CN105758740B - The small-sized torsional fatigue material mechanical property in-situ tester of controllable magnetic field intensity - Google Patents

Abstract

The invention relates to a small in-situ tester for the mechanical properties of torsional fatigue materials with controllable magnetic field strength, which belongs to the field of precision scientific instruments. It is mainly composed of precision drive unit, transmission unit, clamping unit, magnetic field loading unit, detection unit and support unit. The precision drive unit motor drives the rotating end of the clamping unit to reciprocate at a fixed angle through the reducer and the crank rocker mechanism in the transmission unit to realize torque fatigue load loading; by changing the crank, connecting rod and The rocker rod is long to realize the adjustment of torsional fatigue reciprocating deflection angle; by changing the pole head distance of the magnetic field loading unit, the magnetic field strength can be adjusted. The tester adopts a horizontal structure, which is simple and compact, and has good compatibility with an optical microscope. It can observe the sample in situ and in real time, and provides a reliable method for revealing the mechanical properties and fatigue damage mechanism of materials under the action of different magnetic field intensities. means of testing.

Description

Small in-situ tester for mechanical properties of torsional fatigue materials with controllable magnetic field strength

technical field

The invention relates to the field of precision scientific instruments and the field of in-situ mechanical testing, in particular to a small in-situ testing instrument for the mechanical properties of torsional fatigue materials with controllable magnetic field strength. The torsional fatigue test can be carried out on materials under different magnetic field strengths and different torsion angles, and the integrated optical microscope can be used to observe the samples in situ in real time, providing a new method for revealing the mechanical properties and fatigue damage mechanism of materials under different magnetic field strengths. Reliable means of testing.

Background technique

The purpose of material research and synthesis is to meet the needs of human material civilization, and a specific material has its specific performance is the root of its use value. The research object of the mechanical performance test is the performance of the material under the action of external force, such as elasticity, stiffness, strength, plasticity, hardness, impact toughness, fatigue strength and fracture toughness. According to statistics, fatigue damage accounts for about 80% of the total failure parts, seriously affecting personal safety and national economy, so it is of great significance to carry out fatigue research on materials.

In recent years, the use of optical microscopes, high depth-of-field microscopes, electron microscopes and other microscopic imaging systems for dynamic monitoring of material mechanical testing in-situ testing technology, real-time observation of deformation damage of materials under load, can deeply reveal the micro-mechanical behavior of materials , damage mechanism, and played a role in promoting the research and development of materials science.

Materials are often subjected to torsional fatigue loads in actual work, such as automobile drive shafts, machine tool spindles, motor shafts, etc. In addition, motor shafts and electric spindles are also in the magnetic field when they are subjected to torsional fatigue loads. At present, most of the torsional fatigue testing devices for materials are driven by servo motors, and the fatigue loads are controlled by inputting electric signals to control the forward and reverse rotation of the motors. The bulky devices cannot realize in-situ observations, and the loading of magnetic fields cannot be realized. Therefore, the development of a small in-situ test instrument for the mechanical properties of torsional fatigue materials with controllable magnetic field strength is of great significance for the study of the microscopic mechanical properties and fatigue damage mechanism of materials under torsional fatigue loads under different magnetic field strengths.

Contents of the invention

The object of the present invention is to provide a small in-situ tester for the mechanical properties of torsional fatigue materials with controllable magnetic field strength, which solves the above-mentioned problems in the prior art. The invention utilizes the principle of the crank rocker to convert the one-way rotation of the motor into the reciprocating rotation of the fixture with a fixed angle value, and adjusts the size of the fixed angle by changing the length of the crank, connecting rod and rocker rod in the crank rocker mechanism, and by changing the magnetic pole The pole head distance is used to adjust the strength of the loaded magnetic field, the torque is measured by the torque sensor connected to the fixed end fixture, and the reciprocating rotation angle and fatigue cycles are measured by the encoder connected to the rotating end fixture, so as to realize the difference when the motor does not commutate Torsional fatigue test of materials under the condition of magnetic field strength. The invention can perform in-situ dynamic monitoring on the deformation damage, microstructure change and performance evolution of the material during the loading process in combination with an optical microscope, and further conduct in-depth research on the mechanical properties and fatigue damage mechanism of the material under the action of different magnetic field intensities.

Above-mentioned purpose of the present invention is achieved through the following technical solutions:

The in-situ tester for the mechanical properties of small torsional fatigue materials with controllable magnetic field strength adopts a horizontal structure as a whole, which is simple and compact. Real-time observation. It includes a precision drive unit, a transmission unit, a clamping unit, a magnetic field loading unit, and a detection unit; the precision drive unit is fixed on one side of the base 20 through a motor bracket 4, and includes a motor encoder 1, a disc motor 2, and a reducer 3. The motor encoder 1 and the reducer 3 are respectively connected with the disc motor 2 to provide power for the whole instrument; the transmission unit is connected with the precision drive unit through the motor coupling 5, and is fixed on the base 20 by the support 23, and is connected with the The disc motor 2 is on the same side; the clamping unit is divided into two parts: a fixed-end clamping mechanism and a rotating-end clamping mechanism, which are respectively fixed on both sides of the base 20 through the clamp support II15 and the clamp support I21; The magnetic field loading unit is fixed in the middle of the base 20 by screws; the detection unit includes an encoder 6 and a torque sensor 17, the encoder 6 is fixed on the side of the support 23 through the support frame 7, and the torque sensor 17 is fixed on the base through the sensor support 18 20 away from the side of the disc motor 2.

The transmission unit includes a transmission shaft 22, a disk I8, a disk II9 and pin shafts I, II25, 26, the transmission shaft 22 is installed on the support 23 through a pair of bearings I24, and the transmission shaft 22 passes through the pin shaft I25 It is connected with the disc I8, and the disc I8 is connected with the disc II9 through the pin shaft II26 to form a crank rocker mechanism; the disc II9 obtains an axial direction on the rotating end fixture 10 through the bushing I28 and the circlip on both sides of the disc II9. Positioning, and connecting with the rotating end fixture 10 through a key to transmit torque; the transmission unit converts the full-circle rotary motion transmitted by the motor coupling 5 into disc II 9 to drive the rotating end fixture 10 to reciprocate at a fixed angle along its axis , so as to realize the loading of torsional fatigue load when the motor is running in one direction.

The transmission shaft 22, disk I8, and disk II9 are provided with evenly distributed pin shaft holes, and the crank, connecting rod and rocker in the crank-rocker mechanism are completed by adjusting the installation hole positions of the pin shaft I25 and the pin shaft II26. The adjustment of the length of the rod can change the reciprocating deflection angle of the rotary end fixture, and realize the adjustment of the torsional fatigue reciprocating deflection angle.

The rotating end clamping mechanism is composed of a rotating end fixture 10 and a pressing plate I11, the pressing plate I11 is connected with the rotating end fixture 10 through screws and compresses the sample, both of which are provided with grooves to hold the sample 32; The rotating end fixture 10 is installed on the fixture support I21 through the bearing II27. The rotating end fixture 10 is provided with a shaft shoulder and a spring groove, and the bearing II30 is positioned by pressing the disc II9 and the bushing I28 by the retaining spring.

The fixed-end clamping mechanism is composed of a fixed-end fixture 14 and a pressure plate II13, the pressure plate II13 is connected with the fixed-end fixture 14 by screws and compresses the sample, both of which are provided with grooves to clamp the sample 32; The fixed end fixture 14 is installed on the fixture support II15 through the bearing III31, the fixed end fixture 10 is processed with a shaft shoulder, and the bearing III31 is positioned by pressing the shaft sleeve II30 through the connecting shaft 16.

The magnetic field loading unit is composed of a pair of magnetic pole heads 12 and a magnet support 19. The two magnetic pole heads 12 are symmetrically arranged on both sides of the sample 32, and are fixed on the base 20 by the magnet support 19 to realize the magnetic field of the whole machine. Loading; at the same time, by adjusting the thickness of the gasket installed between the pole head and the magnet support, the distance between the two pole heads is changed, and the adjustment of the magnetic field strength of the sample is completed, and the test under the action of different magnetic field strengths is realized.

The detection unit is composed of an encoder 6 and a torque sensor 17, wherein the encoder 6 is connected with the rotary end fixture 10 through an encoder coupling 29 to realize the measurement of the reciprocating deflection angle and the fatigue cycle of the rotary end fixture; The sensor 17 is connected to the connecting shaft 16 by screws, so as to realize the measurement of the torque transmitted from the fixed end clamp 14 to the connecting shaft 16 through the key.

The main body size of the small in-situ tester for mechanical properties of torsional fatigue materials with controllable magnetic field strength is 296mm×80mm×60mm, which is compatible with optical microscopes.

The beneficial effect of the present invention is that the whole machine has a compact structure and good compatibility with an optical microscope, and can observe in real time changes in the microscopic morphology and tissue structure of materials when subjected to torsional fatigue under the action of different magnetic field strengths. Different from the traditional torsional fatigue mechanical performance testing device, it can realize the fatigue test in which the motor rotates in one direction to drive the sample to reciprocate torsion at a fixed rotation angle, and can be combined with an optical microscope to perform in-situ real-time torsion fatigue tests on materials under different magnetic field strengths. observe. In terms of drive, a typical crank-rocker mechanism composed of three discs connected by two pin shafts is used to achieve the purpose of torsional fatigue load loading without commutation of the motor, and at the same time, the installation position of the pin shafts can be changed to change the reciprocating swing angle of the rocker . In terms of applying the magnetic field, the instrument adopts a bipolar magnet with adjustable pole spacing, and the adjustment and control of the magnetic field strength is simple. In terms of the overall structure, the instrument has a compact structure and can be integrated with an optical microscope to monitor the sample in real time, realizing the in-situ dynamic observation of the microstructure morphology change, lattice change, and crack propagation of the material. In summary, the present invention has good application and development prospects, and is of great significance to the development of in-situ micromechanical performance testing technology of materials.

Description of drawings

The accompanying drawings described here are used to provide a further understanding of the present invention, and constitute a part of the application. The schematic examples and descriptions of the present invention are used to explain the present invention, and do not constitute improper limitations to the present invention.

Fig. 1 is the overall structure schematic diagram of the present invention;

Fig. 2 is a partial assembly schematic diagram of the transmission unit of the present invention;

Fig. 3 is a partial assembly schematic diagram of the fixing fixture of the present invention;

Fig. 4 is the local schematic diagram of sample installation of the present invention;

Fig. 5 is a schematic diagram of the front view structure of the present invention;

Fig. 6 is a top view structural schematic diagram of the present invention;

Fig. 7 is a left view structure diagram of the present invention;

Fig. 8 is the loading principle diagram of the present invention;

Fig. 9 is a schematic diagram of the adjustment of the crank mechanism of the present invention.

In the figure: 1. Motor encoder; 2. Disc motor; 3. Reducer; 4. Motor bracket; 5. Motor coupling; 6. Encoder; 7. Support frame; 8. Disc I; 9. Disc II; 10, rotating end fixture; 11, pressure plate I; 12, magnetic pole head; 13, pressure plate II; 14, fixed end fixture; 15, fixture support II; 16, connecting shaft; 17, torque sensor; 18 , sensor support; 19, magnet support; 20, base; 21, fixture support Ⅰ; 22, drive shaft; 23, support; 24, bearing Ⅰ; 25, pin shaft Ⅰ; 26, pin shaft Ⅱ; 27 , Bearing II; 28, Shaft I; 29, Encoder Coupling; 30, Shaft II; 31, Bearing III; 32, Sample.

Detailed ways

The detailed content of the present invention and its specific implementation will be further described below in conjunction with the accompanying drawings.

Referring to Figures 1 to 7, the in-situ tester for the mechanical properties of small torsional fatigue materials with controllable magnetic field strength of the present invention includes a precision drive unit, a transmission unit, a clamping unit, a magnetic field loading unit, a detection unit, and a support unit; The support unit described above is composed of a base 20 and a support, which plays a supporting role for other parts of the instrument; the precision drive unit is fixed on the side of the base 20 through a motor bracket 4, including a motor encoder 1, a disc motor 2, a deceleration 3, the motor encoder 1, and the reducer 3 are respectively connected with the disc motor 2 to provide power for the whole instrument; the transmission unit is connected with the precision drive unit through the motor coupling 5, and is fixed on the base by the support 23 20, on the same side as the motor; the clamping unit is divided into two parts: a fixed end clamping mechanism and a rotating end clamping mechanism, which are respectively fixed on both sides of the base 20 by the clamp support II15 and the clamp support I21 The magnetic field loading unit is fixed in the middle of the base 20 by screws; the detection unit includes an encoder 6 and a torque sensor 17, the encoder 6 is fixed on the side of the support 23 through the support frame 7, and the torque sensor 17 is supported by the sensor The seat 18 is fixed on the side of the base 20 away from the motor. The whole machine adopts a horizontal structure, which is simple and compact. It can perform in-situ real-time observation of the mechanical properties, microstructure morphology, and fracture cracks of materials exhibited by torsional fatigue under different magnetic field strengths.

Referring to Fig. 1 and Fig. 2, the transmission unit is mainly composed of a transmission shaft 22, a disc I8, a disc II9 and pin shafts 25, 26; wherein the transmission shaft 22 is installed on the support 23 through a pair of bearings I24 , the thin shaft end is connected with the output shaft of the precision drive unit through the motor coupling, and the disc end is connected with the disc I8, and the disc I8 and the disc II9 are respectively connected by pin shafts I25 and II26 to form a crank rocker mechanism; Both sides of disc II 9 are axially positioned on the rotating end fixture 10 through the shaft sleeve I28 and the circlip respectively, and are connected with the rotating end fixture 10 with a key to transmit torque; Driven by the torque of the whole circle, the disc I8, which acts as a connecting rod, drives the disc II9 and the fixture 10 to rotate reciprocally, that is, the transmission unit converts the full circle rotary motion transmitted by the motor coupling 5 into a disc II9 drives the rotating end fixture 10 to reciprocate and rotate along its axis at a fixed angle, so as to realize the loading of the torsional fatigue load when the motor operates in one direction.

Referring to Fig. 1, Fig. 2 and Fig. 4, the rotating end clamping mechanism is composed of a rotating end fixture 10 and a pressure plate I11, which are connected by screws to compress the sample, both of which are processed with grooves to facilitate the sample 32 clamping; the rotating end fixture 10 is installed on the fixture support I21 through the bearing II27, and the rotating end fixture 10 is processed with a shaft shoulder and a spring groove, and the disc II9 and the shaft sleeve I28 are pressed by the retaining spring to make Bearing II30 is positioned.

Referring to Fig. 1, Fig. 3 and Fig. 4, the fixed-end clamping mechanism is composed of a fixed-end clamp 14 and a pressure plate 13, which are connected by screws to compress the sample, both of which are processed with grooves to facilitate the sample 32 clamping; the fixed end fixture 14 is installed on the fixture support II15 through the bearing III31, the fixed end fixture 10 is processed with a shaft shoulder, and the bearing III31 is positioned by pressing the shaft sleeve II30 through the connecting shaft 16.

Referring to Fig. 1, Fig. 2 and Fig. 3, the detection unit is composed of an encoder 6 and a torque sensor 17; wherein the encoder 6 is fixed on the support frame 7 by screws, and the support frame 7 is fixed on the support 23 by screws Above, the encoder 6 is connected to the rotary end fixture 10 through the encoder coupling 29; during the torsional fatigue test, the rotation of the rotary end fixture 10 drives the input shaft of the encoder 6 to rotate through the encoder coupling 29, realizing the reciprocation of the rotary end fixture Measurement of deflection angle and fatigue cycles. The torque sensor 17 is fixed on the sensor support 18, and is connected with the connecting shaft 16 by screws, and the connecting shaft 16 is connected with the fixed end fixture 14 by a key; during the torsional fatigue test, the fixed end fixture 14 transmits the torque to the The torque sensor 17 realizes the measurement of the torque in the test.

Referring to Fig. 1, Fig. 4 and Fig. 8, the magnetic field loading unit is composed of a pair of magnetic pole heads 12 and a magnet support 19, and the two magnetic pole heads 12 are symmetrically arranged on both sides of the torsion sample 32, realizing the complete machine Magnetic field loading; at the same time, by adjusting the thickness of the installation gasket between the pole head and the magnet support, the distance d between the two pole heads is changed to complete the adjustment of the magnetic field strength of the sample and realize the test under different magnetic field strengths.

Referring to Fig. 2 and Fig. 9, the transmission shaft 22, disk I8, and disk II9 are punched with evenly distributed pin holes, and the crank rocker can be adjusted by adjusting the installation holes of pin I and pin II. The adjustment of the length of the crank, connecting rod and rocker rod in the mechanism can change the size of the reciprocating deflection angle of the fixture at the rotating end, and realize the adjustment of the torsional fatigue reciprocating deflection angle. When the pin shaft holes in different positions are used to connect the transmission shaft 22, the disk I8, and the disk II9, the crank in the crank rocker mechanism ,link and rocker respectively adjusted to , , , to realize the adjustment of the length of each rod, thereby changing the size of the reciprocating deflection angle of the rotary end fixture, and completing the adjustment of the torsional fatigue reciprocating deflection angle.

Referring to Fig. 1, Fig. 5, Fig. 6 and Fig. 7, the test instrument has a compact structure, the main body size is 296mm × 80mm × 60mm, it has good compatibility with optical microscopes, and can observe in real time under different magnetic field strengths Changes in the microscopic morphology and structure of materials when subjected to torsional fatigue loads.

The present invention can carry out the mechanical test of the torsional fatigue loading under the action of the magnetic field, in addition to obtaining the torque-torsion angle curve under the action of different magnetic field intensities, the torsional fatigue curve and the microscopic shape of the sample in the test, it can also obtain the torque-torsion angle curve according to the The material shear modulus G is obtained in the linear stage, and the fatigue notch sensitivity is tested on pre-notched specimens Detection, etc., the related formula is as follows

Shear modulus G

in, is the torque increment, is the twist angle increment, is the gauge length, is the sample diameter;

mean stress

stress amplitude

Stress ratio r

in is the maximum stress, is the minimum stress;

Fatigue Notch Sensitivity

in is the theoretical stress concentration factor, is the fatigue notch coefficient.

Referring to Figs. 1 to 4 and shown in Fig. 8, the concrete work process of the present invention is as follows:

At the beginning of the test, the disc motor 2, which received the input electrical signal, was slowed down by the reducer 3 to increase the torque and drive the transmission shaft 22 to rotate through the motor coupling 5. Based on the crank rocker principle, the transmission shaft 22 drives the disc II 9 along the The disc II 9 axis reciprocates at a fixed angle, and the disc II 9 drives the rotating end fixture 10 and the torsional specimen 32 clamped on the fixture to reciprocate and rotate, while the torsional specimen 32 is clamped by the fixed end fixture 14, finally realizing the torsional fatigue load Loading; the two pole heads 12 of the magnetic field unit are symmetrically arranged on both sides of the torsion sample 32 to complete the magnetic field loading, and the magnetic field intensity is changed by increasing or reducing the distance d between the two pole heads 12 . At the same time, the thin shaft end of the rotating end fixture 10 drives the input shaft of the encoder 6 to rotate through the encoder coupling 29 to complete the collection of test fatigue times and single reciprocating angle values; the fixed end fixture 14 transmits the test torque through the connecting shaft 16 For the torque sensor 17, the collection of the test torque is completed. The adjustment of the reciprocating rotation angle value of the fatigue test sample is completed by changing the installation hole positions of the two pin shafts between the transmission shaft 22, the disc I8 and the disc II9. The whole machine can be placed under an optical microscope, and the sample is polished and corroded before the test, so that the in-situ observation of the microstructure of the sample during the test can be realized.

The above descriptions are only preferred examples of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made to the present invention shall be included within the protection scope of the present invention.

Claims (7)

1. The utility model provides a small-size torsional fatigue material mechanical properties normal position tester of controllable magnetic field intensity which characterized in that: the whole body adopts a horizontal structure and comprises a precision driving unit, a transmission unit, a clamping unit, a magnetic field loading unit and a detection unit; the precision driving unit is fixed on one side of the base (20) through a motor bracket (4) and comprises a motor encoder (1), a disc type motor (2) and a speed reducer (3), and the motor encoder (1) and the speed reducer (3) are respectively connected with the disc type motor (2) to provide power for the whole instrument; the transmission unit is connected with the precision driving unit through a motor coupler (5), is fixed on the base (20) through a support (23), and is positioned at the same side of the disc motor (2); the clamping unit is divided into a fixed end clamping mechanism and a rotating end clamping mechanism, and is respectively fixed on two sides of the base (20) through a clamp support II (15) and a clamp support I (21); the magnetic field loading unit is fixed in the middle of the base (20) through a screw; the detection unit comprises an encoder (6) and a torque sensor (17), the encoder (6) is fixed on the side surface of the support (23) through a support frame (7), and the torque sensor (17) is fixed on one side, far away from the disc type motor (2), of the base (20) through a sensor support (18);

the transmission unit comprises a transmission shaft (22), a disc I (8), a disc II (9) and pin shafts I, II (25, 26), the transmission shaft (22) is installed on a support (23) through a pair of bearings I (24), the transmission shaft (22) is connected with the disc I (8) through the pin shaft I (25), and the disc I (8) is connected with the disc II (9) through the pin shaft II (26) to form a crank rocker mechanism; the disc II (9) is axially positioned on the rotating end clamp (10) through the shaft sleeves I (28) on the two sides of the disc II and the clamp springs, and is connected with the rotating end clamp (10) through keys to transmit torque; the transmission unit converts the whole-circle rotary motion transmitted by the motor coupler (5) into reciprocating rotation of the rotating end clamp (10) driven by the disc II (9) along the axis of the rotating end clamp at a fixed angle, so that the loading of the torsional fatigue load during the unidirectional operation of the motor is realized.

2. The small torsional fatigue material mechanical property in-situ tester with controllable magnetic field strength of claim 1, which is characterized in that: the transmission shaft (22), the disc I (8) and the disc II (9) are provided with pin shaft holes which are uniformly distributed, and the adjustment of the lengths of a crank, a connecting rod and a rocker rod in the crank rocker mechanism is completed by adjusting the mounting hole positions of the pin shaft I (25) and the pin shaft II (26), so that the reciprocating deflection angle of the clamp at the rotating end is changed, and the adjustment of the reciprocating deflection angle of the torsional fatigue is realized.

3. The small torsional fatigue material mechanical property in-situ tester with controllable magnetic field strength of claim 1, which is characterized in that: the rotating end clamping mechanism consists of a rotating end clamp (10) and a pressing plate I (11), the pressing plate I (11) is connected with the rotating end clamp (10) through a screw and presses a sample tightly, and both the rotating end clamp and the pressing plate are provided with grooves for clamping the sample (32); the rotary end fixture (10) is installed on the fixture support I (21) through the bearing II (27), a shaft shoulder and a clamp spring groove are arranged on the rotary end fixture (10), and the bearing II (27) is located by compressing the disc II (9) and the shaft sleeve I (28) through the clamp spring.

4. The small torsional fatigue material mechanical property in-situ tester with controllable magnetic field strength of claim 1, which is characterized in that: the fixed end clamping mechanism consists of a fixed end clamp (14) and a pressing plate II (13), the pressing plate II (13) is connected with the fixed end clamp (14) through a screw and compresses a sample, and both the pressing plate II and the pressing plate are provided with grooves for clamping the sample (32); the fixed end clamp (14) is arranged on the clamp support II (15) through a bearing III (31), a shaft shoulder is machined on the fixed end clamp (10), and the shaft sleeve II (30) is compressed through the connecting shaft (16) so that the bearing III (31) is positioned.

5. The small torsional fatigue material mechanical property in-situ tester with controllable magnetic field strength of claim 1, which is characterized in that: the magnetic field loading unit consists of a pair of magnetic pole heads (12) and a magnet support (19), wherein the two magnetic pole heads (12) are symmetrically arranged at two sides of the sample (32) and are fixed on the base (20) through the magnet support (19), so that the magnetic field loading of the whole machine is realized; meanwhile, the distance between the two magnetic pole heads is changed by adjusting the thickness of a gasket arranged between the magnetic pole heads and the magnet support, so that the adjustment of the magnetic field intensity of the sample is completed, and the test under the action of different magnetic field intensities is realized.

6. The small torsional fatigue material mechanical property in-situ tester with controllable magnetic field strength of claim 1, which is characterized in that: the detection unit consists of an encoder (6) and a torque sensor (17), wherein the encoder (6) is connected with the rotating end clamp (10) through an encoder coupler (29), so that the reciprocating deflection angle of the rotating end clamp and the fatigue frequency are measured; the torque sensor (17) is connected with the connecting shaft (16) through a screw, so that the torque transmitted to the connecting shaft (16) by the fixed end clamp (14) through a key is measured.

7. The small torsional fatigue material mechanical property in-situ tester with controllable magnetic field strength of claim 1, which is characterized in that: the small torsional fatigue material mechanical property in-situ tester with controllable magnetic field strength has a main body size of 296mm multiplied by 80mm multiplied by 60mm, and is compatible with an optical microscope.