CN113846278B - Method for preparing oriented TiAl-based alloy by utilizing device for preparing oriented TiAl-based alloy through solid-state phase transition - Google Patents
Method for preparing oriented TiAl-based alloy by utilizing device for preparing oriented TiAl-based alloy through solid-state phase transition Download PDFInfo
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Abstract
A device for preparing oriented TiAl-based alloy by utilizing solid phase transition and a preparation method thereof relate to a device for preparing oriented TiAl-based alloy and a preparation method thereof. The invention aims to solve the problems that in the existing preparation process of the directional TiAl-based alloy, the surface layer of a sample is easy to generate lateral heat dissipation, and the process is complex. The liquid Ga-In alloy and the heat treatment test bar are positioned at the lower part In the vacuum chamber, the speed regulator is arranged at the bottom end of the heat treatment test bar, the lead end of the temperature measuring instrument extends into the vacuum chamber and is positioned In an effective heat treatment area, and the induction coil is sleeved at the outer side of the upper part of the heat treatment test bar. Placing a heat treatment sample in an induction coil in a vacuum chamber; adjusting the distance between the induction coil and the Ga-In alloy liquid level; heating the induction coil; vacuumizing and introducing argon; heating a measurement sample; when the temperature reaches the temperature range of the beta single-phase region of the TiAl-based alloy, stopping heating and preserving heat; carrying out directional heat treatment on the TiAl-based alloy test bar; and (5) after cooling, introducing air, and taking the workpiece. The method is used for preparing the oriented TiAl-based alloy.
Description
Technical Field
The invention relates to a device and a method for preparing an oriented TiAl-based alloy, in particular to a method for preparing an oriented TiAl-based alloy by utilizing a device for preparing an oriented TiAl-based alloy through solid-state phase transition, belonging to the technical field of material processing.
Background
TiAl-based alloy is known as the best material for replacing Ni-based high-temperature alloy at 600-900 ℃ due to the characteristics of small density, high specific strength, excellent high-temperature mechanical property and the like, and is expected to be applied to the preparation of aerospace turbine engine blades, so that the TiAl-based alloy is widely researched.
However, the alloy has the disadvantages of poor room temperature plasticity, easy oxidation of melt in the smelting process due to high chemical activity, coarse casting structure, serious component segregation and the like. The presence of these defects greatly limits the commercial production of this alloy. In order to optimize the microstructure of the TiAl-based alloy and improve the mechanical properties thereof, alloying methods and thermomechanical working methods are generally used. For TiAl-based alloy serving in a high-temperature environment, the directionally arranged columnar crystal or single crystal structure can greatly reduce the length of a transverse crystal boundary of the alloy, so that the high-temperature mechanical property of the alloy is obviously improved.
Generally, the method for preparing the directional TiAl-based alloy is mainly a directional solidification method. However, during directional solidification, the TiAl-based alloy melt inevitably comes into contact with the crucible or the coating material. For TiAl-based alloy melt with high chemical activity, the TiAl-based alloy melt is easy to chemically react with crucible materials or coating materials in the solidification process, so that the chemical components of the alloy and the directional growth of surface columnar crystals are influenced.
The invention discloses a directional annealing device and a method for preparing metal columnar crystals, which aim at preparing a TiAl-based alloy with a directionally arranged columnar crystal structure by using a heat treatment method, and particularly discloses a directional annealing device and a method for preparing metal columnar crystals, wherein the Ti-48Al-2Nb-2Cr alloy with 70% of rolling deformation is subjected to directional annealing, and the columnar crystal structure is finally obtained.
In summary, in the existing process of preparing the directional TiAl-based alloy, because the alloy melt is in contact with the crucible wall or the coating material, the composition of the directional TiAl-based alloy is affected, and the surface layer of the sample is prone to lateral heat dissipation in the traditional directional solidification process, so that the problem of large directional growth of the columnar crystal on the surface layer is affected, and meanwhile, the problem of complex process also exists.
Disclosure of Invention
The invention aims to solve the problems that in the existing preparation process of the directional TiAl-based alloy, because an alloy melt is contacted with a crucible wall or a coating material, the components of the directional TiAl-based alloy are influenced, and the surface layer of a sample is easy to generate lateral heat dissipation in the traditional directional solidification process, so that the directional growth of columnar crystals on the surface layer is influenced, and meanwhile, the process is complicated. Further provides a method for preparing the oriented TiAl-based alloy by utilizing a device for preparing the oriented TiAl-based alloy by solid-state phase transition.
The technical scheme of the invention is as follows: a temperature measuring device in the directional solidification process of a cold crucible comprises a vacuum chamber; the device also comprises a liquid Ga-In alloy, a speed regulator, an induction coil, a temperature measuring instrument, a heat treatment test rod and an Ar gas cylinder, wherein the liquid Ga-In alloy is positioned at the lower part In the vacuum chamber, the heat treatment test rod is vertically arranged In the vacuum chamber, the speed regulator is arranged at the bottom end of the heat treatment test rod In a dovetail groove connection mode and regulates and controls the pull-down speed of the heat treatment test rod In real time, the wire end of the temperature measuring instrument extends into the vacuum chamber and is positioned In an effective heat treatment area, the induction coil is sleeved on the outer side of the upper part of the heat treatment test rod and heats the effective heat treatment area on the heat treatment test rod, and the Ar gas cylinder is connected with the vacuum chamber.
The invention also provides a method for preparing the device of the oriented TiAl-based alloy by utilizing solid-state phase transition, which comprises the following steps:
placing a beta-solidified TiAl-based alloy heat treatment sample In a five-turn induction coil In a vacuum chamber, so that the axis of the heat treatment sample is completely overlapped with the central line of the induction coil, and the bottom of the heat treatment sample is placed In a liquid Ga-In alloy and connected with a drawing rod through a dovetail groove;
adjusting the distance between the induction coil and the liquid level of the liquid Ga-In alloy to ensure that an effective heat treatment area of the heat treatment sample is positioned In an effective heating range of the induction coil;
connecting the induction coil with an electrode, wherein the frequency of alternating current is 50kHz, and the heating temperature is more than 1500 ℃;
step four, closing a vacuum chamber door, starting a vacuum pump, pumping the air pressure in the vacuum chamber to be below 1Pa, then reversely filling high-purity argon into the vacuum chamber to 300Pa, repeating the operation for 3-5 times, and finally ensuring that the directional heat treatment experiment is carried out under the protection of the argon gas with the pressure of less than 1 Pa;
step five, closing a power supply, and increasing the loading power of the induction coil in a stepping manner, and simultaneously increasing the temperature of an effective heat treatment area of the heat treatment test bar;
step six, when the temperature of the effective heat treatment area reaches the temperature range of the beta single-phase area of the heat treatment test bar, stopping adjusting the loading power of the induction coil and keeping the temperature for 5-20 min;
step seven, starting the drawing device, setting the directional drawing speed of the heat treatment test bar to be 0.01mm/min-1.00mm/min through a speed regulator, and carrying out directional heat treatment on the heat treatment test bar;
and step eight, after the treatment is finished, reducing the loading power, introducing air into the vacuum chamber after the heat treatment test bar is cooled to room temperature, and taking out the test bar subjected to the directional heat treatment to obtain the directionally arranged columnar crystal structure.
Compared with the prior art, the invention has the following effects:
1. the invention can be suitable for common cast TiAl-based alloy without thermal deformation treatment, the prepared Ti44Al6Nb1Cr alloy with the oriented columnar crystal structure has the tensile strength of 636MPa and the total strain of 2.28 percent, and compared with the mechanical property of the alloy after oriented solidification (523MPa,3.03 percent), the tensile strength is improved by 22 percent.
2. The invention utilizes a heat treatment mode, leads beta crystal grains to directionally grow under the action of directional heat flow through solid-state phase transition, and the transverse crystal boundary spontaneously migrates, thereby avoiding the surface layer of the sample from easily generating lateral heat dissipation, finally obtaining a columnar crystal structure in directional arrangement, effectively avoiding the TiAl-based alloy melt from contacting with a crucible or a coating material to influence the directional growth of alloy chemical components and crystal grains, and reducing energy consumption.
3. After the directional heat treatment is adopted, as the temperature of the effective heat treatment area of the TiAl-based alloy test bar is ensured to be within the temperature range of a beta single-phase area in the sixth step and the seventh step, and the directional growth of crystal grains can be ensured by setting a proper drawing speed, the directional growth of the crystal grains is ensured, so that the directional arrangement of columnar crystal structures is obtained, the lamellar clusters are changed into columns from ellipsoids, the B2 phase is changed into strips from a net shape, the directionality of the microstructure of the TiAl-based alloy is obviously improved, and the specific performance is improved: the lamellar clusters in the alloy microstructure are changed into columnar shape after the directional heat treatment from original ellipsoid shape, the B2 phase is changed into strip shape from net shape, compared with the common cast alloy, the tensile strength of the alloy after the directional heat treatment is greatly improved, and the total strain is also improved, namely the performance in the table 1.
4. Compared with the directionally solidified Ti44Al6Nb1Cr alloy, the tensile strength of the alloy after the directional heat treatment reaches 636MPa, and the total strain is 2.28%. Compared with the Ti44Al6Nb1Cr alloy prepared by directional solidification, the tensile strength is improved by 22 percent.
Drawings
FIG. 1 is a schematic view of a directional heat treatment device for a beta-solidified TiAl-based alloy, which is used for obtaining a directionally arranged columnar crystal structure by adjusting the loading power of an induction coil, the distance between the induction coil and a Ga-In liquid alloy, the movement rate of a drawing rod, and controlling the temperature, the directional heat flow, the temperature gradient and the interface continuous migration of an effective heat treatment area of a test bar.
FIG. 2 is a macroscopic structure view of the Ti44Al6Nb1Cr alloy of the example before and after directional heat treatment in (a) an as-cast state, (b) a directionally solidified state, and (c) a directionally heat treated state.
FIG. 3 is a microstructure of the Ti44Al6Nb1Cr alloy of the examples before and after the directional heat treatment, wherein (a) is in an as-cast state, (b) is in a directionally solidified state, and (c) is in a directionally heat-treated state.
Detailed Description
The first embodiment is as follows: the present embodiment will be described with reference to fig. 1, and an apparatus for manufacturing an oriented TiAl-based alloy using solid-state phase transition according to the present embodiment includes a vacuum chamber 1; the device also comprises a liquid Ga-In alloy 2, a speed regulator 3, an induction coil 4, a thermodetector 5, a heat treatment test rod 6 and an Ar gas cylinder 7, wherein the liquid Ga-In alloy 2 is positioned at the lower part In the vacuum chamber 1, the heat treatment test rod 6 is vertically arranged In the vacuum chamber 1, the speed regulator 3 is arranged at the bottom end of the heat treatment test rod 6 In a dovetail groove connection mode and regulates and controls the pull-down speed of the heat treatment test rod 6 In real time, the wire end of the thermodetector 5 extends into the vacuum chamber 1 and is positioned In an effective heat treatment area 8, wherein a wire of the thermodetector is independently led out from the furnace, and an external power supply is constant-pressure 220V; the induction coil is provided with an independent power supply, the power supply is 380V, the induction coil 4 is sleeved on the outer side of the upper part of the heat treatment test bar 6 and heats an effective heat treatment area 8 on the heat treatment test bar 6, and the Ar gas cylinder 7 is connected with the vacuum chamber 1.
The heat treatment test bar 6 and the speed regulator 3 are connected in a dovetail groove mode, the speed regulator can be guaranteed to regulate and control the lower drawing speed of the heat treatment test bar 6 in real time, and the regulating range of the speed regulator 3 is 0.01mm/min-1.0 mm/min.
The second embodiment is as follows: the present embodiment will be described with reference to fig. 1, and the adjustment range of the speed governor 3 of the present embodiment is 0.01mm/min to 1.0 mm/min. So set up, adjust the precision height. Other components and connections are the same as in the first embodiment.
The heat treatment test bar 6 and the speed regulator 3 are connected in a dovetail groove manner, so that the speed regulator can regulate and control the lower drawing speed of the heat treatment test bar 6 in real time, and the regulating range of the speed regulator 3 is 0.01mm/min-1.0 mm/min; the induction coil 4 is made of red copper, the heat treatment test bar 6 can be heated to 1280-1690 ℃ locally, the liquid Ga-In alloy 2 can cool the heat treatment test bar 6 to 100-600 ℃, and thus the heat treatment test bar 6 can be ensured to form the required temperature gradient; the temperature measuring instrument 5 can monitor the temperature change of the heat treatment test bar 6 heated by the induction coil 4 in real time, and the temperature measuring precision is +/-10 ℃; the length, the width and the height of the vacuum chamber 1 are 800mm, 700mm and 1200mm, so that the method for directionally preparing the TiAl alloy can be realized; the purity of the argon in the Ar gas bottle 7 is 99.9999 percent, the oxygen content in the vacuum chamber 1 can be ensured to be lower, and the whole preparation process is carried out under the protection of inert gas argon.
The third concrete implementation mode: referring to fig. 1, the present embodiment is described, and a method for preparing an oriented TiAl-based alloy using solid-state phase transformation according to the present embodiment includes the steps of:
step one, In a vacuum chamber 1, placing a beta-solidified TiAl-based alloy heat treatment sample 6 In a five-turn induction coil 4, so that the axis of the heat treatment sample 6 is completely superposed with the central line of the induction coil 4, and the bottom of the heat treatment sample 6 is placed In a liquid Ga-In alloy 2 and connected with a drawing rod through a dovetail groove;
step two, adjusting the distance between the induction coil 4 and the liquid level of the liquid Ga-In alloy 2 to ensure that an effective heat treatment area 8 of the heat treatment sample 6 is positioned In the effective heating range of the induction coil 4;
connecting the induction coil 4 with an electrode, wherein the frequency of alternating current is 50kHz, and the heating temperature is more than 1500 ℃;
step four, closing a door of the vacuum chamber 1, starting a vacuum pump, pumping the air pressure in the vacuum chamber 1 to be below 1Pa, then reversely filling high-purity argon into the vacuum chamber 1 to 300Pa, repeating the operation for 3-5 times, and finally ensuring that the directional heat treatment experiment is carried out under the protection of the argon gas with the pressure of less than 1 Pa;
step five, closing a power supply, and increasing the loading power of the induction coil 4 in a stepping manner, and simultaneously increasing the temperature of the effective heat treatment area 8 of the heat treatment test bar 6;
step six, when the temperature of the effective heat treatment area 8 reaches the temperature range of the beta single-phase area of the heat treatment test bar 6, stopping adjusting the loading power of the induction coil 4 and keeping the temperature for 5-20 min;
step seven, starting the drawing device, setting the directional drawing speed of the heat treatment test bar 6 to be 0.01mm/min-1.00mm/min through the speed regulator 3, and carrying out directional heat treatment on the heat treatment test bar;
and step eight, after the treatment is finished, reducing the loading power, introducing air into the vacuum chamber 1 after the heat-treated test bar 6 is cooled to room temperature, and taking out the test bar subjected to the directional heat treatment to obtain the directionally arranged columnar crystal structure.
The temperature measuring instrument 5 of the present embodiment can monitor the temperature change of the heat treatment test bar 6 heated by the induction coil 4 in real time, and the temperature measuring precision is ± 10 ℃.
The fourth concrete implementation mode: the present embodiment will be described with reference to FIG. 1. the heat-treated test bar 6 in the first step of the present embodiment is a TiAl-based alloy sample, preferably a Ti44Al6Nb1Cr alloy, having a cross-sectional diameter of 15mm to 25mm, preferably 20 mm. Other compositions and connection relationships are the same as in the first, second or third embodiment.
The fifth concrete implementation mode: referring to fig. 1, the heat treatment bar 6 of the present embodiment is placed In a pool of liquid Ga-18 at.% In alloy 2, and the temperature of the liquid Ga-18 at.% In alloy 2 is constant at 25 ℃. This ensures that the test bar 6 is subjected to downward heat conduction during the directional heat treatment. Other compositions and connection relationships are the same as those in the first, second, third or fourth embodiment.
The sixth specific implementation mode: referring to FIG. 1, the heat treatment test bar 6 in the third step of the present embodiment is heated by the induction coil 4, the effective heat treatment zone 8 is within the range of 10mm-15mm in the vertical direction of the heat treatment test bar 6, and the heating temperature can reach 1500 ℃ or higher, so that the temperature of the effective heat treatment zone 8 is within the range of the beta single-phase zone of the beta-solidified TiAl-based alloy during the directional heat treatment. By the arrangement, grains in the effective heat treatment area of the test bar grow spontaneously, and grain boundaries continuously migrate under the action of directional heat flow. Other compositions and connection relationships are the same as in the first, second, third, fourth or fifth embodiment.
The seventh embodiment: referring to FIG. 1, the present embodiment will be described, wherein the induction coil 4 In the third step of the present embodiment is made of red copper, the temperature for locally heating the heat-treated test bar 6 is 1280 to 1690 ℃, and the temperature for cooling the heat-treated test bar 6 by the liquid Ga-In alloy 2 is 100 to 600 ℃. So set up, can guarantee that heat treatment test bar 6 forms required temperature gradient. Other compositions and connection relationships are the same as in the first, second, third, fourth, fifth or sixth embodiment.
The specific implementation mode eight: the present embodiment will be described with reference to fig. 1, and the dimensions of the vacuum chamber 1 in the first step of the present embodiment are 800mm × 700mm × 1200mm in length × width × height. By the arrangement, the method for directionally preparing the TiAl alloy can be realized. Other compositions and connection relationships are the same as in the first, second, third, fourth, fifth or sixth embodiment.
The specific implementation method nine: in the present embodiment, the argon purity of the high-purity argon gas in the Ar gas cylinder 7 of the present embodiment is 99.9999% as described with reference to fig. 1. By such arrangement, the oxygen content in the vacuum chamber 1 can be ensured to be lower, and the whole preparation process is carried out under the protection of inert gas argon. Other compositions and connection relationships are the same as in the first, second, third, fourth, fifth or sixth embodiment.
Example (b):
the invention relates to a device for preparing oriented TiAl-based alloy by utilizing solid phase transition, which structurally comprises a vacuum chamber 1, a liquid Ga-In alloy 2, a speed regulator 3, an induction coil 4, a temperature measuring instrument 5, a heat treatment test rod 6, an Ar gas cylinder 7 and an effective heat treatment area 8; the heat treatment test bar 6 is connected with the speed regulator 3 in a dovetail groove mode, the speed regulator can regulate and control the lower drawing speed of the heat treatment test bar 6 in real time, and the regulating range of the speed regulator 3 is 0.01mm/min-1.0 mm/min; the induction coil 4 is made of red copper, the heat treatment test bar 6 can be heated to 1280-1690 ℃ locally, the liquid Ga-In alloy 2 can cool the heat treatment test bar 6 to 100-600 ℃, and thus the heat treatment test bar 6 can be ensured to form the required temperature gradient; the temperature measuring instrument 5 can monitor the temperature change of the heat treatment test bar 6 heated by the induction coil 4 in real time, and the temperature measuring precision is +/-10 ℃; the length, the width and the height of the vacuum chamber 1 are 800mm, 700mm and 1200mm, so that the method for directionally preparing the TiAl alloy can be realized; the purity of the argon in the Ar gas bottle 7 is 99.9999 percent, the oxygen content in the vacuum chamber 1 can be ensured to be lower, and the whole preparation process is carried out under the protection of inert gas argon.
The invention relates to a preparation method for preparing oriented TiAl-based alloy by utilizing solid-state phase transition, which comprises the following process steps:
step one, In a vacuum chamber 1, placing a beta-solidified TiAl-based alloy heat treatment sample 6 In a five-turn induction coil 4, so that the axis of the treatment sample 6 is completely overlapped with the central line of the induction coil 4, and the bottom of the treatment sample 6 is placed In a liquid Ga-In alloy 2 and connected with a drawing rod through a dovetail groove;
step two, adjusting the distance between the induction coil 4 and the liquid level of the Ga-In alloy 2 to ensure that the effective heat treatment area of the heat treatment sample 6 is positioned In the effective heating range of the induction coil 4;
connecting the induction coil 4 with an electrode, wherein the frequency of alternating current is 50kHz, the range of the effective heating treatment area 8 for heating is 10-15 mm, and the heating temperature can reach more than 1500 ℃;
step four, closing a door 1 of the vacuum chamber, starting a vacuum pump, pumping the air pressure in the vacuum chamber to be below 1Pa, then reversely filling high-purity argon gas into the vacuum chamber for 7-300 Pa, repeating the operation for 3-5 times, and finally ensuring that the directional heat treatment experiment is carried out under the protection of the argon gas with the pressure of less than 1 Pa;
step five, closing a power supply, increasing the loading power of the induction coil 4 in a stepping mode, and measuring the temperature of an effective heating area of the sample 6;
step six, when the temperature of the effective heat treatment area of the sample reaches the temperature range of the beta single-phase area of the TiAl-based alloy 6, stopping adjusting the loading power of the induction coil 4 and keeping the temperature for 5-20 min;
step seven, starting the drawing device, setting the directional drawing speed of the test bar to be 0.01mm/min-1.00mm/min, preferably 0.25mm/min through the speed regulator 3, and carrying out directional heat treatment on the TiAl-based alloy test bar 6;
and step eight, after the treatment is finished, quickly reducing the loading power, introducing air into the vacuum chamber 1 after the test bar 6 is cooled to room temperature, and taking out the test bar 6 subjected to the directional heat treatment to obtain the directionally arranged columnar crystal structure.
The macroscopic structure is shown in figure 2, the as-cast TiAl alloy is in the shape of equiaxed crystals as shown in figure 2a, the directionally solidified microstructure shown in figure 2b has columnar crystals but has poor directional effect and discontinuous columnar crystal growth, and figure 2c is the large-size continuously grown columnar crystal microstructure obtained by the invention patent, and the columnar crystals which are obviously directionally arranged can be seen. The microstructure is shown in fig. 3, the orientation of the microstructure of the Ti44Al6Nb1Cr alloy is obviously improved, and the microstructure under the back scattering condition of fig. 3 shows that the growth direction of the tissue lamellar cluster obtained by the invention patent is basically parallel to the direction of the temperature gradient, and the orientation of the lamellar cluster is consistent. The room temperature tensile property of the alloy is shown in table 1, and the mechanical property of the alloy obtained by the preparation method and the device for preparing the oriented TiAl-based alloy by utilizing solid-state phase transition is greatly improved, the room temperature tensile strength of the oriented TiAl-based alloy obtained by the invention is 636MPa, the total strain is 2.28 percent, and the tensile strength is improved by 22 percent compared with the mechanical property of the alloy after oriented solidification (523MPa,3.03 percent).
TABLE 1 mechanical Properties of Ti44Al6Nb1Cr alloy in different states
Claims (8)
1. A method for preparing an oriented TiAl-based alloy by utilizing a device for preparing the oriented TiAl-based alloy by solid-state phase transition is characterized by comprising the following steps:
the device for preparing the directional TiAl-based alloy by solid-state phase transition comprises a vacuum chamber (1), a liquid Ga-In alloy (2), a speed regulator (3), an induction coil (4), a thermodetector (5), a heat treatment test bar (6) and an Ar gas cylinder (7), the liquid Ga-In alloy (2) is positioned at the lower part In the vacuum chamber (1), the heat treatment test bar (6) is vertically arranged In the vacuum chamber (1), the speed regulator (3) is arranged at the bottom end of the heat treatment test bar (6) In a dovetail groove connection mode and regulates and controls the pull-down speed of the heat treatment test bar (6) In real time, the wire end of the temperature measuring instrument (5) extends into the vacuum chamber (1) and is positioned In an effective heat treatment area (8), the induction coil (4) is sleeved at the outer side of the upper part of the heat treatment test bar (6) and heats the effective heat treatment area (8) on the heat treatment test bar (6), and the Ar gas cylinder (7) is connected with the vacuum chamber (1);
the method for preparing the oriented TiAl-based alloy comprises the following steps:
firstly, In a vacuum chamber (1), placing a TiAl-based alloy heat treatment test bar (6) solidified by beta In an induction coil (4) with five turns so that the axis of the heat treatment test bar (6) is completely coincided with the central line of the induction coil (4), and placing the bottom of the heat treatment test bar (6) In a liquid Ga-In alloy (2) and connecting the heat treatment test bar with a drawing rod through a dovetail groove;
adjusting the distance between the induction coil (4) and the liquid level of the liquid Ga-In alloy (2) to ensure that an effective heat treatment area (8) of the heat treatment test bar (6) is positioned In the effective heating range of the induction coil (4);
connecting the induction coil (4) with an electrode, wherein the frequency of alternating current is 50kHz, and the heating temperature is more than 1500 ℃;
step four, closing a door of the vacuum chamber (1), starting a vacuum pump, pumping the air pressure in the vacuum chamber (1) to be below 1Pa, then reversely filling high-purity argon into the vacuum chamber (1) to 300Pa, repeating the operation for 3-5 times, and finally ensuring that the directional heat treatment experiment is carried out under the protection of the argon gas with the pressure of less than 1 Pa;
step five, closing a power supply, and increasing the loading power of the induction coil (4) in a stepping manner, and simultaneously increasing the temperature of an effective heat treatment area (8) of the heat treatment test bar (6);
step six, when the temperature of the effective heat treatment area (8) reaches the temperature range of the beta single-phase area of the heat treatment test bar (6), stopping adjusting the loading power of the induction coil (4) and keeping the temperature for 5-20 min;
step seven, starting a drawing device, setting the directional drawing speed of the heat treatment test bar (6) to be 0.01mm/min-1.00mm/min through a speed regulator (3), and carrying out directional heat treatment on the heat treatment test bar;
and step eight, after the treatment is finished, reducing the loading power, introducing air into the vacuum chamber (1) after the test bar (6) to be subjected to heat treatment is cooled to room temperature, and taking out the test bar subjected to directional heat treatment to obtain the directionally arranged columnar crystal structure.
2. The method for preparing the oriented TiAl-based alloy by using the apparatus for preparing the oriented TiAl-based alloy by solid-state phase transition as claimed in claim 1, wherein: the heat treatment test bar (6) in the first step is a TiAl-based alloy test sample, and the cross-sectional diameter size of the test bar is 15mm-25 mm.
3. The method for preparing the oriented TiAl-based alloy by using the apparatus for preparing the oriented TiAl-based alloy by solid-state phase transition as claimed in claim 2, wherein: the heat treatment bar (6) was placed In a pool of liquid Ga-18 at.% In alloy (2), the temperature of the liquid Ga-18 at.% In alloy (2) being constantly 25 ℃.
4. The method for preparing the oriented TiAl-based alloy by using the apparatus for preparing the oriented TiAl-based alloy by solid-state phase transition as claimed in claim 3, wherein: the heating mode of the heat treatment test bar (6) in the third step is that the induction coil (4) is heated, the range of the effective heat treatment area (8) is 10mm-15mm in the vertical direction of the heat treatment test bar (6), the heating temperature is more than 1500 ℃, and the temperature of the effective heat treatment area (8) is ensured to be in the range of a beta single-phase area of the beta-solidified TiAl-based alloy in the directional heat treatment process.
5. The method for preparing the oriented TiAl-based alloy by using the apparatus for preparing the oriented TiAl-based alloy by solid-state phase transition as claimed in claim 4, wherein: the induction coil (4) In the third step is made of red copper, the local heating temperature of the heat treatment test bar (6) reaches 1280-1690 ℃, and the temperature of the liquid Ga-In alloy (2) to the heat treatment test bar (6) is cooled to 100-600 ℃.
6. The method for preparing the oriented TiAl-based alloy by using the apparatus for preparing the oriented TiAl-based alloy by solid-state phase transition as claimed in claim 5, wherein: the size of the vacuum chamber (1) in the first step is 800mm, 700mm and 1200mm in length, width and height.
7. The method for preparing the oriented TiAl-based alloy by using the apparatus for preparing the oriented TiAl-based alloy by solid-state phase transition as claimed in claim 6, wherein: the argon purity of the high-purity argon in the Ar gas cylinder (7) is 99.9999%.
8. The method for preparing the oriented TiAl-based alloy by using the apparatus for preparing the oriented TiAl-based alloy by solid-state phase transition according to claim 1, wherein: the adjusting range of the speed regulator (3) is 0.01mm/min-1.0 mm/min.
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