A cladding type tensile specimen structure with a shoulder belt notch

Abstract

The present invention belongs to the technical field of material property testing, and particularly relates to a cladding type tensile specimen structure with a notched shoulder strap. The present invention includes a tensile specimen with a notched shoulder strap and a cladding shell. The cladding shell closes and wraps around the outside of the tensile specimen with a notched shoulder strap. The cladding shell is fixed by the upper inner mouth protrusion that catches the upper shoulder of the tensile specimen with a notched shoulder strap. The present invention utilizes the capillary action of liquid metal to make it remain in the gap between the specimen and the cladding, ensuring that the specimen is always in an environment infiltrated by liquid metal during the off-position tensile process, and solving the problem in the prior art that the embrittlement degree of materials cannot be conveniently and accurately evaluated.

Description

Technical Field

[0001] The present invention belongs to the technical field of material property testing, and particularly relates to a cladding type tensile specimen structure with a notched shoulder strap. Background Art

[0002] A tensile test refers to a test method for testing the properties of materials under axial tensile loads, which is one of the basic methods for testing the mechanical properties of materials and is mainly used to test whether the materials meet the specified standards and study the properties of the materials.

[0003] The phenomenon that the plastic toughness of metal materials decreases and even cracks under the infiltration of liquid metal is called liquid metal embrittlement (LME). Due to the limitations of conditions such as sealing, long-term load holding, and high temperature, it is difficult for existing research methods to achieve the conditions of long-term infiltration and direct tensile testing in liquid metal after loading. Currently, ordinary tensile specimens are usually taken out after soaking in liquid metal for a sufficient time (thousands of hours), and then the plastic toughness of the materials is measured off-site on a high-temperature vacuum tensile testing machine to study the degree of liquid metal embrittlement of the materials.

[0004] Under the above test conditions, the liquid metal has separated from the tensile specimen during the tensile test. Research on liquid metal embrittlement shows that whether the material can continuously contact the liquid metal during the tensile fracture process and whether the liquid metal is continuously supplied after the crack origin will seriously affect the test results. Therefore, in order to more accurately evaluate the LME behavior of materials in a liquid metal environment, a specimen structure needs to be designed so that the specimen is always in an environment infiltrated by liquid metal during off-site tensile testing. Summary of the Invention

[0005] The technical problem to be solved by the present invention is: in view of the above technical status quo, a cladding type tensile specimen structure with a notched shoulder strap for liquid metal embrittlement research is provided to ensure that the specimen is always in an environment infiltrated by liquid metal during off-site tensile testing and solve the problem that the existing technology cannot accurately evaluate the degree of material embrittlement.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0007] A cladding type tensile specimen structure with a notched shoulder strap includes a tensile specimen with a notched shoulder strap and a cladding shell. The cladding shell closes and wraps around the outside of the tensile specimen with a notched shoulder strap, and the cladding shell fixes the cladding shell by clamping the upper shoulder of the tensile specimen with a notched shoulder strap through the raised inner opening at the upper end.

[0008] The tensile specimen with notches on the shoulders includes connecting threads, upper transition sections, lower transition sections, parallel sections, upper shoulders, and lower shoulders. There is a connecting thread at each of the upper and lower ends of the tensile specimen with notches on the shoulders. The upper transition section is between the connecting thread at the upper end and the upper shoulder, and the lower transition section is between the connecting thread at the lower end and the lower shoulder. The parallel section is between the upper shoulder and the lower shoulder. All parts are transitioned by arc-shaped fillets.

[0009] The connecting threads are standard coarse pitch threads and are used to connect to a material testing machine for tensile testing.

[0010] The diameters of the upper transition section and the lower transition section are larger than the diameter of the parallel section, ensuring that the upper transition section and the lower transition section do not yield during the tensile process of the parallel section.

[0011] There are 6 longitudinal notches on the upper shoulder and the lower shoulder, and the 6 longitudinal notches are evenly distributed along the circumference.

[0012] The cladding shell is a two-piece closing shell. The inner diameter of the shell is slightly larger than the outer diameter of the shoulder. The inner opening at the upper end of the cladding shell is processed with a protrusion inward, and the inner diameter of the protrusion is slightly smaller than the outer diameter of the upper shoulder. A longitudinal notch is processed at the side opening of the cladding shell. After the cladding shell is closed, the upper end forms a funnel-shaped container. The length of the cladding shell should be sufficient to cover the total length of the parallel section during the tensile process.

[0013] The length of the upper transition section ensures that the connecting thread at the upper end is exposed from the funnel-shaped container, and the length dimension of the lower transition section ensures that the cladding shell has sufficient installation length.

[0014] There is a gap between the cladding shell and the parallel section. The liquid metal enters the gap between the parallel section of the tensile specimen and the cladding shell through the longitudinal notches on the upper shoulder and the lower shoulder and the longitudinal notch on the side of the cladding shell.

[0015] After the tensile specimen with notches on the shoulders and the cladding shell are taken out of the liquid metal, the liquid metal remains in the gap between the parallel section and the cladding shell through capillary action and solidifies after cooling.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] (1) The present invention provides a cladding-type tensile specimen structure with notches on the shoulders, which can solve the problem that in the existing research, there is no liquid metal participation during the high-temperature tensile test, and the lack of continuous action of the liquid metal during the tensile fracture process of the material will seriously affect the test results.

[0018] (2) The present invention provides a sheathed tensile specimen structure with notches on the shoulders. By adding a sheath to the tensile specimen, when infiltrating, the liquid metal enters the sheath through the longitudinal notches on the sheath and the longitudinal notches on the specimen shoulders and contacts the parallel section of the specimen, and can flow. When the specimen is separated from the liquid metal, part of the liquid metal remains in the gap between the specimen and the sheath under capillary action. After cooling to room temperature, it is solidified and taken out for high-temperature vacuum tensile testing. During the high-temperature tensile process, the solid metal placed in the funnel-shaped container at the upper end of the sheath melts and enters the gap through the upper shoulder notch to replenish the liquid metal, ensuring that the parallel section of the specimen is under the action of the liquid metal during the tensile process, and can more conveniently and accurately evaluate the LME behavior of the material under liquid metal conditions;

[0019] (3) The present invention provides a sheathed tensile specimen structure with notches on the shoulders. The sheath housing fixes the sheath by clamping the upper shoulder of the specimen with the inner mouth protrusion at the upper end. The inner diameter of the housing is slightly larger than the outer diameter of the shoulder. During the tensile process, the housing only clamps on the specimen shoulder through the inner mouth protrusion, and will not affect the tensile test results, and the test results are accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic structural diagram of the sheathed tensile specimen with notches on the shoulders in the present invention;

[0021] Figure 2 is the tensile specimen with notches on the shoulders in the present invention;

[0022] Figure 3 is the sheath housing in the present invention;

[0023] In the figure: 1 - tensile specimen with notches on the shoulders; 2 - sheath housing; 11 - connecting thread; 12 - upper transition section; 13 - lower transition section; 14 - parallel section; 15 - upper shoulder; 16 - lower shoulder; 21 - inner mouth protrusion; 22 - funnel-shaped container; 23 - longitudinal notch. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] The present invention will be further described in detail below with reference to the embodiments of the drawings.

[0025] As Figure 1 shown, a sheathed tensile specimen structure with notches on the shoulders provided by the present invention includes a tensile specimen 1 with notches on the shoulders and a sheath housing 2. The sheath housing 2 closes and wraps around the outside of the tensile specimen 1 with notches on the shoulders. The sheath housing 2 fixes the sheath by clamping the upper shoulder of the tensile specimen 1 with notches on the shoulders with the inner mouth protrusion 21 at the upper end, and fixes the sheath housing 2 with a standard clamp.

[0026] As Figure 2As shown, the tensile specimen 1 with shoulders and notches includes connecting threads 11, upper transition section 12, lower transition section 13, parallel section 14, upper shoulder 15, and lower shoulder 16.

[0027] At each of the upper and lower ends of the tensile specimen 1 with shoulders and notches, there is a connecting thread 11. Between the connecting thread 11 at the upper end and the upper shoulder 15 is the upper transition section 12, and between the connecting thread 11 at the lower end and the lower shoulder 16 is the lower transition section 13. Between the upper shoulder 15 and the lower shoulder 16 is the parallel section 14. All parts are transitioned by arc chamfers.

[0028] The connecting thread 11 is a standard coarse thread, used to connect to a material testing machine for tensile testing.

[0029] Assume that the yield strength of the specimen material at the test temperature is 80% of the tensile strength. When the diameters of the upper transition section 12 and the lower transition section 13 are greater than 1.12 times the diameter of the parallel section 14, the upper transition section 12 and the lower transition section 13 will not yield when the parallel section 14 reaches the tensile strength. Therefore, the diameters of the upper transition section 12 and the lower transition section 13 are designed to be 1.25 times the diameter of the parallel section 14.

[0030] Six longitudinal notches are opened on the upper shoulder 15 and the lower shoulder 16. The six longitudinal notches are evenly distributed along the circumference. The shape of the notch is semi-circular, and the depth is up to the surface of the upper transition section 12 or the lower transition section 13 at most.

[0031] The length of the parallel section 14 is 6 times the diameter.

[0032] As Figure 3 As shown, the cladding shell 2 is a two-piece closed shell. The inner diameter of the shell is slightly larger than the outer diameters of the upper shoulder 15 and the lower shoulder 16, so as to achieve a clearance fit when assembling with the tensile specimen. An inward bulge is machined at the inner opening at the upper end of the cladding shell 2. The inner diameter of the bulge is slightly smaller than the outer diameter of the upper shoulder 15, and it can just hold the cladding without falling off, so as to prevent the shoulder notch from being exposed too small and affecting the flow of liquid metal. A longitudinal notch 23 is machined at the side opening of the cladding shell 2. The notch is located at the opening of the shell, which is convenient for the flow of liquid metal, and the liquid metal flow during infiltration continuously acts on the specimen. After the cladding shell 2 is closed, the upper end forms a funnel-shaped container 22. The size of the funnel depends on the amount of liquid metal to be supplemented. The length of the cladding shell 2 should be sufficient to cover the total length of the parallel section 14 during the tensile process.

[0033] The length of the upper transition section 12 should be sufficient to ensure that the connecting thread 11 at the upper end is exposed outside the funnel-shaped container 22, which is convenient for installing the specimen during tensile testing. The length dimension of the lower transition section 13 should be sufficient to ensure that the cladding shell 2 has enough installation length, so that the parallel section is under the action conditions of liquid metal during the processes of elastic elongation, yield, plastic elongation, necking, and fracture.

[0034] The working principle of the present invention is:

[0035] After the cladding type tensile specimen is assembled, the whole is immersed in liquid metal. The liquid metal enters the gap between the parallel section 14 of the tensile specimen and the cladding shell 2 through the longitudinal notches on the upper shoulder 15 and the lower shoulder 16 and the longitudinal notch 23 on the side of the cladding shell 2. And the flowing liquid metal can enter the gap through the notch and continuously come into close contact with and act on the parallel section 14. After the infiltration experiment is completed, the whole cladding type tensile specimen is taken out of the liquid metal, and part of the liquid metal remains in the gap between the parallel section 14 and the cladding shell 2 under the capillary action. After cooling, the liquid metal solidifies. The whole cladding type tensile specimen is installed on a high-temperature vacuum material testing machine. After the installation is completed, an appropriate amount of solid liquid metal is placed in the funnel-shaped container 22. Vacuum is pumped, and the temperature is raised to the required experimental temperature to start stretching. The parallel section 14 generates tensile deformation, the distance between the upper shoulder 15 and the lower shoulder 16 increases, and the space between the parallel section 14 and the cladding shell 2 gradually increases. At this time, the solid metal in the funnel-shaped container 22 has melted and enters the gap through the longitudinal notch on the upper shoulder 15 under the capillary action to supplement the liquid metal, ensuring that the specimen is always in an environment infiltrated by liquid metal during the off-site stretching process.

[0036] The above is only one of the preferred embodiments of the present invention. It should be noted that for the applications in the technical field of the present invention, without departing from the technical principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A cladding type tensile specimen structure with a notched shoulder, characterized in that: It includes a tensile specimen (1) with a notched shoulder and a cladding shell (2). The cladding shell (2) closes and wraps around the outside of the tensile specimen (1) with a notched shoulder. The cladding shell (2) fixes the cladding shell (2) by clamping the upper shoulder of the tensile specimen (1) with a notched shoulder through the upper inner mouth protrusion (21); The tensile specimen (1) with a notched shoulder includes a connecting thread (11), an upper transition section (12), a lower transition section (13), a parallel section (14), an upper shoulder (15), and a lower shoulder (16). Each of the upper and lower ends of the tensile specimen (1) with a notched shoulder is provided with a connecting thread (11). The upper transition section (12) is between the connecting thread (11) at the upper end and the upper shoulder (15). The lower transition section (13) is between the connecting thread (11) at the lower end and the lower shoulder (16). The parallel section (14) is between the upper shoulder (15) and the lower shoulder (16). All parts are transitioned through arc chamfers; The cladding shell (2) is a two-piece closing shell. The inner diameter of the shell is slightly larger than the outer diameter of the shoulder. The inner mouth of the upper end of the cladding shell (2) is processed with a protrusion, and the inner diameter of the protrusion is slightly smaller than the outer diameter of the upper shoulder (15). A longitudinal notch (23) is processed at the side opening of the cladding shell (2). After the cladding shell (2) closes, the upper end forms a funnel-shaped container (22). The length of the cladding shell (2) should be sufficient to cover the total length of the parallel section (14) during the stretching process; The length of the upper transition section (12) ensures that the connecting thread (11) at the upper end is exposed from the funnel-shaped container (22). The length dimension of the lower transition section (13) ensures that the cladding shell (2) has sufficient installation length; There is a gap between the cladding shell (2) and the parallel section (14). The liquid metal enters the gap between the parallel section (14) of the tensile specimen and the cladding shell (2) through the longitudinal notches on the upper shoulder (15) and the lower shoulder (16) and the longitudinal notch (23) on the side of the cladding shell (2); After the tensile specimen (1) with a notched shoulder and the cladding shell (2) are taken out of the liquid metal, the liquid metal remains in the gap between the parallel section (14) and the cladding shell (2) by capillary action. After cooling, the liquid metal solidifies. The connecting thread (11) is a standard coarse thread, which is used to connect the material testing machine for tensile testing. The diameters of the upper transition section (12) and the lower transition section (13) are larger than the diameter of the parallel section (14), ensuring that the upper transition section (12) and the lower transition section (13) do not yield during the stretching process of the parallel section (14).

2. The cladding type tensile specimen structure with a notched shoulder according to claim 1, characterized in that: 6 longitudinal notches are opened on the upper shoulder (15) and the lower shoulder (16), and the 6 longitudinal notches are evenly distributed along the circumference.

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