A demonstration teaching aid for elastic deformation and plastic deformation of metal materials and its assembly method

Abstract

The present invention discloses a demonstration teaching aid for elastic deformation and plastic deformation of metal materials and an assembly method thereof. The end face of one side of half mold A and the corresponding end face of one side of half mold B form a demonstration surface. The demonstration surface of half mold A is provided with at least one row of metal atomic models parallel to the relative moving direction of half mold A and half mold B, and the corresponding demonstration surface of half mold B is provided with at least one row of metal atomic models matching the position of the metal atomic models of half mold A. A lattice line model is provided between any two adjacent metal atomic models in the same demonstration surface; a reset device and a positioning device are provided between half mold A and half mold B, and the positioning device is provided with multiple positioning positions within the relative sliding range of half mold A and half mold B. It can be seen from the above structure that the demonstration teaching aid for elastic deformation and plastic deformation of metal materials of the present invention realizes the specific demonstration of the principle of elastic deformation and plastic deformation of metal from the microscopic perspective of the lattice through the function of the teaching aid.

Description

Technical Field

[0001] The invention relates to the technical field of demonstration teaching aids, and in particular to a demonstration teaching aid for elastic deformation and plastic deformation of metal materials and an assembly method thereof. Background Art

[0002] 1.1 Concept of Slip

[0003] There are two modes of plastic deformation: slip and twinning. Plastic deformation mainly occurs in the form of slip, and the present invention is only focused on the slip mode.

[0004] Slip means that under the action of external force, one part of the metal crystal slides relative to another part along a certain crystal direction on a certain crystal plane. The external force acting on the metal crystal can be decomposed into a component perpendicular to the slip plane and a component parallel to the slip plane according to the orthogonal decomposition method, see Figure 1 a. Among them, the component force perpendicular to the slip plane can only cause elastic deformation and has no effect on slip. Only the component force parallel to the slip plane can cause the two parts of the metal crystal to slide relative to each other. Therefore, in order to simplify the problem, the external force is set to be the force F and F' parallel to the slip plane. These two forces are equal in magnitude and opposite in direction. Figure 1 As shown in b.

[0005] 1.2 Definition of elastic deformation and plastic deformation

[0006] Metal crystals deform under the action of external force. The part of the deformation that disappears after the external force is removed is called elastic deformation; the part of the deformation that can be permanently retained is called plastic deformation.

[0007] When the external force is relatively small, the metal crystal only produces elastic deformation. At this time, when the external force is removed, the metal crystal will completely restore its original shape and size. The amount of elastic deformation produced is proportional to the magnitude of the external force, satisfying Hooke's law, but there is a maximum value, which is related to the elastic limit of the metal crystal.

[0008] When the external force exceeds a certain value (the stress caused exceeds the elastic limit of the material), the elastic deformation no longer increases, and the increased deformation is plastic deformation. When the external force is removed, the elastic deformation disappears, but the plastic deformation does not disappear, but remains permanently. The size of the plastic deformation is related to the size of the external force and the plasticity of the metal crystal. Obviously, the greater the external force, the greater the plastic deformation; the better the plasticity of the metal crystal, the greater the plastic deformation after fracture.

[0009] 1.3 The nature of elastic deformation

[0010] like Figure 2As shown in a, metal crystals are composed of atoms arranged in a certain regular period. The atoms are at the nodes of the lattice and have the lowest energy state. Therefore, the nodes are the equilibrium positions of the atoms. Figure 2 As shown in Figure b, under the action of external force, atoms will deviate from their equilibrium position and be in a non-equilibrium position with a high energy state. Atoms that deviate from the equilibrium position are affected by the repulsive or attractive forces of the surrounding atoms, which is equivalent to elastic force. Therefore, they have high elastic potential energy and are in an unstable state, with a tendency to transform to a low energy state (equilibrium state).

[0011] like Figure 2 As shown in c, the external force is removed, and under the action of the elastic force between the surrounding atoms, the atoms that deviate from the equilibrium position return to their original equilibrium position, that is, they return from the high energy state to the lowest energy state.

[0012] Therefore, elastic deformation is essentially caused by the deviation of atoms from their equilibrium positions, and the amount of elastic deformation produced by a single atom does not exceed the equilibrium distance of one atom.

[0013] 1.4 The nature of plastic deformation

[0014] like Figure 3 As shown in a, when the external force exceeds a certain value, the distance that the atoms move will be greater than the equilibrium distance of an atom. Therefore, in addition to elastic deformation, plastic deformation also occurs. Figure 3 As shown in Figure b, when the external force is removed, the atoms that deviate from the equilibrium position can no longer return to the original equilibrium position, but can only return to the equilibrium position that has been crossed. The atoms in this equilibrium position also have the lowest energy state, so they can exist permanently and form plastic deformation. Therefore, plastic deformation is essentially caused by atoms sliding from one equilibrium position to another. Obviously, the amount of plastic deformation is the difference between the total deformation and the maximum elastic deformation, which should be an integer multiple of the interatomic distance.

[0015] 1.5 Teaching status of metal materials courses

[0016] Metallurgy and Heat Treatment is a required basic course for students majoring in mechanics and related mechanics. Teachers in many schools reported that students generally disliked the course, and the phenomenon of skipping classes or hidden skipping classes was serious. The teachers' efforts were not proportional to the students' gains, and the teaching effect was poor. The main reason is that the course involves many concepts, complicated knowledge points, abstract theories, and is difficult to understand. Therefore, teachers need to continuously improve teaching methods and refine teaching content.

[0017] 1.6 Theoretical core of metal materials course

[0018] The main teaching line of the metal material course is the strengthening method of metal materials, including strengthening theory and practice. Only by mastering the theory can we better guide the practice, so the teaching of metal material strengthening theory occupies an important position in the course.

[0019] Learning any theory is like untangling a tangled mess, and you must first find the end of the rope. The end of the rope in the theory of strengthening metal materials is the knowledge of elastic deformation and plastic deformation, especially plastic deformation. The essence of plastic deformation is the result of atomic movement. Therefore, being able to hinder atomic movement can improve the strength of metal materials. The main way to hinder atomic movement is to cause lattice defects. Simply put, it is to turn regularly arranged atoms into irregularly arranged atoms, so that as many atoms as possible deviate from their equilibrium positions. Atoms that deviate from the equilibrium position have high energy states and vibrate violently, thereby hindering the movement of other atoms.

[0020] 1.7 Insufficiency of existing teaching methods

[0021] Since the nature of plastic deformation plays such a programmatic role in the course theory, it is particularly necessary to strengthen the teaching of this part. At present, there are two common ways to explain the knowledge of plastic deformation and slip, one is to use graphic demonstration and the other is to use animation demonstration.

[0022] The shortcoming of graphic demonstration is that it only shows the result but not the process, and can only express the initial and final states, such as Figure 4 . Figure 4 a expresses the original state of the metal crystal, Figure 4 b expresses the state of elastic deformation + plastic deformation. Figure 4 c expresses the state of plastic deformation. Obviously, since there is no change process, it is less intuitive.

[0023] Animation demonstration is to Figure 4 The movement process of the upper and lower parts is shown, which is much more intuitive than graphic demonstration, but the credibility is relatively low, and students cannot feel the changes in the force.

[0024] Therefore, both of the above demonstration methods have defects and cannot reflect the change process from elastic deformation to plastic deformation and then to greater plastic deformation as the force increases, let alone the process of elastic recovery of the material after the external force is removed. Therefore, it is necessary to develop a teaching physical model so that students can feel the influence of force on the crystal slip process after operation and see the basic process of slip and elastic recovery.

[0025] At present, there is a technical gap and a market gap in terms of teaching aids for elastic deformation and plastic deformation of metal materials. Summary of the invention

[0026] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a demonstration teaching aid for elastic deformation and plastic deformation of metal materials and an assembly method thereof. Through the role of the teaching aid, the principle of elastic deformation and plastic deformation of metal is specifically demonstrated from the microscopic perspective of the lattice; the use of elastic-plastic deformation teaching models to carry out teaching related to elasticity and plastic deformation can not only overcome the shortcomings of schematic teaching without a change process, but also overcome the shortcomings of animation teaching without a sense of the magnitude of force, and it has significant advantages of being real and credible. During the teacher's demonstration or the student's operation, the magnitude of the force, the deformation and the recovery process can be experienced, and this objective feeling is obviously helpful for understanding the knowledge of slip. In the field of related material science teaching, it has certain promotion value; the process of metal elastic deformation and plastic deformation is demonstrated by the teaching aid, and the demonstration effect is more specific, more vivid, and more perceptual, which is convenient for students to understand the principles of elastic deformation and plastic deformation; the structure is exquisite, easy to mass produce, and the disassembly and assembly of the teaching aid is very convenient.

[0027] The technical solution adopted by the invention is:

[0028] A demonstration teaching aid for elastic deformation and plastic deformation of metal materials, comprising a half mold A and a half mold B that match each other, wherein the contact surfaces of the half mold A and the half mold B are slidably connected to each other, a side end surface of the half mold A and a corresponding side end surface of the half mold B form a demonstration surface, at least one row of metal atomic models parallel to the relative movement direction of the half mold A and the half mold B is provided on the demonstration surface of the half mold A, at least one row of metal atomic models matching the position of the metal atomic models of the half mold A is provided on the corresponding demonstration surface of the half mold B, a lattice line model is provided between any two adjacent metal atomic models in the same demonstration surface, and the distance between any two adjacent metal atomic models is equal; the contact surface of the half mold A and the half mold B is located between two adjacent rows of metal atomic models, a resetting device and a positioning device are provided between the half mold A and the half mold B, and the positioning device is provided with a plurality of positioning positions within the relative sliding range of the half mold A and the half mold B, and the distance between two adjacent positioning positions is equal to the spacing between two adjacent metal atomic models;

[0029] When the positioning device is located at any positioning position, the lattice line model of the metal atom model of at least one half mold A is aligned with the lattice line model of the metal atom model of the half mold B;

[0030] When half mold A moves relative to half mold B in a direction opposite to the resetting force of the resetting device under the action of external force, the resetting force generated by the resetting device drives half mold A to move relative to half mold B to the closest positioning position.

[0031] A further improvement of the present invention is that the reset device includes a transmission rod fixed to half-mold A and a core rod fixed to half-mold B, the core rod is parallel to the direction of relative movement of half-mold A and half-mold B, both ends of the core rod are fixed to half-mold B, and a pre-loaded spring A is also sleeved on the core rod, one end of the spring A is in contact with the transmission rod, and the other end is fixed relative to the core rod.

[0032] A further improvement of the present invention is that the core rod is fixed in the strip groove A provided in the half mold B, the notch of the strip groove A faces the half mold A, and the end of the transmission rod away from the half mold A extends from the notch into the strip groove A and connects with the core rod.

[0033] A further improvement of the present invention is that when the transmission rod moves from one end of the slot along the core rod to the other end of the slot, the positioning device passes through all the positioning positions.

[0034] A further improved solution of the present invention is that the transmission rod is provided with a sliding hole matching the core rod, and the sliding hole matches the core rod.

[0035] A further improved solution of the present invention is that the two ends of the spring A are respectively fixed to the spring bracket, and the two ends of the spring A are respectively fixed to the transmission rod and the core rod through the spring bracket.

[0036] A further improvement of the present invention is that the end of the transmission rod facing the half-mold A extends into the through hole A provided in the half-mold A, the end of the transmission rod located in the through hole A is provided with an enlarged head, and the end of the through hole A facing away from the half-mold B is provided with a flared opening matching the enlarged head, the opening of the flared opening is connected to the flared opening by a tightening bolt, and the enlarged head is fixed at the connection between the flared opening and the through hole A, at which time the core rod matches the position of the sliding hole.

[0037] A further improvement of the present invention is that both ends of the strip groove A pass through the half mold B, and both ends of the core rod are fixed to the end caps A and B provided at both ends of the strip groove A respectively.

[0038] A further improvement of the present invention is that the end cover A and the end cover B are respectively provided with a through hole B, and the through holes B of the end cover A and the end cover B are respectively connected to the corresponding ends of the core rod, one end of the core rod and the through hole B are interference fit, and the other end of the core rod and the through hole B are clearance fit.

[0039] A further improvement of the present invention is that the end cover A and the end cover B are fixed to the half mold B by fastening screws respectively.

[0040] A further improvement of the present invention is that the end surfaces of the end caps A and B facing away from the half-mold B are flush with the end surfaces of the corresponding sides of the half-mold B.

[0041] A further improvement of the present invention is that there are a plurality of core rods, which are arranged parallel to each other.

[0042] A further improvement of the present invention is that the positioning device includes a positioning pin arranged on the end surface of half mold A facing half mold B, the end of the positioning pin facing away from half mold B is located in a slot hole provided in half mold A, and the end of the positioning pin facing away from half mold B is reciprocated along the direction facing or away from half mold B by a spring B, the spring B is provided with a pre-pressure, and positioning grooves matching the positioning pin are respectively provided at the positioning positions on the end surface of the half mold B facing away from the half mold A. When the positioning pin is located in any one of the positioning grooves, the lattice line model of the metal atomic model of at least one half mold A is connected to the lattice line model of the metal atomic model of half mold B.

[0043] A further improvement of the present invention is that the end of the slot hole facing away from the half mold B passes through the half mold A and is threadedly connected with a fixing screw, and one end of the spring B contacts the end of the fixing screw.

[0044] A further improved solution of the present invention is that the end of the positioning pin facing the positioning groove is a ball head, and the positioning groove is a matching spherical arc surface groove.

[0045] A further improvement of the present invention is that a strip groove B is provided in the middle of the contact surface between the half mold B and the half mold A along the relative movement direction between the half mold A and the half mold B, a matching slide bar is provided in the middle of the contact surface between the half mold A and the half mold B corresponding to the strip groove B, and a limit groove parallel to the strip groove B is symmetrically provided on the inner side of the groove wall of the strip groove B, and a matching limit rod is provided on the side wall of the slide bar corresponding to the limit groove.

[0046] A further improved solution of the present invention is that when the limiting rod moves along the limiting groove from one end to the other end of the limiting groove, the positioning pin passes through all the positioning grooves.

[0047] A further improvement of the present invention is that the limiting groove passes through the side wall of the strip groove B corresponding to the end of the spring A in the opposite direction of the preload force.

[0048] A further improvement of the present invention is that a notch is provided at one end of the contact surface between the half mold A and the half mold B, which is located in the opposite direction of the pre-force of the spring A, and the length of the notch along the direction parallel to the relative movement direction of the half mold A and the half mold B is greater than or equal to the maximum stroke of the relative movement of the half mold A and the half mold B.

[0049] A further improvement of the present invention is that the two opposite corresponding side end surfaces of the half mold A and the half mold B are both demonstration surfaces.

[0050] A further improvement of the present invention is that when the adjacent end faces of the half-mold A and the half-mold B are aligned, the locating pin is located in a locating groove at one end of a row of locating positions.

[0051] The assembly method of the demonstration teaching aid as described above comprises the following steps:

[0052] 1) First, place the end of half mold A with the notch facing away from half mold B, and align the sliding bar of half mold A with the strip groove of half mold B, and align the limit rod with the limit groove;

[0053] 2) Then, move the mold half A relative to the mold half B along the direction of the limiting rod and the limiting groove until the adjacent end faces of the mold half A and the mold half B are aligned;

[0054] 3) Then place half mold A above half mold B, and put the positioning pin with the ball head facing downward and spring B into the slot hole in sequence, and press the upper end of spring B downward with the fixing screw, so that spring B has a pre-pressure to press the positioning pin into the positioning slot;

[0055] 4) Then, insert the enlarged head of the transmission rod upwards into the flared opening, through hole A, notch and strip groove A from top to bottom, and tighten the enlarged head together with the transmission rod with the set bolts;

[0056] 5) Fix one end of the core rod to the through hole B in the end cover A or the end cover B which is provided with an interference fit with the core rod;

[0057] 6) Then, insert the other end of the core rod into the strip groove A, and then pass it through the sliding hole of the transmission rod and the spring A with spring brackets connected at both ends;

[0058] 7) Then fix the end cover A or end cover B fixed to the core rod to the half mold B by fastening screws;

[0059] 8) The remaining end cap B or end cap A is provided with a through hole B which is in clearance with the core rod and is sleeved on the other end of the core rod, and the end cap is fixed to the half mold B by fastening screws;

[0060] 9) Use external force to overcome the force of spring A to make half mold A and half mold B slide relative to each other, and the sliding distance is less than the distance between two adjacent metal atomic models; after removing the external force, if half mold A and half mold B can return to the starting position under the force of spring A, the assembly is successful; if half mold A and half mold B cannot return to the starting position under the force of spring A, it is necessary to adjust the preload of spring B by adjusting the screw-in degree of the fixing screw, and repeat this step until half mold A and half mold B can return to the starting position under the force of spring A.

[0061] In order to improve the demonstration effect, the metal atom model and the lattice line model are sprayed with a layer of paint A or fixed with a decorative layer A; the remaining surfaces are sprayed with a paint layer B or fixed with a decorative layer B, and the colors of the paint layer A and the paint layer B or the colors of the decorative layer A and the decorative layer B are contrasting colors. In addition, the openings of the bolts or screws are sealed and sprayed with a paint layer B or fixed with a decorative layer B.

[0062] The beneficial effects of the present invention are:

[0063] First, the teaching aids for demonstrating elastic deformation and plastic deformation of metal materials and the method for assembling the teaching aids can demonstrate the principles of elastic deformation and plastic deformation of metals from the microscopic perspective of the lattice.

[0064] Second, the present invention is a kind of metal material elastic deformation and plastic deformation demonstration teaching aids and assembly method thereof, using elastic-plastic deformation teaching model to carry out teaching related to elastic and plastic deformation, which can not only overcome the shortcomings of schematic teaching without change process, but also overcome the shortcomings of animation teaching without force size feeling, and it has significant advantages of being real and credible. During the teacher's demonstration or the student's operation, the size of the force, deformation and recovery process can be experienced. This objective feeling obviously helps to understand the knowledge of slip. In the field of related material science teaching, it has certain promotion value.

[0065] Third, the present invention provides a demonstration teaching aid for elastic deformation and plastic deformation of metal materials and an assembly method thereof. The teaching aid demonstrates the process of elastic deformation and plastic deformation of metal, and the demonstration effect is more specific, more vivid, and more perceptual, which is convenient for students to understand the principles of elastic deformation and plastic deformation.

[0066] Fourthly, the teaching aids for demonstrating elastic deformation and plastic deformation of metal materials and the assembly method thereof of the present invention have a sophisticated structure, are convenient for mass production, and are very convenient for disassembly and assembly of the teaching aids. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] Figure 1 Schematic diagram of the slip plane and force of the lattice.

[0068] Figure 2 Schematic diagram of the elastic deformation process of the lattice.

[0069] Figure 3 Schematic diagram of the elastic deformation + plastic deformation process of the lattice.

[0070] Figure 4 Schematic diagram of the lattice slip process.

[0071] Figure 5 It is the right side view of the starting position of the present invention.

[0072] Figure 6 It is the left view of the starting position of the present invention.

[0073] Figure 7 It is a front full sectional view of the starting position of the present invention.

[0074] Figure 8 It is the front view of the starting position of the present invention.

[0075] Fig. 9 It is a left-side full sectional view of the starting position of the present invention.

[0076] Fig.10 It is a front full cross-sectional view of the present invention when elastic deformation occurs due to external force.

[0077] Fig.11 It is a front view of the present invention when elastic deformation occurs due to external force.

[0078] Fig.12 It is a front full cross-sectional view of the present invention when plastic deformation occurs due to external force.

[0079] Fig.13 It is a front view of the present invention when it is plastically deformed by external force.

[0080] Fig.14 It is a front full cross-sectional view of the present invention when elastic deformation + plastic deformation occurs due to external force.

[0081] Fig.15 It is a front view of the present invention when elastic deformation + plastic deformation occurs due to external force. DETAILED DESCRIPTION

[0082] Combination Figure 5~Figure 15 It can be seen that a demonstration teaching aid for elastic deformation and plastic deformation of a metal material of the present invention comprises a half mold A1 and a half mold B2 that match each other, wherein the contact surfaces of the half mold A1 and the half mold B2 are slidably connected to each other, and a side end surface of the half mold A1 and a corresponding side end surface of the half mold B2 form a demonstration surface, and at least one row of metal atomic models 24 parallel to the relative movement direction of the half mold A1 and the half mold B2 are provided on the demonstration surface of the half mold A1, and at least one row of metal atomic models 24 matching the position of the metal atomic models 24 of the half mold A1 are provided on the corresponding demonstration surface of the half mold B2. Model 24, within the same demonstration surface, a lattice line model is provided between any two adjacent metal atom models 24, and the distance between any two adjacent metal atom models 24 is equal; the contact surface of the half mold A1 and the half mold B2 is located between two adjacent rows of metal atom models 24, and a reset device and a positioning device are provided between the half mold A1 and the half mold B2. The positioning device is provided with two positioning positions within the relative sliding range of the half mold A1 and the half mold B2, and the distance between the two positioning positions is equal to the spacing between the two adjacent metal atom models 24.

[0083] When the positioning device is located at any positioning position, the lattice line model of the metal atom model 24 of at least one half-mold A1 is aligned with the lattice line model of the metal atom model 24 of the half-mold B2.

[0084] When the half mold A1 moves relative to the half mold B2 in the opposite direction to the reset force of the reset device under the action of external force, the reset force generated by the reset device drives the half mold A1 to move relative to the half mold B2 to the closest positioning position.

[0085] The reset device includes a transmission rod 15 fixed to the half mold A1 and a core rod 5 fixed to the half mold B2. The core rod 5 is parallel to the direction of relative movement between the half mold A1 and the half mold B2. Both ends of the core rod 5 are fixed to the half mold B2. A preloaded spring A9 is also sleeved on the core rod 5. One end of the spring A9 is in contact with the transmission rod 15, and the other end is fixed relative to the core rod 5.

[0086] The core rod 5 is fixed in the strip groove A14 provided in the half mold B2, and the notch 18 of the strip groove A14 faces the half mold A1. The end of the transmission rod 15 away from the half mold A1 extends from the notch 18 into the strip groove A14 and connects with the core rod 5.

[0087] When the transmission rod 15 moves from one end of the slot 18 to the other end of the slot 18 along the core rod 5 , the positioning device passes through all the positioning positions.

[0088] The transmission rod 15 is provided with a sliding hole 16 matching with the core rod 5 , and the sliding hole 16 matches with the core rod 5 .

[0089] The two ends of the spring A9 are respectively fixed to the spring bracket 8 , and the two ends of the spring A9 are respectively fixed to the transmission rod 15 and the core rod 5 through the spring bracket 8 .

[0090] The end of the transmission rod 15 facing the half-mold A1 extends into the through hole A18' provided in the half-mold A1, and the end of the transmission rod 15 located in the through hole A18' is provided with an enlarged head 3, and the end of the through hole A18' facing away from the half-mold B2 is provided with a flared opening matching the enlarged head 3, the opening of the flared opening is connected to the flared opening by a fixing bolt 4, and the enlarged head 3 is fixed at the connection between the flared opening and the through hole A18', at this time, the core rod 5 matches the position of the sliding hole 16.

[0091] Both ends of the strip groove A14 pass through the half mold B2, and both ends of the core rod 5 are respectively fixed to the end cover A6 and the end cover B10 provided at both ends of the strip groove A14.

[0092] The end cover A6 and the end cover B10 are respectively provided with a through hole B, and the through holes B of the end cover A6 and the end cover B10 are respectively connected to the corresponding ends of the core rod 5, one end of the core rod 5 and the through hole B are interference fit, and the other end of the core rod 5 and the through hole B are clearance fit.

[0093] The end cover A6 and the end cover B10 are fixed to the half mold B2 by fastening screws 7 respectively.

[0094] The end surfaces of the end caps A6 and B10 facing away from the half-mold B2 are flush with the end surfaces of the corresponding sides of the half-mold B2.

[0095] There are multiple core rods 5, which are arranged parallel to each other.

[0096] The positioning device includes a positioning pin 11 arranged on the end surface of half mold A1 facing half mold B2, the end of the positioning pin 11 facing away from half mold B2 is located in a slot hole provided in half mold A1, and the end of the positioning pin 11 facing away from half mold B2 is reciprocated along the direction facing or away from half mold B2 by a spring B12, the spring B12 is provided with a pre-pressure, and the end surface of the half mold A1 facing away from the half mold B2 is provided with positioning grooves 17 matching the positioning pin 11 at the positioning position, and when the positioning pin 11 is located in any one of the positioning grooves 17, at least one lattice line model of the metal atomic model 24 of the half mold A1 is connected to the lattice line model of the metal atomic model 24 of the half mold B2.

[0097] The end of the slot hole facing away from the half-mold B2 passes through the half-mold A1 and is threadedly connected with a fixing screw 13 . One end of the spring B12 contacts the end of the fixing screw 13 .

[0098] One end of the positioning pin 11 facing the positioning groove 17 is a ball head, and the positioning groove 17 is a matching spherical arc groove.

[0099] A strip groove B19 is provided in the middle of the contact surface between the half mold B2 and the half mold A1, along the relative movement direction between the half mold A1 and the half mold B2; a matching slide bar 21 is provided in the middle of the contact surface between the half mold A1 and the half mold B2, corresponding to the strip groove B19; a limiting groove 20 parallel to the strip groove B19 is symmetrically provided on the inner side of the groove wall of the strip groove B19; a matching limiting rod 22 is provided on the side wall of the slide bar 21, corresponding to the limiting groove 20.

[0100] When the limiting rod 22 moves along the limiting groove 20 from one end to the other end of the limiting groove 20 , the positioning pin shaft 11 passes through all the positioning grooves 17 .

[0101] The limiting groove 20 passes through the side wall of the strip groove B19 corresponding to the end in the opposite direction of the pre-force of the spring A9.

[0102] A notch 23 is provided at the contact surface between the half mold A1 and the half mold B2, at one end located in the opposite direction of the pre-force of the spring A9, and the length of the notch 23 along the direction parallel to the relative movement direction of the half mold A1 and the half mold B2 is greater than or equal to the maximum stroke of the relative movement of the half mold A1 and the half mold B2.

[0103] The two opposite corresponding side end surfaces of the half mold A1 and the half mold B2 are both demonstration surfaces.

[0104] When the adjacent end faces of the half-mold A1 and the half-mold B2 are aligned, the positioning pin 11 is located in the positioning groove 17 at one end of a row of positioning positions.

[0105] When the present invention is assembled, the steps are as follows:

[0106] 1) First, place the end of the mold half A1 with the notch 23 facing away from the mold half B2, and align the slide bar 21 of the mold half A1 with the strip groove 19 of the mold half B2, and align the limit rod 22 with the limit groove 20;

[0107] 2) Then, the half mold A1 is moved relative to the half mold B2 along the direction of the limiting rod 22 and the limiting groove 21 until the adjacent end faces of the half mold A1 and the half mold B2 are aligned;

[0108] 3) Next, place the half mold A1 above the half mold B2, and place the positioning pin 11 with the ball head facing downward and the spring B12 into the slot hole in sequence, and press the upper end of the spring B12 downward by the fixing screw 13, so that the spring B12 has a pre-pressure to press the positioning pin 11 toward the positioning slot 17;

[0109] 4) Then, insert the enlarged head 3 of the transmission rod 15 upwards, from top to bottom, into the flared opening, through hole A18', notch 18 and strip groove A14 in sequence, and tighten the enlarged head 3 together with the transmission rod 15 by means of the set bolt 4;

[0110] 5) Fix one end of the core rod 5 to the through hole B in the end cover A9 or the end cover B10 which is provided with an interference fit with the core rod 5;

[0111] 6) After the other end of the core rod 5 is inserted into the strip groove A14, it passes through the sliding hole 16 of the transmission rod 15 and the spring A9 connected to the spring bracket 8 at both ends;

[0112] 7) Then, the end cap A9 or the end cap B10 fixed to the core rod 5 is fixed to the half mold B2 by fastening screws 7;

[0113] 8) The remaining end cap B10 or end cap A9 is provided with a through hole B which is loosely matched with the core rod 5 and is sleeved on the other end of the core rod 5, and the end cap is fixed to the half mold B2 by means of the fastening screws 7;

[0114] 9) Using external force to overcome the force of the spring A9, the mold halves A1 and B2 are caused to slide relative to each other, and the sliding distance is less than the distance between two adjacent metal atom models 24; after removing the external force, if the mold halves A1 and B2 can return to their starting positions under the force of the spring A9, the assembly is successful; if the mold halves A1 and B2 cannot return to their starting positions under the force of the spring A9, it is necessary to adjust the preload of the spring B12 by adjusting the degree of screwing of the fixing screw 13, and repeat this step until the mold halves A1 and B2 can return to their starting positions under the force of the spring A9.

[0115] In order to improve the demonstration effect, the metal atom model and the lattice line model are sprayed with a layer of paint A or fixed with a decorative layer A; the remaining surfaces are sprayed with a paint layer B or fixed with a decorative layer B, and the colors of the paint layer A and the paint layer B or the colors of the decorative layer A and the decorative layer B are contrasting colors. In addition, the openings of the bolts or screws are sealed and sprayed with a paint layer B or fixed with a decorative layer B.

[0116] When the present invention demonstrates the elastic deformation of metal, the teacher overcomes the action force of the spring B12 by a relatively small external force to make the positioning pin 11 leave the positioning groove 17, and overcomes the action force of the spring A9 to make the half mold A1 move relative to the half mold B2 along the direction of the limit rod 22 and the limit groove 21; when the half mold A1 moves relative to the half mold B2 to the position where the positioning pin 11 leaves the positioning groove 17 and the external force is withdrawn, at this time, the transmission rod 15 drives the half mold A1 to move in the opposite direction relative to the half mold B2 under the action of the restoring force of the spring A9, and moves in the opposite direction until the positioning pin 11 is located in the original positioning groove 17, and the positioning pin 11 is matched and positioned with the original positioning groove 17 under the action of the restoring force of the spring B12. The phenomenon displayed on the demonstration surface of the present invention in this process is: under the action of a smaller external force, the metal atoms of the metal crystal will deviate from their equilibrium position and be in a non-equilibrium position. The metal atoms deviating from the equilibrium position are affected by the repulsive force or attractive force generated by the surrounding metal atoms. This effect is equivalent to an elastic force, which has a high elastic potential energy and is an unstable state, tending to shift to a low energy state (equilibrium state); therefore, when the smaller external force is removed, under the action of the elastic force between the surrounding metal atoms and the metal atoms deviating from the equilibrium position, the metal atoms deviating from the equilibrium position return to the original equilibrium position, that is, they return from a high energy state to a lowest energy state, forming elastic deformation.

[0117] When the present invention demonstrates the plastic deformation caused by metal sliding, the teacher overcomes the action force of the spring B12 by a large external force to make the positioning pin 11 leave the positioning groove 17, and overcomes the action force of the spring A9 to make the half mold A1 move relative to the half mold B2 along the direction of the limit rod 22 and the limit groove 21; when the half mold A1 moves relative to the half mold B2 until the positioning pin 11 leaves the positioning groove 17 and moves to the position away from other positioning grooves 17, the large external force is removed. At this time, the transmission rod 15 drives the half mold A1 to move in the opposite direction relative to the half mold B2 under the action of the restoring force of the spring A9, and moves in the opposite direction until the positioning pin 11 is located in the closest positioning groove 17. Under the action of the restoring force of the spring B12, the positioning pin 11 is matched and positioned with the adjacent positioning groove 17. The phenomenon displayed on the demonstration surface of the present invention in this process is: when a metal crystal is subjected to a large external force, when the external force exceeds a certain value, the distance moved by the atoms will be greater than an atomic equilibrium distance, and the atoms that deviate from the equilibrium position can no longer return to the original equilibrium position, but can only return to the equilibrium position that has been crossed. The atoms in this equilibrium position also have the lowest energy state, and can therefore exist permanently, forming plastic deformation.

Claims

1. A demonstration teaching aid for elastic deformation and plastic deformation of metal materials, characterized by: The invention comprises a half mold A (1) and a half mold B (2) which match each other, wherein the contact surfaces of the half mold A (1) and the half mold B (2) are slidably connected to each other, and a side end surface of the half mold A (1) and a corresponding side end surface of the half mold B (2) form a demonstration surface. The demonstration surface of the half mold A (1) is provided with at least one row of metal atomic models (24) which are parallel to the relative movement direction of the half mold A (1) and the half mold B (2), and the corresponding demonstration surface of the half mold B (2) is provided with at least one row of metal atomic models (24) which match the position of the metal atomic models (24) of the half mold A (1). Within the same demonstration surface, A lattice line model is provided between any two adjacent metal atomic models (24), and the distance between any two adjacent metal atomic models (24) is equal; a contact surface between the half mold A (1) and the half mold B (2) is located between two adjacent rows of metal atomic models (24); a reset device and a positioning device are provided between the half mold A (1) and the half mold B (2); the positioning device is provided with a plurality of positioning positions within a relative sliding range of the half mold A (1) and the half mold B (2); and the distance between two adjacent positioning positions is equal to the spacing between two adjacent metal atomic models (24); When the positioning device is located at any positioning position, the lattice line model of the metal atom model (24) of at least one half mold A (1) is aligned with the lattice line model of the metal atom model (24) of the half mold B (2); When the mold half A (1) moves relative to the mold half B (2) in a direction opposite to the resetting force of the resetting device under the action of an external force, the resetting force generated by the resetting device drives the mold half A (1) to move relative to the mold half B (2) to the closest positioning position; The reset device comprises a transmission rod (15) fixed to the half mold A (1) and a core rod (5) fixed to the half mold B (2), the core rod (5) being parallel to the direction of relative movement of the half mold A (1) and the half mold B (2), both ends of the core rod (5) being fixed to the half mold B (2), a preloaded spring A (9) being sleeved on the core rod (5), one end of the spring A (9) being in contact with the transmission rod (15) and the other end being fixed relative to the core rod (5); The core rod (5) is fixed in a strip groove A (14) provided in the half mold B (2), the notch (18) of the strip groove A (14) faces the half mold A (1), and the end of the transmission rod (15) away from the half mold A (1) extends from the notch (18) into the strip groove A (14) to connect with the core rod (5); The positioning device comprises a positioning pin (11) provided on the end surface of the half mold A (1) facing the half mold B (2), one end of the positioning pin (11) facing away from the half mold B (2) is located in a slot provided in the half mold A (1), and the end of the positioning pin (11) facing away from the half mold B (2) is reciprocated in a direction facing or away from the half mold B (2) by a spring B (12), the spring B (12) is provided with a pre-pressure, and positioning grooves (17) matching the positioning pin (11) are respectively provided at the positioning position on the end surface of the half mold B (2) facing away from the half mold A (1), and when the positioning pin (11) is located in any one of the positioning grooves (17), at least one lattice line model of the metal atomic model (24) of the half mold A (1) is connected to the lattice line model of the metal atomic model (24) of the half mold B (2).

2. A teaching aid for demonstrating elastic deformation and plastic deformation of metal materials as claimed in claim 1, characterized in that: When the transmission rod (15) moves from one end of the slot (18) to the other end of the slot (18) along the core rod (5), the positioning device passes through all positioning positions.

3. A teaching aid for demonstrating elastic deformation and plastic deformation of metal materials as claimed in claim 1, characterized in that: One end of the slotted hole facing away from the half-mold B (2) passes through the half-mold A (1) and is threadedly connected to a fixing screw (13), and one end of the spring B (12) contacts the end of the fixing screw (13).

4. A teaching aid for demonstrating elastic deformation and plastic deformation of metal materials as claimed in claim 1, characterized in that: One end of the positioning pin (11) facing the positioning groove (17) is a ball head, and the positioning groove (17) is a matching spherical arc surface groove.

5. A teaching aid for demonstrating elastic deformation and plastic deformation of metal materials as claimed in claim 1, characterized in that: A strip groove B (19) is provided in the middle of the contact surface between the half mold B (2) and the half mold A (1) and along the relative movement direction between the half mold A (1) and the half mold B (2); a matching slide bar (21) is provided in the middle of the contact surface between the half mold A (1) and the half mold B (2) and corresponding to the strip groove B (19); a limiting groove (20) parallel to the strip groove B (19) is symmetrically provided on the inner side of the groove wall of the strip groove B (19); and a matching limiting rod (22) is provided on the side wall of the slide bar (21) and corresponding to the limiting groove (20).

6. A teaching aid for demonstrating elastic deformation and plastic deformation of metal materials as claimed in claim 1, characterized in that: A notch (23) is provided at one end of the contact surface between the half mold A (1) and the half mold B (2) and located in the opposite direction of the pre-load force of the spring A (9), and the length of the notch (23) along the direction parallel to the relative movement of the half mold A (1) and the half mold B (2) is greater than or equal to the maximum stroke of the relative movement of the half mold A (1) and the half mold B (2).

7. A method for assembling a demonstration teaching aid according to any one of claims 1 to 6, characterized in that The following steps are involved: 1) First, place the end of the half mold A (1) provided with the notch (23) away from the half mold B (2), and align the slide bar (21) of the half mold A (1) with the strip groove (19) of the half mold B (2), and at the same time align the limit rod (22) with the limit groove (20); 2) Then, the half mold A (1) is moved relative to the half mold B (2) along the direction of the limiting rod (22) and the limiting groove (21) until the adjacent end faces of the half mold A (1) and the half mold B (2) are aligned; 3) Next, half mold A (1) is placed above half mold B (2), and the positioning pin (11) with the ball head facing downward and the spring B (12) are sequentially placed into the slotted hole, and the upper end of the spring B (12) is pressed downward by the fixing screw (13), so that the spring B (12) has a pre-pressure to press the positioning pin (11) toward the positioning slot (17); 4) Then, the enlarged head (3) of the transmission rod (15) is inserted into the flared opening, the through hole A (18'), the notch (18) and the strip groove A (14) in order from top to bottom with the enlarged head (3) facing upward, and the enlarged head (3) and the transmission rod (15) are pressed and fixed together by the fixing bolts (4); 5) fixing one end of the core rod (5) to a through hole B in the end cover A (9) or the end cover B (10) which is provided with an interference fit with the core rod (5); 6) After the other end of the core rod (5) is inserted into the strip groove A (14), it passes through the sliding hole (16) of the transmission rod (15) and the spring A (9) connected to the spring bracket (8) at both ends; 7) Then, the end cover A (9) or the end cover B (10) fixed to the core rod (5) is fixed to the half mold B (2) by tightening the screws (7); 8) A through hole B having a clearance fit with the core rod (5) is provided in the remaining end cover B (10) or the end cover A (9), which is placed on the other end of the core rod (5), and the end cover is fixed to the half mold B (2) by means of a fixing screw (7); 9) Using external force to overcome the force of the spring A (9), the mold halves A (1) and B (2) are caused to slide relative to each other, and the sliding distance is smaller than the distance between two adjacent metal atom models (24); after the external force is removed, if the mold halves A (1) and B (2) can return to their starting positions under the force of the spring A (9), the assembly is successful; if the mold halves A (1) and B (2) cannot return to their starting positions under the force of the spring A (9), the preload of the spring B (12) needs to be adjusted by adjusting the screwing degree of the fixing screw (13), and the step is repeated until the mold halves A (1) and B (2) can return to their starting positions under the force of the spring A (9).

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