile testing machine is 90 mm / min.

[0040] The above test operation was repeated 5 times to obtain 5 sets of elastic limit strength data, which were 1224 MPa, 1228 MPa, 1225 MPa, 1224 MPa, and 1226 MPa, respectively. The differences between the 5 sets of data were small, indicating that the elastic limit strength test method for tungsten / molybdenum wire provided by the present invention can measure data stably and reliably.

[0041] Comparative Example 1

[0042] The difference from Example 1 is that the sandpaper on the chuck of the tensile testing machine is 600 mesh, and the rest of the operation is the same as Example 1. Due to the low mesh number of the sandpaper, the chuck slipped when the tensile testing machine was loaded, and the specimen could not be stably clamped, so the elastic limit strength could not be measured.

[0043] Comparative Example 2

[0044] The difference from Example 1 is that the test speed of the tensile testing machine is 80 mm / min, and the other operations are the same as Example 1.

[0045] The above test operation was repeated 5 times, and 5 sets of elastic limit strength data were obtained, which were 2342MPa, 2218MPa, 2105MPa, 2089MPa, and 2325MPa respectively. It can be seen that due to the high test speed, the elastic limit strength value is unstable and has large fluctuations.

[0046] Comparative Example 3

[0047] The difference from Example 1 is that a tungsten wire with a length of 400 mm and a diameter of 33 μm is cut as a test piece, wherein the measuring section is 300 mm long, and a length of 50 mm is left at each end for clamping. The rest of the operations are the same as in Example 1.

[0048] The above test operation was repeated 5 times, and 5 sets of elastic limit strength data were obtained, which were 2345MPa, 2342MPa, 2127MPa, 2348MPa, and 1779MPa respectively. It can be seen that due to the long test length, this thin-gauge wire is easy to bend, resulting in unstable tensile force value, and the elastic limit strength value is unstable and has large fluctuations.

[0049] In summary, the elastic limit strength test method for tungsten / molybdenum wire provided by the present invention is applicable to tungsten / molybdenum wire with a diameter of 5-500 μm. The test method is simple and easy to operate, and the measurement data is stable and reliable. It can truly reflect the performance characteristics of the material, thereby meeting the testing needs of research and development and production.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for testing the elastic limit strength of tungsten / molybdenum wire materials, characterized in that: A tungsten / molybdenum wire specimen is intercepted. The two ends of the specimen are clamped and loaded for testing by a tensile testing machine. The diameter of the specimen is measured and the stress is calculated. Stress = the tensile force loaded by the tensile testing machine / the cross-sectional area of the specimen. A stress-strain curve is plotted. In the stress-strain curve graph, a straight line approximately parallel to the front section of the curve is drawn from the point where the abscissa strain is 0.2%. The intersection point of the straight line and the curve is the elastic limit strength.

2. The method for testing the elastic limit strength of tungsten / molybdenum wire according to claim 1, characterized in that: Sandpaper is pasted at the position where the chuck of the tensile testing machine for clamping contacts the specimen.

3. The method for testing the elastic limit strength of tungsten / molybdenum wire according to claim 2, wherein: When the diameter of the specimen is 100 - 500 μm, the grit number of the sandpaper is 240 - 400, and the particle size of the sandpaper is 38 - 62 μm; When the diameter of the specimen is 50 - 100 μm, the grit number of the sandpaper is 400 - 1000, and the particle size of the sandpaper is 14 - 38 μm; When the diameter of the specimen is 5 - 50 μm, the grit number of the sandpaper is 1000 - 3000, and the particle size of the sandpaper is 4.5 - 14 μm.

4. The method for testing the elastic limit strength of tungsten / molybdenum wire according to claim 1, characterized in that: The length of the specimen is 300 mm, where the length of the measurement section is 200 mm, and 50 mm is left at each end for clamping.

5. The method for testing the elastic limit strength of tungsten / molybdenum wire according to claim 1, wherein: When the diameter of the specimen is 50 - 500 μm, the testing speed of the tensile testing machine is 60 - 90 mm / min; When the diameter of the specimen is 5 - 50 μm, the testing speed of the tensile testing machine is 30 - 60 mm / min.

6. The method for testing the elastic limit strength of tungsten / molybdenum wire according to claim 1, wherein: The diameter of the specimen is measured by a laser diameter gauge.

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