Fatigue test clamp assembly for refractory metal and alloy thereof

Abstract

The utility model discloses a refractory metal and alloy fatigue test fixture assembly, which comprises a combined boss cushion block, a first half boss cushion block and a second half boss cushion block which are bilaterally symmetrical, and when the first half boss cushion block and the second half boss cushion block are mutually attached, the first half boss cushion block and the second half boss cushion block are attached to a clamping area of a refractory metal and alloy sample of the refractory metal; the sleeve comprises a column body, a first groove for bearing the combined boss cushion block is formed in the left end, in the axis direction, of the column body, and the groove wall of the first groove is attached to the outer side face of the combined boss cushion block; the ejector rod comprises a rod body, the left end of the rod body is detachably connected with the right end, in the axis direction, of the column body, and a connector used for being connected with a testing machine is arranged at the right end of the rod body. The clamp assembly provided by the utility model is tightly attached to the sample, and the sample is tightly ejected by the ejector rod, so that a loading system formed by the clamp assembly and the sample has better rigidity, and a zero-crossing load tension and compression fatigue test can be carried out.

Description

Technical Field

[0001] The utility model relates to the technical field of refractory metal and alloy testing, in particular to a refractory metal and alloy fatigue testing fixture component. Background Art

[0002] Refractory metals such as tungsten, rhenium, molybdenum, tantalum, niobium and their alloys have the advantages of high toughness and excellent high temperature resistance, and are widely used in aerospace, nuclear power and medical fields. As structural materials used under special conditions, the testing and evaluation of mechanical properties play an extremely important role in the development and application of refractory metals and their alloys. Accurately obtaining mechanical property data such as fatigue of refractory metals can provide a solid foundation for the design, processing and application of high-performance refractory metals and their alloys, and expand the development direction of materials.

[0003] Refractory metal and alloy specimens generally used for fatigue testing of refractory metals and their alloys, with structures such as Figure 1 As shown, it includes a clamping area 4-1 and a test area 4-2, wherein the clamping area 4-1 is a part for clamping by a fixture, and the test area 4-2 is a part for performing fatigue tests, wherein the clamping area 4-1 includes a first boss 4-1-1 and a second boss 4-1-2 arranged at the end of the test area, and a connecting rod 4-1-3 is arranged in the axial direction between the first boss 4-1-1 and the second boss 4-1-2, and the connecting rod 4-1-3 is used to connect the first boss 4-1-1 and the second boss 4-1-2, that is, the refractory metal and its alloy specimens used in the test are circular cross-sections with bosses. Since the circular cross-section has the same dimensions in all directions of the cross-section, no stress concentration will occur at the edge, and it is a more ideal specimen type for testing mechanical properties. At present, the widely used clamping methods for metal materials are threaded connection clamps and wedge clamps. The threaded connection clamp is made by processing the two ends of refractory metals and their alloys into threaded connection joints, so that the samples of refractory metals and their alloys can be clamped and fastened by threaded connection. However, due to the high hardness of refractory metals and their alloys, samples of refractory metals and their alloys are difficult to machine into threaded connection joints, and wedge clamps are prone to generate lateral extrusion stress on the refractory metals and their alloys samples at the clamping position when clamping. In severe cases, the refractory metals and their alloys samples may break. Therefore, the two existing clamps are not suitable for refractory metals and their alloys samples. Utility Model Content

[0004] The technical problem to be solved by the utility model is to provide a refractory metal and its alloy fatigue test fixture assembly in view of the deficiencies in the above-mentioned prior art, wherein the refractory metal and its alloy sample is clamped by using a combined boss pad that fits the end portion of the refractory metal and its alloy sample, and then the position of the combined boss pad is fixed by a sleeve to fit tightly with the sample. Since the push rod presses the sample tightly, the loading system composed of the fixture assembly and the sample has good rigidity, and can perform tension and compression fatigue tests with zero load.

[0005] In order to solve the above technical problems, the technical solution adopted by the utility model is: a refractory metal and alloy fatigue test fixture assembly, comprising:

[0006] The combined boss pad includes a left-right symmetrical first half boss pad and a second half boss pad, wherein the first half boss pad and the second half boss pad are in contact with each other and in contact with the clamping area of ​​the refractory metal and its alloy sample;

[0007] The sleeve comprises a column, wherein the left end of the column along the axial direction is provided with a first groove for carrying the combined boss pad, and the groove wall of the first groove is in contact with the outer side surface of the combined boss pad;

[0008] The push rod comprises a rod body, the left end of the rod body is detachably connected to the right end of the column body along the axial direction, and the right end of the rod body is provided with a connecting head for connecting to a testing machine.

[0009] Furthermore, a second groove is formed at the right end of the column along the axial direction, and a groove wall of the second groove fits with the rod surface of the rod body.

[0010] Furthermore, it is characterized in that the groove wall of the second groove is provided with an internal thread, and the rod surface at the left end of the rod body is provided with an external thread matching the internal thread.

[0011] Furthermore, a depression is arranged at the bottom of the second groove, and a protrusion matching the depression is arranged at the top of the left end of the rod body.

[0012] Furthermore, a cut surface groove for holding the rod is provided on the rod surface of the rod body.

[0013] Furthermore, the first half-boss pad and the second half-boss pad are detachably connected.

[0014] Furthermore, the groove wall of the first groove is detachably connected to the outer side surface of the combined boss pad.

[0015] Furthermore, the first semi-boss pad includes two semi-cylindrical shells with different cross-sectional radii, and the semi-cylindrical shells are semi-cylindrical shells separated along the section where the cylindrical axis is located, wherein the outer side surface of the semi-cylindrical shell with a larger cross-sectional radius is fitted with the first groove, the inner side surface of the semi-cylindrical shell with a larger cross-sectional radius is fitted with the second boss of the refractory metal and its alloy sample, and the inner side surface of the semi-cylindrical shell with a smaller cross-sectional radius is fitted with the connecting rod of the refractory metal and its alloy sample.

[0016] Compared with the prior art, the utility model has the following advantages:

[0017] The utility model provides a refractory metal and its alloy fatigue test fixture component, which clamps the refractory metal and its alloy sample by using a combined boss pad that fits the end of the refractory metal and its alloy sample, and then fixes the position of the combined boss pad by a sleeve, so that the fixture component is tightly fitted to the sample. Since a push rod presses the sample tightly, a loading system composed of the fixture component and the sample has good rigidity, and can perform a tensile and compressive fatigue test with zero load. During the test, no lateral extrusion stress is generated when clamping, and there is no need to process threads on the end of the refractory metal and its alloy sample. The utility model is suitable for clamping the refractory metal and its alloy sample. Compared with the clamping method of a traditional wedge-shaped clamp, the clamping part will not be subjected to a large lateral extrusion stress, and no fracture will occur at the clamping position. When the refractory metal and its alloy sample is subjected to load, the fixture and the sample will not slide relative to each other, and the measurement of the sample strain is more accurate.

[0018] The technical solution of the utility model is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the structure of refractory metal and alloy specimens currently used in fatigue tests of refractory metals and alloys.

[0020] Figure 2 The utility model provides a schematic diagram of the overall structure of a refractory metal and alloy fatigue test fixture assembly.

[0021] Figure 3 It is a structural schematic diagram of the combined boss pad in the utility model.

[0022] Figure 4 It is a structural schematic diagram of the sleeve in the utility model.

[0023] Figure 5 It is a structural schematic diagram of the push rod in the utility model.

[0024] Description of reference numerals:

[0025] 1. Combined boss block; 1-1. First half boss block; 1-2. Second half boss block; 2. Sleeve; 2-1. Cylinder; 2-2. Internal thread; 2-3. Second groove; 2-4. First groove; 3. Push rod; 3-1. Connector; 3-2. Rod body; 3-3. External thread; 4. Refractory metal and alloy specimens; 4-1. Clamping area; 4-1-1. First boss; 4-1-2. Second boss; 4-1-3. Connecting rod; 4-2. Test area. DETAILED DESCRIPTION

[0026] like Figure 2-5 As shown, the utility model provides a refractory metal and alloy fatigue test fixture assembly, comprising: a combined boss pad 1, a sleeve 2 and a push rod 3.

[0027] The combined boss pad 1 comprises a left-right symmetrical first half boss pad 1-1 and a second half boss pad 1-2, wherein the first half boss pad 1-1 and the second half boss pad 1-2 are bonded to a clamping area 4-1 of a refractory metal or alloy sample 4 when bonded to each other;

[0028] The sleeve 2 comprises a column 2-1, wherein the left end of the column 2-1 along the axial direction is provided with a first groove 2-4 for carrying the combined boss pad 1, and the groove wall of the first groove 2-4 is in contact with the outer side surface of the combined boss pad 1;

[0029] The top rod 3 includes a rod body 3-2, the left end of the rod body 3-2 is detachably connected to the right end of the column 2-1 along the axial direction, and the right end of the rod body 3-2 is provided with a connector 3-1 for connecting to a testing machine.

[0030] When used, the refractory metal and its alloy fatigue test uses refractory metal and its alloy specimens 4 such as Figure 1 As shown, the combined boss pad 1 is used to clamp the end of the refractory metal and its alloy sample 4, so that the small cylindrical part of the combined boss pad 1 is firmly stuck between the two bosses at the end of the refractory metal and its alloy sample 4, and the size is just right. The large cylindrical part of the combined boss pad 1 fits with the outermost end of the refractory metal and its alloy sample 4. When the combined boss pad 1 is put on the refractory metal and its alloy sample 4, the combined boss pad 1 is opened, and the refractory metal and its alloy sample 4 is placed between the first half boss pad 1-1 and the second half boss pad 1-2, and then the first half boss pad 1-1 and the second half boss pad 1-2 are buckled together. At this time, the combined boss pad 1 and the refractory metal and its alloy sample 4 fit together.

[0031] Afterwards, use the sleeve 2 to place the large cylindrical part of the combined boss pad 1 into the first groove 2-4. At this time, the relative position between the first half boss pad 1-1 and the second half boss pad 1-2 will not change. At this time, install the sleeve 2 on the rod body 3-2 of the push rod 3, and then start the fatigue test.

[0032] like Figure 2 As shown, the first half-boss pad 1-1 includes two semi-cylindrical shells with different cross-sectional radii, and the semi-cylindrical shells are semi-cylindrical shells separated along the section where the cylindrical axis is located, wherein the outer side surface of the semi-cylindrical shell with a larger cross-sectional radius fits with the first groove 2-4, so that the combined boss pad 1 and the refractory metal and its alloy sample 4 fit tightly, and pray for uniform force during the test. The second half-boss pad 1-2 has the same structure as the first half-boss pad 1-1, and the inner side surface of the semi-cylindrical shell with a larger cross-sectional radius fits with the second boss 4-1-2 of the refractory metal and its alloy sample 4, and the inner side surface of the semi-cylindrical shell with a smaller cross-sectional radius fits with the connecting rod 4-1-3 of the refractory metal and its alloy sample 4.

[0033] like Figure 3 As shown, the right end of the column 2-1 along the axial direction is also provided with a second groove 2-3, and the groove wall of the second groove 2-3 fits with the rod surface of the rod body 3-2, so that the rod body 3-2 is embedded in the column 2-1, increasing the firmness of the clamp and improving the stability during the test.

[0034] In order to achieve better results, Figure 4 As shown, the connection between the column 2-1 and the rod 3-2 is more tightly secured, an internal thread 2-2 is provided on the groove wall of the second groove 2-3, and an external thread 3-3 matching the internal thread 2-2 is provided on the rod surface at the left end of the rod 3-2. On this basis, a depression can be provided at the bottom of the second groove 2-3, and a protrusion matching the depression can be provided on the top of the left end of the rod 3-2.

[0035] In order to improve the convenience of use, the utility model is provided with a cut surface groove for hand holding on the rod surface of the rod body 3-2.

[0036] In the present invention, the first half boss pad 1-1 is detachably connected to the second half boss pad 1-2. The groove wall of the first groove 2-4 is detachably connected to the outer side surface of the combined boss pad 1.

[0037] The clamp assembly provided by the utility model fits tightly with the refractory metal and its alloy sample. Since the push rod presses the sample tightly, the loading system composed of the clamp assembly and the sample has good rigidity, and can carry out tension and compression fatigue tests with zero load. The clamp assembly and the refractory metal and its alloy sample are in contact with each other through a cylindrical surface and two annular surfaces, and when subjected to tensile and compressive loads, the sample boss and the end will not shear and fracture. Compared with the clamping method of the traditional wedge clamp, the clamping part will not be subjected to a large lateral extrusion stress, and the clamping part will not fracture. When the refractory metal and its alloy sample is tested, no relative sliding will occur between the clamp and the refractory metal and its alloy sample when subjected to load, so that the strain measurement of the refractory metal and its alloy sample is more accurate.

[0038] The material of the fixture assembly provided by the utility model is nickel-based alloy, molybdenum alloy and tungsten alloy, etc., and ultra-high temperature ceramic material can be selected under ultra-high temperature conditions. Under ultra-high temperature conditions, it has good shear resistance and creep resistance, certain strength, thermal shock resistance and hardness matching the test material, and has the advantages of no or little reaction with the test material and mutual diffusion. The fixture assembly provided by the utility model can be used for room temperature and high temperature tests and is suitable for tensile tests.

[0039] The above is only a preferred embodiment of the present invention and does not constitute any limitation to the present invention. Any simple modification, change and equivalent structural change made to the above embodiments according to the technical essence of the present invention shall still fall within the protection scope of the technical solution of the present invention.

Claims

1. A refractory metal and alloy fatigue test fixture assembly, It is characterized in that include: A combined boss pad (1) comprises a left-right symmetrical first half boss pad (1-1) and a second half boss pad (1-2), wherein the first half boss pad (1-1) and the second half boss pad (1-2) are in contact with each other and in contact with a clamping area (4-1) of a refractory metal or alloy sample (4); The sleeve (2) comprises a column (2-1), wherein the left end of the column (2-1) along the axial direction is provided with a first groove (2-4) for carrying the combined boss pad (1), and the groove wall of the first groove (2-4) is in contact with the outer side surface of the combined boss pad (1); The push rod (3) comprises a rod body (3-2), the left end of the rod body (3-2) being detachably connected to the right end of the column body (2-1) along the axial direction, and the right end of the rod body (3-2) being provided with a connecting head (3-1) for connecting to a testing machine.

2. A refractory metal and alloy fatigue test fixture assembly according to claim 1, It is characterized in that A second groove (2-3) is also provided at the right end of the column (2-1) along the axial direction, and the groove wall of the second groove (2-3) is in contact with the rod surface of the rod body (3-2).

3. A refractory metal and alloy fatigue test fixture assembly according to claim 2, It is characterized in that An internal thread (2-2) is arranged on the groove wall of the second groove (2-3), and an external thread (3-3) matching the internal thread (2-2) is arranged on the rod surface at the left end of the rod body (3-2).

4. A refractory metal and alloy fatigue test fixture assembly according to claim 3, It is characterized in that The bottom of the second groove (2-3) is provided with a depression, and the top of the left end of the rod body (3-2) is provided with a protrusion matching the depression.

5. A refractory metal and alloy fatigue test fixture assembly according to claim 1, It is characterized in that The rod surface of the rod body (3-2) is provided with a cut surface groove for hand holding.

6. A refractory metal and alloy fatigue test fixture assembly according to claim 1, It is characterized in that The first half-boss pad (1-1) and the second half-boss pad (1-2) are detachably connected.

7. A refractory metal and alloy fatigue test fixture assembly according to claim 1, It is characterized in that The groove wall of the first groove (2-4) is detachably connected to the outer side surface of the combined boss pad (1).

8. A refractory metal and alloy fatigue test fixture assembly according to claim 1, It is characterized in that The first semi-boss pad (1-1) comprises two semi-cylindrical shells with different cross-sectional radii, wherein the semi-cylindrical shells are separated along the section where the cylindrical axis is located, wherein the outer side surface of the semi-cylindrical shell with a larger cross-sectional radius fits with the first groove (2-4), the inner side surface of the semi-cylindrical shell with a larger cross-sectional radius fits with the second boss (4-1-2) of the refractory metal and its alloy sample (4), and the inner side surface of the semi-cylindrical shell with a smaller cross-sectional radius fits with the connecting rod (4-1-3) of the refractory metal and its alloy sample (4).

Images