Titanium alloy differential temperature deformation capacity evaluation method based on asymmetric temperature

Abstract

This invention provides a method for evaluating the differential temperature deformation capability of titanium alloys based on asymmetric temperatures. The method includes the following steps: Step 1, preparing a first-temperature mold, a second-temperature mold, and a titanium alloy sample; Step 2, setting simulated test conditions, including the target temperature T of the first-temperature mold. H The target temperature T of the second temperature mold C and the target temperature T of the sample S Step 3: Establish a stable temperature field; Step 4: Perform differential temperature compression: Start the thermal simulation testing machine and perform axial compression deformation on the sample according to the preset deformation rate until the sample reaches the preset conditions; Step 5: Data acquisition and processing; Step 6: Performance evaluation. Small-scale tests were conducted using the samples. By setting up a first temperature mold and a second temperature mold, the asymmetric temperature field during the actual differential temperature forming process was reproduced, ensuring that the test conditions closely matched the actual field conditions. This provides a scientific basis for the precise formulation of differential temperature forming process parameters and avoids the blind selection of parameters.

Description

Technical Field

[0001] This invention relates to the field of metallic material evaluation technology, and more specifically, to a method for evaluating the differential temperature deformation capacity of titanium alloys based on asymmetric temperature. Background Technology

[0002] Titanium alloys are widely used in the aerospace field due to their high specific strength and good corrosion resistance. However, titanium alloys have high deformation resistance and poor plasticity at room temperature, and usually require hot forming. In actual differential forming processes (such as differential rolling and gradient temperature forging), different parts of the workpiece are at different temperatures. This asymmetrical temperature field significantly affects the material's flow stress, plastic deformation capacity, and microstructure evolution.

[0003] Currently, the evaluation of the high-temperature mechanical properties of titanium alloys mainly relies on conventional isothermal hot compression tests, in which the titanium alloy sample and the upper and lower molds are heated to the same temperature. This traditional method has significant limitations:

[0004] (1) Cannot simulate differential temperature process conditions: Isothermal tests cannot reproduce the asymmetric temperature field of the material during the actual differential temperature forming process. Therefore, the obtained rheological stress data and constitutive model are different from the actual process conditions.

[0005] (2) Inaccurate evaluation of deformation capacity: The plasticity of the material (such as the maximum deformation) measured under a uniform temperature field cannot truly reflect its deformation behavior under temperature difference conditions, which may lead to defects such as cracking due to improper parameter selection in actual production.

[0006] (3) Long process development cycle and high cost: Due to the lack of effective laboratory evaluation methods, the development of new processes relies heavily on trial and error in field tests, which consumes a lot of time and economic costs. Summary of the Invention

[0007] In view of this, the present invention aims to propose a method for evaluating the differential temperature deformation capacity of titanium alloys based on asymmetric temperature, so as to solve the shortcomings of the existing isothermal hot compression test technology and the lack of effective laboratory evaluation means for titanium alloys in actual differential temperature forming processes.

[0008] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0009] A method for evaluating the differential temperature deformation capability of titanium alloys based on asymmetric temperature includes the following steps:

[0010] Step 1: Prepare the first temperature mold, the second temperature mold, and the titanium alloy sample;

[0011] Step 2: Set up simulation test conditions based on the temperature at which the titanium alloy will be processed into a workpiece. The simulation test conditions include the target temperature T of the first temperature mold. H The target temperature T of the second temperature mold C and the target temperature T of the sample S ;

[0012] Step 3: Establish a stable temperature field:

[0013] Start the temperature control systems corresponding to the first temperature mold, the second temperature mold, and the sample. After the temperatures of both molds and the sample reach the set target temperatures and stabilize, maintain the temperature for a period of time. 保温 This allows a space from T to be established inside the sample. H End to T C Stable axial temperature gradient at the end;

[0014] Step 4: Perform differential temperature compression.

[0015] Start the thermal simulation testing machine and subject the specimen to axial compression deformation at a preset deformation rate until the specimen reaches the preset conditions.

[0016] Step 5: Data Acquisition and Processing;

[0017] Step 6: Performance Evaluation.

[0018] Furthermore, in step three, the sample is placed between the first temperature mold and the second temperature mold, with one end of the sample in contact with the first temperature mold and the other end at a distance of 20-30 cm from the second temperature mold.

[0019] Furthermore, in step two, based on the actual production process, the highest temperature required to process the titanium alloy into the workpiece is taken as the target temperature T. H The minimum required temperature is T C And the target temperature T of the sample S The target temperature T of the first temperature mold H Maintain consistency.

[0020] Furthermore, the first temperature mold is provided with a first resistance heater and a first thermocouple, the second temperature mold is provided with a forced cooling channel and a second thermocouple, and the outer periphery of the sample is provided with a third electric heater and a third thermocouple.

[0021] Furthermore, the first temperature mold can be heated and stabilized to 300~1000℃, and the second temperature mold can be cooled and maintained at 25~1000℃.

[0022] Furthermore, a heat insulation element is provided between the first temperature mold and the second temperature mold.

[0023] Furthermore, in step four, the preset condition is to reach a preset total strain or for visible cracks to appear on the sample surface.

[0024] Furthermore, water or argon gas is introduced into the forced cooling channel as a cooling medium. The second thermocouple can sense and measure the actual temperature of the second temperature mold in real time and feed the temperature signal back to the temperature control system corresponding to the second temperature mold.

[0025] Furthermore, throughout the entire deformation process, the temperature control systems corresponding to the first and second temperature molds operate independently to maintain the set temperature difference environment.

[0026] Compared with existing technologies, the method for evaluating the differential temperature deformation capability of titanium alloys based on asymmetric temperature described in this invention has the following advantages:

[0027] (1) In a laboratory environment, a small-scale test was conducted using the sample. By setting up a first temperature mold and a second temperature mold, the asymmetric temperature field in the actual temperature difference forming process was reproduced, so that the test conditions were highly consistent with the actual industrial site.

[0028] (2) It can directly obtain the real rheological behavior and plastic limit of titanium alloy materials under temperature difference conditions, providing a scientific basis for the accurate formulation of differential temperature forming process parameters, which is conducive to evaluating the cost of processing titanium alloys into workpieces and avoiding the blindness of parameter selection.

[0029] (3) It is low in cost, easy to operate, and has low implementation cost and clear methods and procedures.

[0030] (4) This invention is not only applicable to titanium alloys, but can also be extended to the study of differential temperature forming performance of other difficult-to-deform metal materials (such as high-strength steel and nickel-based high-temperature alloys). Attached Figure Description

[0031] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0032] Figure 1 This is a schematic diagram showing the placement of the first temperature mold, the second temperature mold, and the sample according to the present invention.

[0033] Figure 2 This is a schematic diagram illustrating the state of differential temperature compression performed according to the present invention;

[0034] Figure 3 This is the true stress-true strain curve of Embodiment 1 of the present invention.

[0035] Explanation of reference numerals in the attached figures:

[0036] 1. First temperature mold; 2. Second temperature mold; 3. Sample. Detailed Implementation

[0037] The present invention will be further described below with reference to specific embodiments. First, it should be noted that the data in the following experimental examples were obtained by the inventors through numerous experiments. Due to space limitations, only a portion of these data is shown in the specification, and those skilled in the art can understand and implement the present invention based on this data. These embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the contents of this invention, those skilled in the art can make various modifications or alterations to the invention, and these modifications or alterations also fall within the scope of protection of this application.

[0038] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0039] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0040] This invention proposes a method for evaluating the differential temperature deformation capability of titanium alloys based on asymmetric temperatures, specifically including the following steps:

[0041] Step 1: Prepare the first temperature mold 1, the second temperature mold 2, and the titanium alloy sample 3;

[0042] Step 2: Set up simulation test conditions based on the temperature at which the titanium alloy will be processed into a workpiece. The simulation test conditions include the target temperature T of the first temperature mold 1. H The target temperature T of the second temperature mold 2 C and the target temperature T of sample 3 S ;

[0043] Step 3: Establish a stable temperature field:

[0044] The temperature control systems corresponding to the first temperature mold 1, the second temperature mold 2, and the sample 3 are activated. After the temperatures of both molds and the sample 3 reach the set target temperatures and stabilize, they are kept at these temperatures for a period of time. 保温 This allows a space from T to be established inside sample 3. H End to T C Stable axial temperature gradient at the end;

[0045] Step 4: Perform differential temperature compression.

[0046] Start the thermal simulation testing machine and perform axial compression deformation on the sample 3 according to the preset deformation rate until the sample 3 reaches the preset conditions.

[0047] Step 5: Data Acquisition and Processing;

[0048] Step 6: Performance Evaluation.

[0049] Specifically, in step three, the sample 3 is placed between the first temperature mold 1 and the second temperature mold 2, with one end of the sample 3 in contact with the first temperature mold 1 and the other end 20-30 cm away from the second temperature mold 2. The first temperature mold 1 is set as a high-temperature mold, and the second temperature mold 2 as a low-temperature mold. By ensuring direct contact between one end of the sample 3 and the first temperature mold 1, heat transfer from the first temperature mold 1 to the sample 3 is facilitated. Maintaining a certain distance between the other end of the sample 3 and the second temperature mold 2 prevents the high temperature of the sample 3 from causing a rapid temperature rise in the second temperature mold 2. In a laboratory environment, by setting up the first temperature mold 1 and the second temperature mold 2, the asymmetric temperature field during the actual temperature difference forming process is reproduced, making the test conditions highly consistent with the actual industrial environment.

[0050] The sample 3 can be placed at one end in contact with the first temperature mold 1 using a support fixture.

[0051] In step two, based on the actual production process, the highest temperature required to process the titanium alloy into the workpiece is taken as the target temperature T. H The minimum required temperature is T C And the target temperature T of sample 3 S The target temperature T of the first temperature mold 1 H Maintain consistency.

[0052] As a specific example of the present invention, the first temperature mold 1 is made of a high-temperature resistant alloy, such as a molybdenum alloy, and has a first resistance heater and a first thermocouple disposed inside. The first resistance heater serves as a heat source, converting electrical energy into heat energy when energized, for heating the first temperature mold 1. The first thermocouple can sense and measure the actual temperature of the first temperature mold 1 in real time and feed the temperature signal back to the temperature control system corresponding to the first temperature mold 1. The temperature control system corresponding to the first temperature mold 1 is electrically connected to the first resistance heater and is used to adjust the power of the first resistance heater according to the received temperature signal, thereby controlling the heating state of the first resistance heater.

[0053] More specifically, the first temperature mold 1 can be heated and stabilized to 300~1000℃, which is the conventional hot forming temperature of titanium alloy.

[0054] The second temperature mold 2 is equipped with a forced cooling channel and a second thermocouple inside. Water or argon gas is introduced into the forced cooling channel as a cooling medium. The second thermocouple can sense and measure the actual temperature of the second temperature mold 2 in real time and feed the temperature signal back to the temperature control system corresponding to the second temperature mold 2. The temperature control system corresponding to the second temperature mold 2 is electrically connected to the forced cooling channel and is used to adjust the flow rate of the cooling medium according to the received temperature signal, thereby controlling the temperature of the second temperature mold 2.

[0055] More specifically, the second temperature mold 2 can cool and maintain the temperature at 25~1000°C, which is the low temperature condition for titanium alloy forming.

[0056] A third electric heater and a third thermocouple are disposed on the outer periphery of the sample 3. The third electric heater serves as a heat source to heat the sample 3 to the target temperature T. S And the target temperature T of the first temperature mold 1 H The same applies. The third thermocouple can sense and measure the actual temperature of sample 3 in real time and feed the temperature signal back to the temperature control system corresponding to sample 3. The temperature control system corresponding to sample 3 is electrically connected to the third resistance heater and is used to adjust the power of the third resistance heater according to the received temperature signal, thereby controlling the heating status of the third resistance heater.

[0057] Throughout the deformation process, the temperature control systems corresponding to the first temperature mold 1 and the second temperature mold 2 operate independently to maintain the set temperature difference environment.

[0058] As a preferred example of the present invention, heat-insulating elements are provided on the surfaces of the first temperature mold 1 and the second temperature mold 2 to minimize radial heat conduction between them and reduce mutual interference between the two temperature molds, thereby helping to maintain a stable axial temperature gradient. Specifically, the heat-insulating elements are made of ceramic materials with low thermal conductivity or other heat-insulating materials, such as zirconium oxide or alumina.

[0059] In step four, the preset condition is to reach a preset total strain or for visible cracks to appear on the surface of sample 3.

[0060] In step five, parameters such as the compressive force, piston displacement, and time of the thermal simulation testing machine can be collected and recorded in real time. Based on these parameters, the true stress and true strain curves under the corresponding temperature difference and deformation rate conditions can be calculated and plotted.

[0061] The present invention enables the acquisition of the following test parameters to evaluate the cost of machining the titanium alloy material corresponding to sample 3 into a workpiece.

[0062] (1) Deformation resistance analysis: Analyze the peak stress and steady-state rheological stress under different temperature difference conditions from the rheological stress curve.

[0063] (2) Plasticity assessment: The maximum true strain or engineering strain that does not show cracks on the surface of sample 3 after compression is used as the index of the differential temperature deformation capacity of titanium alloy material under the corresponding temperature difference. The larger the maximum true strain, the better the forming performance of the material under the temperature difference. Therefore, it is not necessary to remove too much of the surface part of the finished workpiece, thus reducing the cost.

[0064] (3) Observation of structure: Metallographic dissection of the deformed sample 3 was performed to observe the microstructure gradient from the high temperature end to the low temperature end (e.g., grain size, phase structure evolution) and establish the relationship between process structure and performance.

[0065] The present invention provides a method for evaluating the cost of machining titanium alloys into workpieces, which can be achieved by changing T H T C A series of tests were conducted on ΔT (i.e., deformation rate) and deformation rate (controlled by the hydraulic device of the thermal simulation testing machine) to systematically evaluate the deformation capacity of titanium alloys under different temperature difference conditions. This invention can effectively simulate differential temperature processes, improving the accuracy of deformation capacity evaluation. Better deformation capacity indicates that the overall quality of the workpiece is acceptable under the corresponding temperature difference conditions, allowing for precise selection of appropriate forming temperatures to reduce costs. Based on the small-scale testing of this invention, favorable temperature difference conditions for titanium alloy processing can be identified, providing a reasonable selection for actual processing and reducing costs.

[0066] Furthermore, current processing techniques for titanium alloys typically involve multiple trials to continuously adjust the temperature field and explore optimal processing conditions. If the selected temperature parameters are inappropriate during the machining process, the resulting workpiece will not meet quality requirements, often necessitating cutting to the workpiece surface. This not only hinders near-net-shape forming but also increases processing costs. This invention allows for the determination of appropriate temperature parameters through small-scale trials, saving both cost and time.

[0067] The present invention has the following beneficial effects:

[0068] (1) In a laboratory environment, a small-scale test was conducted using sample 3. By setting up the first temperature mold 1 and the second temperature mold 2, the asymmetric temperature field in the actual temperature difference forming process was reproduced, so that the test conditions were highly consistent with the actual industrial site.

[0069] (2) It can directly obtain the real rheological behavior and plastic limit of titanium alloy materials under temperature difference conditions, providing a scientific basis for the accurate formulation of differential temperature forming process parameters, which is conducive to evaluating the cost of processing titanium alloys into workpieces and avoiding the blindness of parameter selection.

[0070] (3) It is low in cost, easy to operate, and has low implementation cost and clear methods and procedures.

[0071] (4) This invention is not only applicable to titanium alloys, but can also be extended to the study of differential temperature forming performance of other difficult-to-deform metal materials (such as high-strength steel and nickel-based high-temperature alloys).

[0072] Example 1

[0073] The cost of machining TC11 titanium alloy into workpieces is evaluated by assessing its differential temperature deformation capacity and deformation resistance.

[0074] Step 1: Place the 8mm×12mm TC11 titanium alloy cylindrical sample 3 between the first temperature mold 1 and the second temperature mold 2, with one end of the TC11 titanium alloy cylindrical sample 3 in contact with the first temperature mold 1 and the other end 25cm away from the second temperature mold 2.

[0075] Step 2: Set up simulation test conditions based on the temperature required to process the TC11 titanium alloy into the desired workpiece. The simulation test conditions include the target temperature T of the first temperature mold 1. H =950℃, the target temperature T of the second temperature mold 2 C =400℃ and the target temperature T of sample 3 S =950℃, then ΔT=550℃.

[0076] Step 3: Activate the temperature control systems corresponding to the first temperature mold 1, the second temperature mold 2, and the sample 3. After the temperature of the first temperature mold 1 stabilizes at 950℃, the temperature of the second temperature mold 2 stabilizes at 400℃, and the temperature of the sample 3 stabilizes at 400℃, maintain the temperature for 3 minutes (t). 保温 =3min), to ensure that a uniform temperature field is formed inside sample 3.

[0077] Step 4: Start the thermal simulation testing machine, clamp it at both ends of sample 3, and test at 0.1s intervals. -1 The specimen 3 was subjected to axial compression deformation at a certain deformation rate until the true strain of the specimen 3 reached 0.9.

[0078] Step 5: Collect data in real time and plot the true stress-true strain curve as shown below. Figure 3 As shown.

[0079] The true stress-true strain curves obtained in Example 1 can be used to evaluate deformation resistance and plasticity.

[0080] Deformation resistance analysis: Under a temperature difference of ΔT = 550℃, the peak stress of TC11 specimen 3 is 120MPa.

[0081] Plasticity assessment: After compression, TC11 specimen 3 developed cracks at a true strain of 0.7.

[0082] In Example 1, a small-sized TC11 sample 3 was used as a small-scale test sample. An axial compression deformation test under a temperature difference of ΔT=550℃ was conducted to simulate the processing of large-sized TC11 titanium alloy into the required workpiece under the same temperature difference. This also allowed for the assessment of the cost of processing TC11 titanium alloy into workpieces. The experimental results showed that the small-sized TC11 sample 3 cracked under the ΔT=550℃ temperature difference condition. This indicates that in actual industrial production, workpieces obtained after subjecting TC11 titanium alloy to high and low temperature processing conditions (with a temperature difference of 550℃) need to be cut to remove the parts whose surface was exposed to the low-temperature conditions and whose performance was affected, leading to increased costs.

[0083] Example 2

[0084] The cost of machining TA1 titanium alloy into workpieces is evaluated by assessing its differential temperature deformation capacity and deformation resistance.

[0085] Step 1: Place the 10mm×15mm TA15 titanium alloy cylindrical sample 3 between the first temperature mold 1 and the second temperature mold 2, with one end of the TA15 titanium alloy cylindrical sample 3 in contact with the first temperature mold 1 and the other end 30cm away from the second temperature mold 2.

[0086] Step 2: Set up simulation test conditions based on the temperature required to process the TA15 titanium alloy into the desired workpiece. The simulation test conditions include the target temperature T of the first temperature mold 1. H =320℃, the target temperature T of the second temperature mold 2 C =25℃ and the target temperature T of sample 3 S =320℃, then ΔT=295℃.

[0087] Step 3: Start the temperature control system corresponding to the first temperature mold 1, the temperature control system corresponding to the second temperature mold 2, and the temperature control system corresponding to the sample 3. After the temperature of the first temperature mold 1 stabilizes at 320℃, the temperature of the second temperature mold 2 stabilizes at 25℃, and the temperature of the sample 3 stabilizes at 320℃, keep it at that temperature for 10 minutes (t_keeping = 10 minutes) to ensure that a uniform temperature field is formed inside the sample 3.

[0088] Step 4: Start the thermal simulation testing machine, clamp it at both ends of sample 3, and test at 0.01s intervals. -1 and 1.0s -1 Two sets of tests were conducted to measure the deformation rate of specimen 3, and axial compression deformation was performed on specimen 3 until the true strain of specimen 3 reached 0.8.

[0089] The true stress-true strain curves obtained in Example 2 can be used to evaluate deformation resistance and plasticity, thereby reflecting the cost of TA15 titanium alloy when the simulated test conditions are used as the actual processing conditions for the workpiece.

[0090] Deformation resistance analysis: Under a temperature difference of ΔT = 295℃, within 0.01s... -1 At 1.0 s⁻¹, the peak stress of TA15 sample 3 was 52 MPa; at 1.0 s⁻¹... -1 At that time, the peak stress of TA15 sample 3 was 78 MPa, indicating that TA15 titanium alloy still has obvious positive strain rate sensitivity under this temperature difference condition.

[0091] Plasticity assessment: at 0.1s -1 and 1.0s -1 At the deformation rate, neither of the two TA15 samples 3 cracked, indicating that TA15 titanium alloy has good differential temperature plasticity under a temperature difference of ΔT=295℃.

[0092] In Example 2, a small-sized TA15 sample 3 was used as a small-scale test sample. An axial compression deformation test under a temperature difference of ΔT=295℃ was conducted to simulate the processing of large-sized TA15 titanium alloy into the required workpiece under the same temperature difference. This also allowed for the assessment of the cost of processing TA15 into workpieces. The experimental results show that since the small-sized TA15 sample 3 maintained positive strain rate sensitivity and did not crack under a temperature difference of ΔT=295℃, it indicates that in actual industrial production, workpieces obtained by subjecting TA15 titanium alloy to high and low temperature processing conditions (with a temperature difference of 295℃) are qualified products. Cutting the final workpiece is unnecessary, which is beneficial for achieving near-net-shape finishes and does not increase processing costs.

[0093] Comparative Example 1

[0094] The selection of sample 3 is the same as in Example 1.

[0095] A cylindrical TC11 titanium alloy sample 3 with a diameter of ø8mm and a diameter of 12mm is placed between two first temperature molds 1, with each end of the sample 3 in contact with a first temperature mold 1.

[0096] Adjust the target temperature T of the two first temperature molds 1 H =950℃, target temperature T of sample 3 S =950℃. After the temperatures of the two first-temperature molds 1 and sample 3 reach the preset temperatures and are maintained for 3 minutes, the thermal simulation testing machine is started, clamped at both ends of sample 3, and the temperature is increased at 0.1s. -1 The specimen 3 was subjected to axial compression deformation at a certain deformation rate until the true strain of the specimen 3 reached 0.9.

[0097] Comparative Example 1 was tested under isothermal conditions. The peak stress of TC11 specimen 3 under isothermal conditions of 950℃ was 85MPa, and no microcracks appeared when the true strain was 0.9. Compared with Example 1, this shows that using differential temperature conditions can better simulate the processing of titanium alloys and reflect the differential temperature deformation capability of titanium alloys.

[0098] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various alterations and modifications without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A method for evaluating the differential temperature deformation capability of titanium alloys based on asymmetric temperature, characterized in that, The steps include the following: Step 1: Prepare the first temperature mold (1), the second temperature mold (2), and the titanium alloy sample (3); Step 2: Set up simulation test conditions based on the temperature at which the titanium alloy is processed into a workpiece. The simulation test conditions include the target temperature T of the first temperature mold (1). H The target temperature T of the second temperature mold (2) C and the target temperature T of sample (3) S ; Step 3: Establish a stable temperature field: Start the temperature control system corresponding to the first temperature mold (1), the temperature control system corresponding to the second temperature mold (2), and the temperature control system corresponding to the sample (3). After the temperatures of the two molds and the sample (3) reach the set target temperatures and stabilize, keep them at these temperatures for a period of time. 保温 This allows a space from T to be established inside the sample (3). H End to T C Stable axial temperature gradient at the end; Step 4: Perform differential temperature compression. Start the thermal simulation test machine and perform axial compression deformation on the sample (3) according to the preset deformation rate until the sample (3) reaches the preset conditions. Step 5: Data Acquisition and Processing; Step 6: Performance Evaluation.

2. The evaluation method according to claim 1, characterized in that, In step three, the sample (3) is placed between the first temperature mold (1) and the second temperature mold (2), with one end of the sample (3) in contact with the first temperature mold (1) and the other end at a distance of 20~30cm from the second temperature mold (2).

3. The evaluation method according to claim 1, characterized in that, In step two, based on the actual production process, the highest temperature required to process the titanium alloy into the workpiece is taken as the target temperature T. H The minimum required temperature is T C And the target temperature T of sample (3) S The target temperature T of the first temperature mold (1) H Maintain consistency.

4. The evaluation method according to claim 1, characterized in that, The first temperature mold (1) is provided with a first resistance heater and a first thermocouple inside, the second temperature mold (2) is provided with a forced cooling channel and a second thermocouple inside, and the outer periphery of the sample (3) is provided with a third electric heater and a third thermocouple.

5. The evaluation method according to claim 1, characterized in that, The first temperature mold (1) can heat and stabilize to 300~1000℃, and the second temperature mold (2) can cool and maintain the temperature to 25~1000℃.

6. The evaluation method according to claim 1, characterized in that, A heat insulation element is provided between the first temperature mold (1) and the second temperature mold (2).

7. The evaluation method according to claim 1, characterized in that, In step four, the preset condition is to reach the preset total strain or for visible cracks to appear on the surface of the sample (3).

8. The evaluation method according to claim 4, characterized in that, Water or argon gas is introduced into the forced cooling channel as a cooling medium. The second thermocouple can sense and measure the actual temperature of the second temperature mold (2) in real time and feed the temperature signal back to the temperature control system corresponding to the second temperature mold (2).

9. The evaluation method according to claim 1, characterized in that, Throughout the deformation process, the temperature control systems corresponding to the first temperature mold (1) and the second temperature mold (2) work independently to maintain the set temperature difference environment.

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