UA15157U - Device for micromechanical tests - Google Patents

Abstract

The proposed device for micromechanical tests contains an optical-mechanical hardness meter, clamps for the samples, and a force transducer. The hardness meter contains a base member, which is installed at the worktable of the device, a measuring microscope, and a loading unit with an indenter. At the worktable, a rectangular attachment is installed that consists of four strips that are joined together. Two strips are used as guides for two demountable clamps with holes. One of the clamps is used for axially tensioning the sample, and the other is used for axially compressing the sample. Each clamp contains two plates, between which the sample to be tested can be installed. One of the plates reacts to tension or compression load. The other plate is coupled with the force transducer. The surface of this plate has a polished area for focusing the optical system of the optical-mechanical hardness meter.

Description

Description of the invention

The useful model relates to testing equipment, in particular devices for studying the strength characteristics of 2 materials and can be used to conduct hardness tests while simultaneously creating in samples either uniaxial tension or uniaxial compression.

The well-known device for micromechanical tests (author's certificate of the USSR Mo1567920, M cl. 501M3/08, bulletin Mo20, 1990) is intended for testing microsamples both in tension and compression. The device includes a housing, a damping device, which includes a screw and a pusher with a guide, an active and passive 70 sample gripper, a frame and a force meter installed inside it along the axis of the grippers. In addition, the device is supplied with a movably installed, relative to the mandrel, frame with a hole in one of the shelves, fixed on the frame symmetrically to the axis of the grippers by two plates with a pair of through grooves in each and placed in the grooves by pins rigidly connected to the active gripper, and the guide of the pusher placed in the opening of the frame shelf.

When testing a sample for tension, a pusher connected by a guide with a deforming screw moves the frame 12, which covers the frame and interacts with the force meter. At the same time, the plates attached to the frame interact with the pins of the active grip, creating tensile forces in the sample. During the compression test, the pusher interacts with the frame, and the frame interacts with the active gripper.

However, the known device cannot be used to perform hardness tests while simultaneously creating in the samples either uniaxial tension or uniaxial compression, because the test of the samples for both tension and compression is carried out without hardness tests.

The device for measuring microhardness, M.M. Khrushchev, E.S. Berkovich, is the closest to the proposed solution in terms of its technical essence and effect. Devices PMT-2 and PMT-3 for microhardness testing. M., 1950) is intended for testing samples for microhardness. The device contains: a tripod, consisting of a base and a column, which has an external tape thread for moving the column with an optical tube in a vertical 22 position using a nut; a stage that moves in two mutually perpendicular directions and a load mechanism unit that rotates around its axis.

The principle of operation is based on pressing a diamond tip (pyramid) into the material under study under a specified load and measuring the linear value of the diagonal. The number of microhardness is determined by the distribution of the normal load applied to the diamond tip on the conventional area of the side surface - the resulting impression: no - PE. I am 8

However, the known device cannot be used to conduct hardness tests with simultaneous creation of uniaxial tension or uniaxial compression in the samples, because the hardness test of the samples is not performed in conjunction with the uniaxial test of the samples tension or uniaxial compression. --

The purpose of the proposed useful model "Device for micromechanical testing" is to increase the functionality of the device by conducting hardness tests while simultaneously creating either uniaxial tension or uniaxial compression in the samples. « du The solution to the given problem is achieved with the help of a device for micromechanical tests, which consists of an optical-mechanical device for hardness tests and an attachment, located on a stage, to create in the samples either uniaxial tensile force, or one- axial force from compression. The optical-mechanical device for measuring hardness includes a base with a rotating stage relative to its vertical axis and a rigid column with a bracket that moves along its axis, which supports a measuring microscope with a loading device carrying an indenter. - 395 The attachment to the device for micromechanical tests is shown in (Fig. 1) and consists of a rectangular body (1) in the form of four rigidly interconnected bars, two sets of sequentially installed 1 replaceable grippers with holes, one of the sets is designed to provide in samples of uniaxial tension, and the other one of uniaxial compression, each set of grippers is made in the form of two plates, while one of the plates is an active gripper (2), and the other plate is a passive gripper (3), a lever ( 4), a force-meter, which (9) 50 consists of a force-measuring bracket (5) and an hour-type arrow indicator (6), on the surface of the passive gripper (3) there is a polished platform (7) that is intended for focusing optical system of an optical-mechanical device.

The device works as follows.

One of the sets of grippers (2, 3) is installed in the body (1) of the attachment, designed to create both uniaxial tension and 99 uniaxial compression in the samples, depending on which force c is intended to be applied to the sample: tension or compression After that, the sample is fixed in the grips (2, 3) and the attachment is placed on the object table of the optical-mechanical device. The loading force is transmitted to the sample with the help of the lever (4) through the active gripper (2) and through the passive gripper (3) is perceived by the force-measuring clamp (5) and recorded by the arrow indicator (6). After that, with the help of an optical-mechanical device 60 according to the standard method, the sample, loaded with the help of the attachment, is tested for hardness. The difference from the standard method of conducting hardness tests is that the focusing of the optical-mechanical device before pressing the indenter into the sample does not take place on the surface of the sample, but on the polished platform (7), made in the same plane as the surface of the sample, on the surface of the passive gripper ( 3). because Example One of the sets of grippers was installed in the attachment designed to create either uniaxial tension or uniaxial compression in the samples, depending on which force is expected to be applied: tension or compression. A sample made of X18NI10 steel was fixed in the grips. Previously, on one of the flat surfaces of the sample, according to the generally accepted method, a microsand was prepared for conducting tests on

Microhardness. The console was placed on the object table of the optical-mechanical device. A loading force of 150, 300, 400, 550, 650OH was successively applied to the lever and transferred to the sample through an active gripper. The magnitude of the load was recorded using an arrow indicator. The magnitude of the stress created in the sample was calculated by the formula: -- РЕ t Ка , where Р is the amount of the applied force; 5 - cross-sectional area of the sample.

After that, the Knoop microhardness test was performed on the sample, which is under the influence of an external load, on its polished surface, while the long diagonal of the Knoop indenter was oriented, respectively, parallel and perpendicular to the direction of the applied force. Hardness according to 19 Knoop was calculated using the formula:

R R

Nk---5A--' ni pe de 5 - the area of the print projection;

P - pressing force in H; a - the size of the long diagonal in m.

After that, a graph was built in coordinates: NK-5 (Fig. 2).

Thus, in comparison with the prototype, the use of the proposed device will allow hardness testing with the simultaneous creation of both uniaxial tension and uniaxial compression, which will allow evaluating the effect of residual stresses on the strength characteristics of materials. -

The device can be used both for research purposes in the creation of new materials, and in industrial production to control the quality of the obtained products.

Claims (1)

The formula of the invention - IF) A device for micromechanical tests, which includes an optical-mechanical device for measuring hardness, which includes a base with a rotating stage relative to its vertical axis and a rigid column with a bracket that moves along its axis, which supports a measuring microscope with o Ззв5 a loading device that carries an indenter, which differs in that it has an attachment located on the same stage, which is a rectangular body in the form of four rigidly interconnected bars, of which two bars are located one against the other, are guides for placing two sets of sequentially installed replaceable grippers with holes, one of these sets is designed to provide uniaxial tension in the samples, and the other - uniaxial compression, each set of grippers is made in the form of two plates, which together form a flat surface, and are intended to place between them the tested sample with thickness, while one of the pla the plate is an active gripper that perceives the loading force from the lever, and the other plate is a passive gripper connected to a force gauge installed along the axis of the grippers, which h . . oh . Kk and? consists of a force-measuring bracket and an indicator, on the surface of the passive gripper, in the same plane as the surface of the sample, there is a polished platform designed for focusing the optical system of the Optical-Mechanical Device. - 1 - 1 that 60 b5