In-situ heating pasty zone high-temperature mechanical property testing device

Abstract

The invention discloses an in-situ heating pasty zone high-temperature mechanical property testing device. The device comprises a stretching device, a left furnace door, a furnace body, a connecting rod, a left water-cooling chuck, a micro-displacement sensor, a test bar, a thermocouple, an induction coil, a ceramic crucible, a heat preservation layer, a right water-cooling chuck, a rigid beam, a bearing beam, a right furnace door, a stress sensor, a vacuum device and a stretching device guide rail support. Under the high vacuum condition, the water flow of a water cooling chuck and the temperature of an induction coil are adjusted, the test bar is cooled to the set paste area temperature after being heated and melted, a stretching device is started, the stretching rate is controlled, and the high-temperature mechanical properties of the metal test bar at different temperatures, cooling rates and stretching rates are measured; the problem that a traditional mechanical property testing device cannot test the mechanical property of the metal when the metal is cooled to a pasty area after being heated or melted is solved, and the mechanical property data of the pasty areas of different metals are filled. The device can quantitatively and accurately test the high-temperature mechanical properties of the pasty zone of the metal under different conditions.

Description

Technical Field

[0001] The invention relates to the technical field of mechanical properties of materials under high temperature conditions, in particular to an in-situ heated pasty zone high temperature mechanical properties testing device. Background Art

[0002] The background of high temperature mechanical properties testing equipment mainly comes from the needs of materials science and engineering. In many industrial applications, such as aerospace, energy and automotive manufacturing, the performance of materials in high temperature environments is crucial. The mechanical properties of traditional materials may drop significantly at high temperatures, especially in the semi-solid range (paste zone), where the material performance drop is more obvious, so understanding and testing these properties is crucial for material selection and application.

[0003] With the advancement of technology, many new materials (such as super alloys, ceramic composites, etc.) have been developed to meet the use requirements in high temperature environments and are widely used in various fields. Under high temperature environments, the mechanical properties of materials such as strength, toughness, fatigue and creep may be affected, so special testing equipment is required to evaluate these properties. Many international standards (such as ASTM, ISO, etc.) have formulated methods and equipment requirements for high temperature mechanical properties testing to ensure the reliability and comparability of test results.

[0004] At present, the test methods for measuring the high temperature mechanical properties of metals are:

[0005] 1. Use a high temperature tensile testing machine to measure the tensile properties, yield strength and ductility of materials under high temperature conditions. This can be achieved through a heating furnace and a high temperature fixture.

[0006] 2. Use a high temperature fatigue testing machine to evaluate the fatigue life of materials under repeated loading conditions under high temperature conditions, and to study the fatigue life and fatigue resistance of materials. It is usually equipped with a high temperature furnace and a data acquisition system.

[0007] 3. Use creep test equipment to detect the deformation characteristics of materials under long-term high temperature and constant load, usually used to evaluate the creep rate and limit of materials. Creep testing usually requires strict temperature control and high-precision measurement systems.

[0008] 4. Using a thermomechanical analyzer (TMA), the thermal expansion and other mechanical properties of materials can be measured at high temperatures, and is suitable for materials such as ceramics and polymers.

[0009] 5. Digital image correlation (DIC) technology is used to analyze the deformation of the material surface image. Combined with high temperature testing, it can monitor the deformation and crack development of the material in real time, thereby improving the accuracy and information content of the test.

[0010] Almost none of the above technologies or equipment considers the mechanical property test of metal when it is heated or cooled to a semi-solid state (also known as a mushy zone), so it is difficult to test the high-temperature mechanical properties of metal in this temperature range, resulting in almost complete blank data. Moreover, high-temperature testing usually requires a long preheating and stabilization time, which will cause significant changes in the properties of the mushy zone, thereby deviating from the actual mechanical properties of the mushy zone during the actual solidification process. At the same time, high-temperature testing has high requirements for sample preparation, and the size and shape of the sample need to be strictly controlled. Summary of the invention

[0011] The purpose of the present invention is to provide an in-situ heated mushy zone high temperature mechanical properties testing device, which adopts the method of in-situ heating of metal, takes into account the testing method of mechanical properties when the metal is heated or cooled to a semi-solid state (also known as a mushy zone), and tests the high temperature mechanical properties of the metal under different conditions by changing the temperature, stress, stretching rate and cooling rate of the test rod under high temperature conditions, thereby having good stability and high measurement accuracy.

[0012] To achieve the above object, the present invention provides the following solutions:

[0013] An in-situ heated pasty zone high temperature mechanical property testing device, comprising:

[0014] Stretching device, left furnace door, furnace body, connecting rod, left water-cooling chuck, micro-displacement sensor, test rod, thermocouple, induction coil, insulation layer, ceramic crucible, right water-cooling chuck, rigid beam, load-bearing beam, right furnace door, stress sensor, vacuum device, guide rail bracket of stretching device;

[0015] The stretching device is arranged on the outer left side of the furnace body for stretching the test rod; the left furnace door and the right furnace door are arranged on both sides of the furnace body for closing the furnace body; the left water-cooling chuck, the right water-cooling chuck, the test rod, the ceramic crucible, the thermocouple, the induction coil, the insulation layer, the micro-displacement sensor, and the stress sensor are arranged in the furnace cavity of the furnace body; the vacuum device is arranged at the bottom of the furnace body and communicates with the inside of the furnace body; the lower end of the stretching device is equipped with the stretching device guide rail bracket, which can move left and right on the stretching device guide rail bracket and lock at any position of the sliding range; the micro-displacement sensor is arranged inside the left water-cooling chuck, and the other end is connected to the test rod. The micro-displacement sensor is used to synchronously measure the test rod in the high temperature range due to The displacement caused by thermal expansion; the stress sensor is arranged beside the right furnace door in the furnace body and fixed on the right furnace door, the stress sensor is threadedly connected to one end of the right water-cooling chuck, and the other end of the right water-cooling chuck is threadedly connected to the test rod, and the stress sensor is used to synchronously measure the external force applied by the stretching device; the stretching device, the micro-displacement sensor, the stress sensor and the coaxiality of the test rod; the left water-cooling chuck and the right water-cooling chuck are fixed to the left and right ends of the test rod by threaded connection, which are used to accurately control the size of the water flow and control the speed of axial heat dissipation of the test rod during the cooling process; the load-bearing beam is arranged on the outside of the furnace body, connected to the left furnace door and the right furnace door, and is used to apply the force applied to the stress sensor to the load-bearing beam;

[0016] The ceramic crucible is a hollow cylinder, the inner diameter of which is equal to the diameter of the test rod, and the test rod is arranged in the hollow cylinder and is coaxial with the ceramic crucible; the outer side of the ceramic crucible is covered with the insulation layer, and the outer side of the insulation layer is the induction coil, and the induction coil is used to heat the test rod wrapped by the induction coil by resistance after passing current; the thermocouple is pre-buried on the outer wall of the ceramic crucible, and is used to synchronously measure the temperature of the test rod;

[0017] The vacuum device is started, and after being drawn to a high vacuum state, the heating power is adjusted to heat the test rod to above the liquidus line, and the test rod is cooled to the target temperature of the mushy zone at a certain cooling rate, and the water flow of the left water-cooled chuck and the right water-cooled chuck is controlled to control the stretching rate of the stretching device. After the stretching device is started, the test rod is stretched at a certain cooling rate and stretching rate during the cooling process of the test rod, and the high-temperature mechanical properties of the metal test rod in the mushy zone can be measured in a relatively short time, avoiding the influence of dendrite coarsening on the mechanical properties test of the mushy zone. In addition, by selecting different temperatures, cooling rates, and stretching rates to stretch the test rod, the high-temperature mechanical properties of the metal test rod under different conditions can also be measured. This invention can quantitatively and accurately test the high-temperature mechanical properties of the metal in the mushy zone.

[0018] Optionally, the stretching device is fixed to one end of the connecting rod, and the other end of the connecting rod is connected to the left water-cooling chuck; the stretching device is used to actively load external force, apply external force during the heating, cooling and insulation process of the test rod, control the stretching rate of the test rod during the loading process, and measure the high-temperature mechanical properties of the test rod.

[0019] Optionally, the left water-cooling chuck and the right water-cooling chuck are both composed of a fixture and a cooling water channel, and the cooling water channel is installed on the fixture; the left water-cooling chuck and the right water-cooling chuck are connected to a circulating water cooler, which is used to control the speed of heat dissipation of the test rod during the cooling process, control the cooling rate of the test rod, and measure the high-temperature mechanical properties of the metal test rod at different cooling rates.

[0020] Optionally, the in-situ heated pasty zone high-temperature mechanical properties testing device also includes a rigid beam, which is horizontally welded to the right furnace door and threadedly connected to the right water-cooled chuck to fix the chuck and ensure that the test rod is clamped horizontally.

[0021] Optionally, the load-bearing beam is a rigid connecting rod, which is arranged on the outside of the furnace body and connects the left furnace door and the right furnace door, and is used to apply the force applied to the stress sensor to the load-bearing beam, forming a force frame with the furnace body base, so that the interior of the furnace body is no longer subjected to force, so that the vacuum chamber formed inside the furnace body is not affected by the external force applied by the stretching device, which is used to avoid errors caused by the deformation of the vacuum shell and the sealing rubber ring due to force, and reduce the influence of vacuum degree on the measurement of high-temperature mechanical properties.

[0022] Optionally, the micro-displacement sensor is arranged inside the left water-cooling chuck and the other end is connected to the test rod. The micro-displacement sensor is used to synchronously measure the displacement caused by thermal expansion when the test rod is heated or cooled to a semi-solid state (also called a mushy zone). By controlling the displacement of the test rod, the error of the mechanical properties of the mushy zone caused by thermal expansion is offset, thereby improving the accuracy of the high-temperature mechanical properties test of the mushy zone.

[0023] Optionally, the ceramic crucible is a hollow cylinder, the inner diameter of the hollow cylinder is equal to the diameter of the test rod, and the test rod is arranged in the hollow cylinder and coaxial with the ceramic crucible; when the test rod is heated or cooled to a semi-solid state (also called a pasty zone), the ceramic crucible has excellent high temperature resistance, chemical stability and low thermal expansion, so it can play a protective role for the test rod in the semi-solid state to ensure that there will be no leakage, so that the in-situ heated pasty zone high temperature mechanical properties testing device can measure the mechanical properties of the test rod in the high temperature pasty zone.

[0024] Optionally, the ceramic crucible is covered with the thermal insulation layer on the outside, and the thermal insulation layer is covered with the induction coil on the outside. The induction coil is used to generate resistance heat after current is passed through it, so that the part of the test rod wrapped by the induction coil melts, and a uniform high-temperature zone is formed in this part of the test rod; the left water-cooling chuck and the right water-cooling chuck are fixed at the left and right ends of the test rod, so that a low-temperature zone is formed except for the part wrapped by the induction coil, thereby producing a high temperature gradient area.

[0025] Optionally, the in-situ heated mushy zone high temperature mechanical properties testing device is designed with two sample preparation schemes that can form a high temperature gradient area. One of them is to reduce the diameter of the sample of the tested section to form a dog-bone-shaped sample, which is conducive to the formation of a uniform temperature zone in the tested section; the other is to adjust the thickness distribution of the insulation layer so that the insulation layer in the center of the tested section is thinner and thicker at both ends, which is also conducive to the formation of a uniform temperature zone in the tested section. These two methods take advantage of the fact that the performance of the mushy zone is significantly lower than that of the solid phase zone. The tested section is in a uniform temperature mushy zone and has a high temperature gradient on both sides, which can evenly apply tension to the tested section without causing obvious deformation of other parts. Therefore, the high temperature mechanical properties of the mushy zone can be tested more accurately.

[0026] Optionally, the in-situ heated pasty zone high-temperature mechanical properties testing device also includes a data signal acquisition control system, which is used to convert the temperature, stress, stretching rate and cooling rate obtained by the thermocouple, the stress sensor, the stretching device, the left water-cooled chuck and the right water-cooled chuck into data signals and collect and store them throughout the process; the acquisition frequency of the data signal control acquisition system is 1Hz-100Hz.

[0027] Optionally, the maximum heating temperature of the in-situ heated paste zone high temperature mechanical properties test device is 2000°C; the range of the heating and cooling rate is 0.01-100K / s; the temperature control error of the heating and cooling is less than ±2k; the cold limit vacuum of the in-situ heated paste zone high temperature mechanical properties test device is 6.67×10 -3 Pa.

[0028] Optionally, the maximum heating temperature of the in-situ heated paste zone high temperature mechanical properties test device is 2000°C; the range of the heating and cooling rate is 0.01-100K / s; the temperature control error of the heating and cooling is less than ±1k; the cold limit vacuum of the in-situ heated paste zone high temperature mechanical properties test device is 1.5×10 -3 Pa.

[0029] Optionally, the maximum test force of the stretching device is 20kN; the stretching rate range is 0.001-3mm / s; and the effective stretching range is 50mm.

[0030] Optionally, the stress sensor has a measuring range of 2KN, 5kN, 10kN and 20kN, is replaceable, and has an error of ≤0.5%.

[0031] Optionally, the cooling water flow rate of the water-cooled chuck is 0.5L / min-10L / min.

[0032] Optionally, the frequency of the current passed through the induction coil is 10kHz-30kHz.

[0033] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0034] The present invention provides a high-temperature mechanical property testing device for the mushy zone with in-situ heating, which avoids the inconvenience caused by the molten casting method through in-situ induction heating. The sample is heated by induction, and the cooling rate of the sample can be controlled; the experiment is in a high vacuum environment, which further improves the accuracy of the measurement; the influence of the electric current heating sample on the plasticity and strength of the metal is avoided, and the tensile rate, temperature and stress of the sample can be controlled, and the test method of the mechanical properties of the metal when it is heated or cooled to a semi-solid state (also known as the mushy zone) is considered, so that the high-temperature mechanical properties of the mushy zone of the metal under different conditions can be accurately measured and studied; the addition of a thermal insulation layer, in addition to being able to insulate and protect other devices in the furnace body, can also effectively reduce the axial heat transfer of the induction coil, thereby limiting the length of the molten part of the test rod, and at the same time, two sample preparation schemes that can form a high temperature gradient area are designed, which can more accurately test the high-temperature mechanical properties of the mushy zone. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0036] Figure 1 It is a schematic structural diagram of the in-situ heated pasty zone high temperature mechanical properties testing device of the present invention.

[0037] Among them, the numbers in the figure are: stretching device 1, left furnace door 2, furnace body 3, connecting rod 4, left water-cooling chuck 5, micro-displacement sensor 6, test rod 7, thermocouple 8, induction coil 9, insulation layer 10, ceramic crucible 11, right water-cooling chuck 12, rigid beam 13, load-bearing beam 14, right furnace door 15, stress sensor 16, vacuum device 17, stretching device guide rail bracket 18.

[0038] Figure 2 , Figure 3This is a schematic structural diagram of sample preparation for the in-situ heated pasty zone high temperature mechanical properties testing device of the present invention.

[0039] in, Figure 2 and Figure 3 The reference numbers are: test rod 7, thermocouple 8, induction coil 9, insulation layer 10, ceramic crucible 11.

[0040] Figure 4 , Figure 5 This is an example diagram of the test tensile curve of the in-situ heated pasty zone high temperature mechanical properties testing device of the present invention and the fracture morphology of the sample.

[0041] in, Figure 4 (a) is the stress-temperature curve of 24Mn steel at different cooling rates; Figure 4 (b) is the fracture microstructure of the sample with a cooling rate of 0.9℃ / s; Figure 4 (c) is the fracture microstructure of the sample with a cooling rate of 1.5℃ / s.

[0042] in, Figure 5 (a) is the stress-temperature curve of T10 high manganese steel at a tensile rate of 1 mm / min; Figure 5 (b) is the macroscopic fracture morphology of the sample with a tensile rate of 0.25 mm / min; Figure 5 (c) is the macroscopic fracture morphology of the sample with a tensile rate of 0.5 mm / min. DETAILED DESCRIPTION

[0043] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] The purpose of the present invention is to provide an in-situ heated mushy zone high temperature mechanical properties testing device, which adopts the method of in-situ heating of metal to control the cooling rate, stretching rate, temperature and stress of the sample, and takes into account the testing method of mechanical properties when the metal is heated or cooled to a semi-solid state (also known as a mushy zone), so as to accurately measure the high temperature mechanical properties of the metal under different conditions. The device has good stability and high measurement accuracy.

[0045] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0046] Figure 1 It is a schematic structural diagram of the in-situ heated pasty zone high temperature mechanical properties testing device of the present invention.

[0047] like Figure 1 As shown, an in-situ heated pasty zone high temperature mechanical property testing device comprises:

[0048] Stretching device 1, left furnace door 2, furnace body 3, connecting rod 4, left water-cooling chuck 5, micro-displacement sensor 6, test rod 7, thermocouple 8, induction coil 9, insulation layer 10, ceramic crucible 11, right water-cooling chuck 12, rigid beam 13, load-bearing beam 14, right furnace door 15, stress sensor 16, vacuum device 17, stretching device guide rail bracket 18;

[0049] The stretching device 1 is arranged on the outer left side of the furnace body 3 and is used to stretch the test rod 7; the left furnace door 2 and the right furnace door 15 are arranged on both sides of the furnace body 3 and are used to close the furnace body; the left water-cooling chuck 5, the right water-cooling chuck 12, the test rod 7, the ceramic crucible 11, the thermocouple 8, the induction coil 9, the insulation layer 10, the micro-displacement sensor 6, and the stress sensor 16 are arranged in the furnace cavity of the furnace body 3; the vacuum device 17 is arranged at the outer bottom of the furnace body 3 and is connected to the inside of the furnace body; the lower end of the stretching device 1 is equipped with the stretching device guide rail bracket 18, which can move left and right on the stretching device guide rail bracket 18 and lock at any position of the slide; the micro-displacement sensor 6 is arranged inside the left water-cooling chuck 5, and the other end is connected to the test rod 7. The micro-displacement sensor 6 is used to synchronously measure the test rod 7 in the high temperature range due to heat The displacement caused by expansion; the stress sensor 16 is arranged beside the right furnace door 15 in the furnace body 3 and fixed on the right furnace door 15, the stress sensor 16 is threadedly connected to one end of the right water-cooling chuck 12, and the other end of the right water-cooling chuck 12 is threadedly connected to the test rod 7, and the stress sensor 16 is used to synchronously measure the external force applied by the stretching device 1; the stretching device 1, the micro-displacement sensor 6, the stress sensor 16 and the coaxiality of the test rod 7; the left water-cooling chuck 5 and the right water-cooling chuck 12 are fixed to the left and right ends of the test rod 7 by threaded connection, which are used to accurately control the size of the water flow and control the speed of axial heat dissipation of the test rod 7 during the cooling process; the load-bearing beam 14 is arranged on the outside of the furnace body 3, connected to the left furnace door 2 and the right furnace door 15, and is used to apply the force applied to the stress sensor 16 to the load-bearing beam 14;

[0050] The ceramic crucible 11 is a hollow cylinder, the inner diameter of which is equal to the diameter of the test rod, and the test rod 7 is arranged in the hollow cylinder and is coaxial with the ceramic crucible 11; the outer side of the ceramic crucible 11 is covered with the insulation layer 10, and the outer side of the insulation layer 10 is covered with the induction coil 9, and the induction coil 9 is used to heat the test rod wrapped by the induction coil 9 by resistance after the current is passed; the thermocouple 8 is pre-buried on the outer wall of the ceramic crucible 11, and is used to synchronously measure the temperature of the test rod;

[0051] The vacuum device 17 is started, and after being drawn to a high vacuum state, the heating power is adjusted to heat the test rod 7 to above the liquidus line, and the test rod 7 is cooled to the target temperature of the mushy zone at a certain cooling rate, and the water flow of the left water-cooled chuck 5 and the right water-cooled chuck 12 is controlled to control the stretching rate of the stretching device 1. After the stretching device 1 is started, the test rod 7 is stretched at a certain cooling rate and stretching rate during the cooling process of the test rod 7, which can measure the high-temperature mechanical properties of the metal test rod in the mushy zone in a relatively short time, and avoid the influence of dendrite coarsening on the mechanical property test of the mushy zone. In addition, by selecting different temperatures, cooling rates, and stretching rates for stretching the test rod, the high-temperature mechanical properties of the metal test rod under different conditions can also be measured. This invention can quantitatively and accurately test the high-temperature mechanical properties of the metal in the mushy zone.

[0052] The stretching device 1 is fixed to one end of the connecting rod 4, and the other end of the connecting rod 4 is connected to the left water-cooling chuck 5; the stretching device 1 is used to actively load external force, apply external force during the heating, cooling and insulation process of the test rod 7, control the stretching rate of the test rod 7 during the loading process, and measure the high-temperature mechanical properties of the test rod 7.

[0053] The left water-cooling chuck 5 and the right water-cooling chuck 12 are both composed of a fixture and a cooling water channel, and the cooling water channel is installed on the fixture; the left water-cooling chuck 5 and the right water-cooling chuck 12 are connected to a circulating water cooler, which is used to control the speed of heat dissipation of the test rod 7 during the cooling process, control the cooling rate of the test rod 7, and measure the high-temperature mechanical properties of the metal test rod at different cooling rates.

[0054] The in-situ heated pasty zone high temperature mechanical properties testing device also includes a rigid beam 13, which is horizontally welded to the right furnace door and threadedly connected to the right water-cooled chuck 12 to fix the chuck and ensure the level of the test rod clamping.

[0055] The in-situ heated pasty zone high temperature mechanical properties testing device also includes a rigid beam 13, which is horizontally welded to the right furnace door 15 and threadedly connected to the right water-cooled chuck 12 for fixing the chuck to ensure that the test rod 7 is clamped horizontally.

[0056] The load-bearing beam 14 is a rigid connecting rod, which is arranged on the outside of the furnace body 3 and connects the left furnace door 2 and the right furnace door 15. It is used to apply the force applied to the stress sensor 16 to the load-bearing beam 14, and form a force frame with the furnace body base, so that the inside of the furnace body 3 is no longer subjected to force, so that the vacuum chamber formed inside the furnace body 3 is not subjected to the external force applied by the stretching device 1, and is used to avoid errors caused by the deformation of the vacuum shell and the sealing rubber ring due to force, and reduce the influence of the vacuum degree on the measurement of high-temperature mechanical properties.

[0057] The micro-displacement sensor 6 is arranged inside the left water-cooling chuck 5, and the other end is connected to the test rod 7. The micro-displacement sensor 6 is used to synchronously measure the displacement caused by thermal expansion when the test rod 7 is heated or cooled to a semi-solid state (also called a pasty zone). By controlling the displacement of the test rod 7, the error of the mechanical properties of the pasty zone caused by thermal expansion is offset, thereby improving the accuracy of the high-temperature mechanical properties test of the pasty zone.

[0058] The ceramic crucible 11 is a hollow cylinder, the inner diameter of which is equal to the diameter of the test rod, and the test rod 7 is disposed in the hollow cylinder and is coaxial with the ceramic crucible 11; when the test rod 7 is heated or cooled to a semi-solid state (also called a paste-like zone), the ceramic crucible 11 has good high temperature resistance, chemical stability and low thermal expansion, and can play a protective role for the test rod in the semi-solid state, ensuring that there will be no leakage, so that the in-situ heating high-temperature mechanical properties testing device can measure the mechanical properties of the test rod 7 in the high-temperature paste-like zone.

[0059] The ceramic crucible 11 is sheathed with the insulation layer 10, and the insulation layer 10 is coated with the induction coil 9. After the current is passed through the induction coil 9, the resistance heating is adopted to melt the part of the test rod wrapped by the induction coil 9, and a uniform high-temperature zone is formed in this part of the test rod 7; the left water-cooling chuck 5 and the right water-cooling chuck 12 are fixed to the left and right ends of the test rod 7, so that a low-temperature zone is formed in the test rod 7 except for the part wrapped by the induction coil, thereby generating a high temperature gradient zone; the in-situ heated pasty zone high-temperature mechanical properties testing device is designed with two sample preparation schemes that can form a high temperature gradient zone at the same time, and a higher temperature gradient can more accurately test the high-temperature mechanical properties.

[0060] The in-situ heated pasty zone high temperature mechanical properties testing device also includes a data signal acquisition control system, which is used to convert the temperature, stress, stretching rate and cooling rate obtained by the thermocouple 8, the stress sensor 16, the stretching device 1, the left water-cooled chuck 5 and the right water-cooled chuck 12 into data signals and collect and store them throughout the process; the acquisition frequency of the data signal control acquisition system is 100 Hz.

[0061] The maximum heating temperature of the in-situ heated paste zone high temperature mechanical properties test device is 2000°C; the range of heating and cooling rate is 0.01-100K / s; the temperature control error of heating and cooling is less than ±1k; the cold limit vacuum degree of the in-situ heated paste zone high temperature mechanical properties test device is 1.5×10 -3 Pa.

[0062] The maximum test force of the stretching device 1 is 20 kN; the stretching rate range is 0.001-3 mm / s; and the effective stretching range is 50 mm.

[0063] The stress sensor 16 has a measuring range of 2KN, 5kN, 10kN and 20kN, is replaceable, and has an error of ≤0.5%.

[0064] The cooling water flow rate of the water-cooled chucks 5 and 12 is 0.5 L / min-10 L / min.

[0065] The frequency of the current flowing into the induction coil 9 is 10 kHz-30 kHz.

[0066] Figure 2 , Figure 3 This is a schematic structural diagram of sample preparation for the in-situ heated pasty zone high temperature mechanical properties testing device of the present invention.

[0067] like Figure 2 As shown, an in-situ heated pasty zone high temperature mechanical property testing device comprises:

[0068] Test rod 7, thermocouple 8, induction coil 9, thermal insulation layer 10, ceramic crucible 11;

[0069] The test rod 7 is a cylindrical test rod, and the outer layer of the test rod 7 is covered with the ceramic crucible 11; the ceramic crucible 11 is a hollow cylinder, the inner diameter of the hollow cylinder is equal to the diameter of the test rod, and is coaxial with the test rod 7; the outer side of the ceramic crucible 11 is covered with the insulation layer 10, and the outer side of the insulation layer 10 is covered with the induction coil 9, and the induction coil 9 is used to heat the test rod wrapped by the induction coil 9 by resistance after the current is passed; the thermocouple 8 is pre-buried on the outer wall of the ceramic crucible 11, and is used to synchronously measure the temperature of the test rod;

[0070] After the current is passed through the induction coil 9, resistance heating is adopted to melt the part of the test rod wrapped by the induction coil 9, and a uniform high-temperature zone is formed in this part of the test rod 7; the left water-cooling chuck and the right water-cooling chuck are fixed at the left and right ends of the test rod 7, so that a low-temperature zone is formed in the test rod except for the part wrapped by the induction coil, thereby generating a high temperature gradient zone; the thermal insulation layer is prepared into a shape of "high on both sides and low in the middle", so that the temperature difference between the low-temperature zone at both ends of the test rod and the high-temperature zone of the part wrapped by the induction coil becomes larger, forming a higher temperature gradient, and a higher temperature gradient zone is conducive to accurately testing high-temperature mechanical properties.

[0071] like Figure 3 As shown, an in-situ heated pasty zone high temperature mechanical property testing device comprises:

[0072] Test rod 7, thermocouple 8, induction coil 9, insulation layer 10, ceramic crucible 115;

[0073] The test rod is a cylindrical test rod, and the outer layer of the test rod is covered with the ceramic crucible; the ceramic crucible is a hollow cylinder, the inner diameter of the hollow cylinder is equal to the diameter of the test rod, and is coaxial with the test rod; the outer side of the ceramic crucible is covered with the insulation layer, and the outer side of the insulation layer is covered with the induction coil, and the induction coil is used to heat the test rod by resistance after passing current, so as to melt the part of the test rod wrapped by the induction coil; the thermocouple is pre-buried on the outer wall of the ceramic crucible, and is used to synchronously measure the temperature of the test rod;

[0074] After the current is passed through the induction coil, resistance heating is used to melt the part of the test rod wrapped by the induction coil, and a uniform high-temperature zone is formed in this part of the test rod; the left water-cooling chuck and the right water-cooling chuck are fixed to the left and right ends of the test rod, so that the test rod 7 forms a low-temperature zone except for the part wrapped by the induction coil, thereby generating a high temperature gradient area; the diameter of the part of the test rod 7 wrapped by the induction coil 9 is relatively small and is prepared into a "dog bone" shape. During the stretching process, the strain is concentrated on the part with a smaller diameter, so that the melting zone length of the test rod 7 in the high-temperature range is determined as the part with a smaller diameter, so that the high-temperature mechanical properties can be tested more accurately.

[0075] The present invention uses an in-situ steel melting method. During the solidification process of the test bar after melting, the tension device is started to stretch the test bar at a suitable rate. The following three methods can be adopted to comprehensively test the high-temperature mechanical properties of the metal in the mushy zone under different conditions:

[0076] Adjust the water flow of the water cooling chuck to control the cooling rate of the test bar, so as to measure the high-temperature mechanical properties of the metal mushy zone at different cooling rates;

[0077] Adjust the stretching device to control the stretching rate during the cooling and heat preservation process of the sample, so as to measure the high-temperature mechanical properties of the metal mushy zone at different stretching rates;

[0078] The induction coil is adjusted to control the insulation temperature of the test rod, so as to measure the high-temperature mechanical properties of metals at different temperatures; the device uses stress sensors and thermocouples to simultaneously measure the loaded stress, heating and cooling curves, and temperature, and uses a stretching device to measure the stretching rate, which corresponds to the actual metal solidification process.

[0079] The working process of the in-situ heated mushy zone high temperature mechanical properties testing device of the present invention is as follows: (taking the measurement of the mushy zone high temperature mechanical properties of 24Mn steel, T10 steel and 6061 aluminum alloy at different cooling rates, different temperatures and different stretching rates as examples)

[0080] 1. Measure the high temperature mechanical properties of 24Mn steel in the mushy zone at different cooling rates:

[0081] Process Fe-24Mn high manganese steel into a dog-bone test rod with a length of 200 mm, a diameter of 10 mm, and a middle diameter of 5 mm. The outer layer of the test rod is covered with a ceramic crucible, and the outer layer of the ceramic crucible is covered with an insulation layer. The thermocouple is pre-buried outside the ceramic crucible, placed inside the induction coil, and placed in the furnace body. The two ends of the test rod are clamped with water-cooled chucks, and the furnace door is closed;

[0082] Turn on the power and the vacuum system starts;

[0083] Pump to high vacuum up to 1.5×10 -3 Pa later, the test bar was heated at a heating rate of 10°C / s;

[0084] When the test bar temperature reaches 1419°C (liquidus is 1389°C), it is superheated by 30°C and kept warm for 5 minutes;

[0085] After the holding time is over, set the water flow rate of the water cooling chucks at both ends of the test rod, control the cooling rate to 0.9℃ / s and 1.5℃ / s respectively, and start cooling;

[0086] During the cooling process, when the test bar temperature reaches 1313°C (solid phase ratio 0.85, i.e., mushy zone), the stretching device is started to stretch the test bar at a stretching rate of 5 mm / min. The data acquisition system records all data throughout the process. The test bar is stretched until it yields and then the test is stopped.

[0087] After the test, the test data obtained were analyzed, including stress, temperature, time and other data. The data were processed to obtain the high-temperature mechanical properties of 24Mn steel in the mushy zone under different cooling rates. The tensile curves and fracture morphologies under different cooling rates are shown in Figure 2. Figure 4 shown.

[0088] 2. Measure the high temperature mechanical properties of T10 steel in the mushy zone at different tensile rates:

[0089] T10 steel is processed into a test rod with a length of 200 mm at both ends and a diameter of 10 mm. The outer layer of the test rod is covered with a ceramic crucible, and the outer layer of the ceramic crucible is covered with a thermal insulation layer with thick ends and a thin middle. The thermocouple is pre-buried outside the ceramic crucible, placed inside the induction coil, and placed in the furnace body. The water cooling heads at both ends of the test rod are clamped, and the furnace door is closed;

[0090] Turn on the power and the vacuum system starts;

[0091] Pump to high vacuum up to 1.5×10 -3 Pa later, the test bar was heated at a heating rate of 10°C / s;

[0092] When the test bar temperature reaches 1451°C (liquidus is 1421°C), overheat by 30°C and keep warm for 5 minutes;

[0093] After the holding time is over, set the water flow rate of the water cooling chucks at both ends of the test rod, control the cooling rate to 1℃ / s, and start cooling;

[0094] During the cooling process, when the temperature of the test bar reaches 1355°C (solid phase ratio is 0.85, i.e., the mushy zone), the stretching device is started, and the test bar is stretched at a stretching rate of 0.25 mm / min and 0.5 mm / min respectively. The data acquisition system records all data throughout the process, and the test bar is stretched until it yields and then the test is stopped;

[0095] After the test, the test data obtained were analyzed, including stress, temperature, time and other data. The data were processed to obtain the high-temperature mechanical properties of T10 steel in the mushy zone at different tensile rates. The tensile curves and fracture morphologies at different tensile rates are shown in Figure 2. Figure 5 shown.

[0096] 3. Measure the high temperature mechanical properties of Fe-24Mn high manganese steel at different temperatures ( Figure 2 structure):

[0097] Process Fe-24Mn high manganese steel into a dog-bone test rod with a length of 200 mm, a diameter of 10 mm at both ends and a middle diameter of 5 mm. The outer layer of the test rod is covered with a ceramic crucible, and the outer layer of the ceramic crucible is covered with an insulation layer. The thermocouple is pre-buried outside the ceramic crucible, placed inside the induction coil, and placed in the furnace body. The water-cooled chucks at both ends of the test rod are clamped, and the furnace door is closed;

[0098] Turn on the power and the vacuum system starts;

[0099] Pump to high vacuum up to 1.5×10 -3 Pa later, the test bar was heated at a heating rate of 10°C / s;

[0100] When the test bar temperature reaches 1000℃ and 1100℃ (solidus is 1225℃), the test is carried out in the temperature range from solidus to 200℃ below the solidus, and the temperature is kept for 5 minutes;

[0101] After the holding time is over, the stretching device is started to stretch the test bar at a stretching rate of 1mm / min. The data acquisition system records all data during the whole process. The test bar is stretched until it yields and then the test is stopped.

[0102] At the end of the test, the test data obtained were analyzed, including stress, temperature, time and other data, and the data were processed to obtain the high-temperature mechanical properties of Fe-24Mn high manganese steel at temperature.

[0103] 4. Measure the high temperature mechanical properties of 6061 aluminum alloy at different temperatures ( Figure 3 structure):

[0104] 6061 aluminum alloy is processed into a test rod with a length of 200 mm at both ends and a diameter of 10 mm. The outer layer of the test rod is covered with a ceramic crucible. The outer layer of the ceramic crucible is covered with a thick insulation layer at both ends and a thin insulation layer in the middle. The thermocouple is embedded in the outside of the ceramic crucible, placed inside the induction coil, and placed in the furnace body. The water cooling heads at both ends of the test rod are clamped, and the furnace door is closed.

[0105] Turn on the power and the vacuum system starts;

[0106] Pump to high vacuum up to 1.5×10 -3 Pa later, the test bar was heated at a heating rate of 10°C / s;

[0107] When the test bar temperature reaches 300°C and 400°C (solidus is 582°C), the test is carried out in the temperature range from the solidus to 200°C below the solidus, and the temperature is kept for 5 minutes;

[0108] After the holding time is over, the stretching device is started to stretch the test bar at a stretching rate of 1mm / min. The data acquisition system records all data during the whole process. The test bar is stretched until it yields and then the test is stopped.

[0109] At the end of the test, the test data obtained were analyzed, including stress, temperature, time and other data, and the data were processed to obtain the high-temperature mechanical properties of 6061 aluminum alloy at different temperatures.

[0110] The present invention avoids the inconvenience caused by the molten casting method by using an in-situ heating system. The sample is heated by an induction heating radiation tube, and the heating and cooling rates of the sample can be controlled. The experiment is in a high vacuum environment, and a force frame is formed outside the furnace body, so that the stretching mechanism and the sample inside the furnace body are not subjected to external forces, reducing the influence of vacuum changes on the measurement; the influence of electric current heating samples on the plasticity and strength of the metal is avoided, and the stretching rate and temperature of the sample can be controlled, so that the high-temperature mechanical properties of the metal under the same conditions can be accurately measured; the active stretching device is equipped, which gets rid of the limitation of the sand mold and can produce different stress conditions, so as to meet different The stress conditions for measuring high-temperature mechanical properties of metals; the stretching device can accurately record the stretching rate, and the high-temperature mechanical properties can be accurately measured through the data acquisition system; equipped with a micro-displacement sensor, it can synchronously measure the displacement caused by thermal expansion when different metals are heated or cooled to a semi-solid state, and control the displacement to offset the error in the mechanical properties of the mushy zone caused by thermal expansion; it has gotten rid of the inability of traditional mechanical properties testing devices to test the mechanical properties of metals when heated or cooled to a semi-solid state, and filled in the mechanical properties data of the mushy zone of different metals; two sample preparation schemes that can form a high temperature gradient area are designed, and a higher temperature gradient can more accurately test high-temperature mechanical properties.

[0111] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. An in-situ heated pasty zone high temperature mechanical properties testing device, characterized in that: include: Stretching device, left furnace door, furnace body, connecting rod, left water-cooling chuck, micro-displacement sensor, test rod, thermocouple, induction coil, insulation layer, ceramic crucible, right water-cooling chuck, rigid beam, load-bearing beam, right furnace door, stress sensor, vacuum device, guide rail bracket of stretching device; The stretching device is arranged on the outer left side of the furnace body for stretching the test rod; the left furnace door and the right furnace door are arranged on both sides of the furnace body for closing the furnace body; the left water-cooling chuck, the right water-cooling chuck, the test rod, the ceramic crucible, the thermocouple, the induction coil, the insulation layer, the micro-displacement sensor, and the stress sensor are arranged in the furnace cavity of the furnace body; the vacuum device is arranged at the bottom of the furnace body and communicates with the inside of the furnace body; the lower end of the stretching device is equipped with the stretching device guide rail bracket, which can move left and right on the stretching device guide rail bracket and lock at any position of the sliding range; the micro-displacement sensor is arranged inside the left water-cooling chuck, and the other end is connected to the test rod. The micro-displacement sensor is used to synchronously measure the test rod in the high temperature range due to The displacement caused by thermal expansion; the stress sensor is arranged beside the right furnace door in the furnace body and fixed on the right furnace door, the stress sensor is threadedly connected to one end of the right water-cooling chuck, and the other end of the right water-cooling chuck is threadedly connected to the test rod, and the stress sensor is used to synchronously measure the external force applied by the stretching device; the stretching device, the micro-displacement sensor, the stress sensor and the coaxiality of the test rod; the left water-cooling chuck and the right water-cooling chuck are fixed to the left and right ends of the test rod by threaded connection, which are used to accurately control the size of the water flow and control the speed of axial heat dissipation of the test rod during the cooling process; the load-bearing beam is arranged on the outside of the furnace body, connected to the left furnace door and the right furnace door, and is used to apply the force applied to the stress sensor to the load-bearing beam; The ceramic crucible is a hollow cylinder, whose inner diameter is equal to the diameter of the test rod. The test rod is arranged in the ceramic crucible and is coaxial with the ceramic crucible. The outer side of the ceramic crucible is covered with the insulation layer, and the outer side of the insulation layer is the induction coil. The induction coil is used for induction heating to heat or melt the part of the test rod wrapped by the induction coil. The thermocouple is pre-buried on the outer wall of the ceramic crucible and is used for synchronously measuring the temperature of the test rod. The vacuum device is started, and after being drawn to a high vacuum state, the heating power is adjusted to heat the test rod to above the liquidus line, and the test rod is cooled to the target temperature of the mushy zone at a certain cooling rate, and the water flow of the left water-cooling chuck and the right water-cooling chuck is controlled to control the stretching rate of the stretching device. After the stretching device is started, the test rod is stretched at a certain cooling rate and stretching rate during the cooling process of the test rod, and the high-temperature mechanical properties of the mushy zone of the metal test rod can be measured in a relatively short time, avoiding the influence of dendrite coarsening on the mechanical property test of the mushy zone; in addition, different temperatures, cooling rates, and stretching rates are selected to stretch the test rod, and the high-temperature mechanical properties of the metal test rod under different conditions can also be measured; the invention can quantitatively and accurately test the high-temperature mechanical properties of the metal in the mushy zone.

2. The in-situ heated pasty zone high temperature mechanical properties testing device according to claim 1, characterized in that: The stretching device is fixed to one end of the connecting rod, and the other end of the connecting rod is connected to the left water-cooling chuck; the stretching device is used to actively load external force, apply external force during the heating, cooling and insulation process of the test rod, control the stretching rate of the test rod during the loading process, and measure the high-temperature mechanical properties of the mushy zone of the test rod.

3. The in-situ heated pasty zone high temperature mechanical properties testing device according to claim 1, characterized in that: The left water-cooling chuck and the right water-cooling chuck are both composed of a fixture and a cooling water channel, and the cooling water channel is installed on the fixture; the left water-cooling chuck and the right water-cooling chuck are connected to a circulating water cooler, which is used to control the speed of heat dissipation of the test rod during the cooling process, control the cooling rate of the test rod, and measure the high-temperature mechanical properties of the metal test rod at different cooling rates.

4. The in-situ heated pasty zone high temperature mechanical properties testing device according to claim 1, characterized in that: The in-situ heated pasty zone high temperature mechanical properties testing device also includes a rigid beam, which is horizontally welded to the right furnace door and threadedly connected to the right water-cooled chuck for fixing the chuck; the rigid beam also includes a spirit level and an adjustment mechanism to ensure the level of the rigid beam and the test rod.

5. The in-situ heated pasty zone high temperature mechanical properties testing device according to claim 1, characterized in that: The load-bearing beam is a rigid connecting rod, which is arranged on the outside of the furnace body and connects the left furnace door and the right furnace door. It is used to apply the force applied to the stress sensor to the load-bearing beam, and form a force frame with the furnace body base, so that the inside of the furnace body is no longer subjected to force, so that the vacuum chamber formed inside the furnace body is not affected by the external force applied by the stretching device, which is used to avoid errors caused by the deformation of the vacuum shell and the sealing rubber ring under force and eliminate the influence of the vacuum degree on the measurement.

6. The in-situ heated pasty zone high temperature mechanical properties testing device according to claim 1, characterized in that: The micro-displacement sensor is arranged inside the left water-cooling chuck, and the other end is connected to the test rod. The micro-displacement sensor is used to synchronously measure the displacement caused by thermal expansion when the test rod is heated or cooled to the mushy zone. The error of the mechanical properties of the mushy zone caused by thermal expansion is offset by controlling the displacement of the test rod, thereby improving the accuracy of the high-temperature mechanical properties test of the mushy zone.

7. The in-situ heated pasty zone high temperature mechanical properties testing device according to claim 1, characterized in that: The ceramic crucible is a hollow cylinder, the inner diameter of which is equal to the diameter of the test rod, and the test rod is arranged in the hollow cylinder and is coaxial with the ceramic crucible; when the test rod is heated or cooled to a pasty zone, the ceramic crucible has excellent high temperature resistance, chemical stability and low thermal expansion, so it can play a protective role for the test rod in a semi-solid state and ensure that there will be no leakage, so that the in-situ heating high-temperature mechanical properties testing device can measure the mechanical properties of the test rod in the high-temperature pasty zone.

8. The in-situ heated pasty zone high temperature mechanical property testing device according to claim 1, characterized in that: The ceramic crucible is sheathed with the insulation layer on the outside, and the insulation layer is provided with the induction coil on the outside. The induction coil is used for induction heating, so that the temperature of the test rod wrapped by the induction coil rises, and a uniform high-temperature zone is formed in this part of the test rod; the left water-cooling chuck and the right water-cooling chuck are fixed at the left and right ends of the test rod, so that a low-temperature zone is formed except for the part wrapped by the induction coil, thereby generating a high temperature gradient zone between the uniform temperature zone and the low temperature zone; the in-situ heated mushy zone high-temperature mechanical properties testing device is designed with two sample preparation schemes that can form a high temperature gradient zone, one of which is to reduce the diameter of the sample of the tested section, and the other is to adjust the thickness distribution of the insulation layer; the tested section is at a uniform temperature and the high temperature gradient on both sides can more accurately test the high-temperature mechanical properties.

9. The in-situ heated pasty zone high temperature mechanical property testing device according to claim 1, characterized in that: The in-situ heated pasty zone high temperature mechanical properties testing device also includes a data signal acquisition control system, which is used to convert the temperature, stress, stretching rate and cooling rate obtained by the thermocouple, the stress sensor, the stretching device, the left water-cooling chuck and the right water-cooling chuck into data signals and collect and store them throughout the process; the acquisition frequency of the data signal control acquisition system is 1Hz-100Hz.

10. The in-situ heated pasty zone high temperature mechanical property testing device according to claim 1, characterized in that: The maximum heating temperature of the in-situ heated pasty zone high temperature mechanical properties testing device is 2000°C; the heating and cooling rate range is 0.01-100K / s; The temperature control error of the temperature rise and fall is less than ±1k; the cold limit vacuum degree of the in-situ heated paste zone high temperature mechanical properties test device is 1.5×10 -3 Pa; the maximum test force of the stretching device is 20kN; the stretching rate range is 0.001-3mm / s; the effective stretching range is 50mm; the range of the stress sensor is 2KN, 5kN, 10kN and 20kN, which is replaceable, and the error is ≤0.5%; the cooling water flow rate of the water-cooled chuck is 0.5L / min-10L / min; the current frequency passed through the induction coil is 10kHz-30kHz, which is set according to the test requirements.

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