Method for preparing or orienting single-crystal high-temperature alloy based on seed crystal
By setting an angle control section between the crystal selector and the part, secondary orientation control of the bottom seed crystal is solved, and the complexity and cost problems of the preparation of <110> and <111> orientation single crystal high-temperature alloys in the prior art are solved. , realizes efficient and controllable single crystal alloy preparation, and improves mechanical properties and production efficiency.
Patent Information
- Application Number
- CN202411240389.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-05
- Publication Date
- 2024-12-20
AI Technical Summary
The prior art is difficult to effectively prepare single crystal high-temperature alloys with excellent mechanical properties, and there are problems such as complex operation, high cost, poor accuracy and miscellaneous crystals.
By setting an angle control section between the crystal selector and the part, the bottom seed crystal is controlled by secondary orientation, and a single crystal high-temperature alloy with <110> and <111> orientation is prepared, simplifying the preparation process , reduces production costs and improves orientation controllability.
It realizes efficient preparation of <110> and <111> orientation single crystal high-temperature alloys, reduces the probability of occurrence of hetero crystal defects, improves mechanical properties and production efficiency, and is suitable for batch production and engineering applications.
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Figure CN119162644A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of single crystal high temperature alloy preparation, and in particular to a <110> , <111> Preparation method of special oriented single crystal high-temperature alloy. Background Art
[0002] Nickel-based single crystal superalloys are widely used in the manufacture of turbine blades for advanced aero engines, ships and ground industrial gas turbines due to their excellent high temperature performance. Due to the elimination of grain boundaries, the mechanical properties of single crystal superalloys show significant anisotropy. <001> The elastic modulus in the direction is low and has better comprehensive performance. However, in order to improve the mechanical properties of specific parts of single crystal blades and meet the needs of scientific research and production, it is necessary to prepare <110> , <111> Oriented single crystal high temperature alloy. Therefore, how to prepare <110> , <111> Oriented single crystal high-temperature alloys have become a technical problem that needs to be solved at present.
[0003] In the previously disclosed inventions, the following two methods are commonly used to prepare special oriented single crystal high temperature alloys: (1) seed crystal cutting method; first, the single crystal orientation is determined by X-rays; then, a special tool is used to rotate the single crystal at a specific angle to cut the existing single crystal; finally, the obtained seed crystal is used to obtain a special high temperature alloy by epitaxial growth. <110> , <111> Oriented single crystal high temperature alloy. The preparation method of this kind of special oriented single crystal high temperature alloy has a series of problems such as complex operation, high cost, poor precision and dendrite cutting. (2) Seed crystal and mold shell inclination shell method; Due to the large shell angle, random errors are inevitable in the preparation and embedding of seed crystals, affecting the orientation accuracy; Furthermore, in the process of directional solidification, three dendrites need to develop into one dendrite to grow upward, which is very easy to produce impurities and it is difficult to ensure the single crystal nature of the alloy; In addition, the dendrites are approximately linearly distributed. When the orientation deviation angle is large, the inhomogeneity of the solidification structure promotes the initiation of cracks, which seriously reduces the key properties of the alloy such as high temperature creep and fatigue, which is not conducive to the development and application of special oriented single crystal high temperature alloys.
[0004] Therefore, in view of the above technical problems, the present invention proposes a method based on <001> Seed crystal acquisition <110> , <111> A method for preparing an oriented single crystal high temperature alloy, that is, by setting an angle control section between a crystal selector and a part to control the secondary orientation of a bottom seed crystal, <110> , <111> Oriented single crystal high temperature alloy. This invention not only simplifies the seed crystal preparation process, reduces production costs, and improves the production efficiency of single crystal castings, but also has better operability and better orientation controllability. Summary of the invention
[0005] In order to overcome the shortcomings and deficiencies of the prior art, the present invention aims to provide a <001> Seed crystal preparation <110> or <111> Method for orienting single crystal high temperature alloy. <110> , <111> Oriented single crystal high temperature alloy has a simple process and low cost, and can meet the needs of mass production and engineering application. To this end, the present invention provides the following technical solution, and the specific steps are as follows:
[0006] (1) Preparation of single crystal high temperature alloy seed crystal segments;
[0007] Seed crystal cutting: Cut the seed crystal segment on the nickel-based single crystal high-temperature alloy substrate (the normal line of the cutting surface is <001> growth direction, the cutting surface is (001) plane), or a single crystal test rod prepared by the spiral crystal selection method (the normal line of its end face is <001> Growth direction, the end face is (001) plane) as the seed crystal segment.
[0008] Grinding and etching: as shown Figure 1 As shown, the (001) surface is the surface to be processed, and 400#, 1000#, and 2000# sandpapers are used in sequence to perform mechanical grinding on a water mill in alternating 90° (grinding direction), wherein the scratches are uniform and in the same direction as the standard for sandpaper replacement, and then polishing is performed. The seed crystal after grinding and polishing is etched using a corrosive agent, and generally the etching standard is to observe a "cross flower" clearly visible to the naked eye.
[0009] Calibration of secondary orientation: by schematic Figure 1 It can be seen that <001> The cross section of the seed crystal is a typical "cross flower" shape, and the secondary dendrites are <010> and <100> Oriented growth (i.e., cross-direction), according to <010> and <100> Perform secondary orientation calibration and draw on the (001) plane Figure 1 The cross shown in the figure is sufficient.
[0010] (2) wax pattern assembly and mold shell preparation;
[0011] The wax mold is assembled according to the conventional spiral crystal selector mold shell preparation process: the wax mold is divided into a riser, a runner, a part (the part to be cast), an angle control section (such as Figure 2 The wax mold is assembled by connecting the parts of the wax mold with the crystal selection section, the seed crystal section and the chassis. The wax mold is evenly coated with ceramic refractory slurry, and then dewaxed and sintered in sequence to obtain the mold shell. Figure 3 shown.
[0012] (3) Seed crystal embedding;
[0013] The seed crystal is embedded in a mold shell with an angle control section of 45°, ensuring that the seed crystal section ((001) plane is parallel to the horizontal plane, where 45° is the angle between the axial direction of the part and the horizontal direction) and the seed crystal is <100> or <010> Secondary orientation and part axial <001> The projection line in the direction is parallel (such as Figure 4 As shown), the seed crystal is fixed by using a mixed solution of corundum and silica sol.
[0014] (4) Casting of high temperature alloys;
[0015] The high temperature alloy master alloy melt is poured into the mold shell for directional solidification, and the secondary orientation of the bottom seed crystal is controlled by the angle control section to obtain the <110> Oriented single crystal high temperature alloy, as shown in the figure Figure 5 shown.
[0016] (5) Orientation determination and secondary orientation calibration.
[0017] The above results were analyzed by Laue method. <110> Oriented seed crystals are oriented and calibrated for secondary orientation, such as Figure 6 shown.
[0018] (6) <111> Seed crystal preparation
[0019] The income <110> The secondary orientation of the seed crystal is calibrated according to step 5, and then buried in a mold shell with a control section angle of 33° (where 33° is the angle between the axial direction and the horizontal direction of the part) according to the seed crystal embedding requirements, and then high-temperature alloy casting is completed. <111> Preparation of oriented single crystal high temperature alloy, as shown in the figure Figure 7 shown.
[0020] Preferably, the seed crystal axis is <001> The deviation angle of direction should be controlled within 5°.
[0021] Preferably, the corrosive agent is a copper sulfate hydrochloric acid aqueous solution, the ratio of which is 4g CuSO4+10ml HCl+20ml H2O; wherein copper sulfate is Cu S O4·5H2O, the mass concentration of hydrochloric acid is 36% to 38%.
[0022] Preferably, the inner cavity of the seed crystal section is a cylindrical cavity, which is sequentially connected with the crystal selection section and the angle control section with a smooth transition.
[0023] Preferably, the lower end face of the angle control section is a square, the upper end face is a rectangle, the lower end face is parallel to the horizontal plane, the upper end face and the lower end face form an angle of 45° or 57°, the upper part of the angle control section in the projection of the vertical plane parallel to the long side of the rectangle is a right triangle, and the lower part is a right trapezoid with an upper base length greater than a lower base length, one right-angled side of the right triangle is collinear with the right-angled side of the right trapezoid, and the other right-angled side of the right triangle coincides with the upper base of the right trapezoid;
[0024] Preferably, the side length of the square of the lower end face is 5-8mm (preferably 5.5-6.5mm), the length of the rectangle of the upper end face is 12-18mm (preferably 13-15mm), and the width is 3-5mm (preferably 3.5-4.5mm). The vertical distance between the highest point of the upper end and the lower end face, that is, the height of the angle control section, is 15-25mm (preferably 18-22mm). The inner cavity of the angle control section is a chamber formed by a gradual and smooth transition from the square of the lower end face to the rectangle of the upper end face. The corners are rounded during the smooth transition process, and the fillet radius R=1.5-2.5 (preferably 1.8-2.2); the upper and lower end faces of the angle control section are connected to the parts and the crystal selection section through a smooth transition section. For details, refer to Figure 2 .
[0025] Preferably, the lower end face of the angle control section is connected to the upper end face of the vertical section of the crystal selection section in the spiral crystal selector through a transition section, the inner cavity of the upper end face of the vertical section of the crystal selector is a circle with a diameter of 4 to 6 mm (preferably 4.5-5.5 mm), the two transition smoothly, the length (or height) of the transition section between their two end faces is 1 to 10 mm (preferably 2-4 mm), and the inner cavity of the transition section gradually and smoothly transitions from the lower end face of the angle control section to the upper end face of the crystal selection section;
[0026] The upper end face of the angle control section is connected to the lower end face of the part (casting cavity to be cast) through the transition section. The part is a cylindrical cavity with a lower end face diameter of 12-36mm (preferably 13-15mm). The length (or height) of the transition section between their two end faces is 10-25mm (preferably 18-22mm). The inner cavity of the filter section gradually and smoothly transitions from the upper end face of the angle control section to the lower end face of the part; the transition section is chamfered, R=1.5~2.5 (preferably 1.5-1.6).
[0027] Preferably, an angle control section is provided between the crystal selector and the part, and the angles of the control section are 45° and 33° respectively. After the angle control section is adjusted, the angles between the axial direction of the part and the horizontal direction are ensured to be 45° and 33° respectively, and are used for <110> , <111> Preparation of oriented single crystal high temperature alloys.
[0028] Preferably, the dewaxing temperature is 200-500°C (preferably 400-450°C).
[0029] Preferably, the sintering temperature is 750-1100° C. (preferably 1000-1050° C.) and the sintering time is 8-12 hours.
[0030] Preferably, the secondary orientation of the seed crystal is in accordance with the axial <001> The projection line of the direction is parallel.
[0031] Preferably, the seed crystal segment is fixed with a mixture of corundum powder and silica sol, the particle size of the corundum powder is 300-400 mesh, the mass ratio of powder to liquid is 2.8-3.6:1.5-2.2 (preferably 3:1.8). The mass content of SiO2 in silica sol is 30-40% (preferably 35%);
[0032] Preferably, the pouring temperature of the high temperature alloy is 1500-1600°C.
[0033] Preferably, the directional solidification pulling rate is 1 to 5 mm / min.
[0034] Preferably, the X-ray test parameters are voltage 41 kV, 0.35 mA.
[0035] Preferably, the test is performed along the radial direction of the obtained single crystal high-temperature alloy casting.
[0036] Preferably, the single crystal rod is rotated along the radial direction to rotate the single crystal rod to the position where γ≈45°; β≈45°; α=Min, as shown in the figure Figure 6 As shown. Among them, the direction perpendicular to the ray source is <001> The secondary orientation, parallel to the ray source is <110> Secondary orientation.
[0037] The advantage of the present invention is that the secondary orientation of the bottom seed crystal is controlled by setting an angle control section between the crystal selector and the part, and the conventional <001> Seed crystal preparation <110> , <111> Oriented single crystal high temperature alloy. The angle control section is designed as a prism-shaped thin plate structure with a specific angle, which controls the secondary orientation of the bottom seed crystal and ensures that the single crystal high temperature alloy has a good temperature gradient in the directional solidification direction. <001> Seed crystal preparation <110> , <111> Oriented single crystal high-temperature alloys can also effectively reduce the probability of casting defects such as impurity crystals.
[0038] The advantages and beneficial technical effects of the present invention are described as follows:
[0039] (1) Compared with the existing seed crystal cutting preparation method, this preparation process is simple, fast, easy to operate, and does not require certain professional technical basic knowledge, which reduces the production cost of seed crystals and improves the production efficiency of seed crystals.
[0040] (2) The present invention provides <110> , <111> Oriented single crystal high temperature alloy has good as-cast structure inheritance and controllability of primary and secondary orientation. It can effectively improve the mechanical properties of specific parts of the blade, and in the process of directional solidification, the alloy cast later can <110> , <111> The continuous epitaxial growth of seed crystals is helpful for the preparation of single crystal blades with specific orientation. BRIEF DESCRIPTION OF THE DRAWINGS
[0041] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, a brief introduction will be given to the drawings required in the prior art description and the embodiments.
[0042] Figure 1 For face-centered cubic crystals <001> Axial schematic diagram;
[0043] Figure 2 Schematic diagram of the angle control section provided by the present invention; (1-part to be cast; 2-angle control section; 3-crystal selection section; 4-seed crystal section; 5-axial direction of the part to be cast <001> 6-the vertical projection line of the angle control section; 7-the width of the angle control section; 8-the thickness of the angle control section).
[0044] Figure 3 The directional solidification mold shell provided by the present invention;
[0045] Figure 4 for Figure 2 Schematic diagram of seed crystal embedding in the middle bottom; (9-the axial direction of the part to be cast is <001> Vertical projection line of the direction; 10-secondary orientation of dendrite).
[0046] Figure 5 For <001> Seed crystal preparation <110> Schematic diagram of the spatial relationship of oriented single crystal superalloy;
[0047] Figure 6 As shown in the embodiment <110> Schematic diagram of secondary orientation calibration of oriented single crystal high-temperature alloy; (11-casting to be tested; 12-sample stage; 13-black solid line represents the crystal coordinate system described relative to the reference coordinate system; 14-black dotted line represents the reference coordinate system; 15-X-ray source). Figure 7 For <110> Seed crystal preparation <111> Schematic diagram of the spatial relationship of oriented single crystal superalloy;
[0048] Figure 8 As described in the embodiment <110> (001) microstructure of oriented single crystal superalloy seed crystal;
[0049] Fig. 9 As described in the embodiment <110> (010) microstructure of oriented single crystal superalloy seed crystal;
[0050] Fig.10 As described in the embodiment <111> (001) microstructure of oriented single crystal superalloy seed crystal; DETAILED DESCRIPTION
[0051] The present invention provides a <001> Seed crystal preparation <110> or <111> The method for orienting a single crystal high temperature alloy comprises the following steps:
[0052] The present invention preferably <001> The orientation of the seed crystal is controlled within 5° (seed crystal <001> The axial angle between the surface and the cylindrical seed crystal is controlled within 5°, that is, <001> The orientation deviates within 5°), and is subjected to grinding, polishing and etching. The grinding and polishing is preferably carried out by mechanical grinding with 400#, 1000# and 2000# sandpaper in sequence, and then polishing with diamond grinding paste with a particle size of 2.5μm.
[0053] In the present invention, chemical etching is used as the etching method, and the etching liquid is a hydrochloric acid copper sulfate aqueous solution, and the ratio is 4gCuSO4+10ml HCl+20ml H2O, and the chemical etching time is controlled at 2-8s. After etching, a "cross flower" structure that is clear to the naked eye can be observed, and a cross line can be drawn parallel to the secondary dendrite axis.
[0054] The wax mold is assembled according to the conventional spiral crystal selector mold shell preparation process: the wax mold is divided into a riser, a runner, a part (casting to be cast), an angle control section (such as Figure 2 The wax mold is assembled by connecting the parts of the wax mold with the crystal selection section, the seed crystal section and the chassis. The wax mold is evenly coated with ceramic refractory slurry, and then dewaxed and sintered in sequence to obtain the mold shell. Figure 3 shown.
[0055] The inner cavity of the seed crystal section is a cylindrical cavity, which is connected with the crystal selection section and the angle control section from top to bottom.
[0056] The lower end face of the angle control section is a square, the upper end face is a rectangle, the lower end face is parallel to the horizontal plane, the upper end face and the lower end face form an angle of 45° (corresponding to a 45° mold shell) or 57° (corresponding to a 33° mold shell), the upper part of the projection of the angle control section parallel to the vertical plane of the long side of the rectangle is a right triangle, and the lower part is a right trapezoid with an upper base length greater than a lower base length, one right-angled side of the right triangle is collinear with the right-angled side of the right trapezoid, and the other right-angled side of the right triangle coincides with the upper base of the right trapezoid;
[0057] The side length of the square of the lower end face is 6mm, the length of the rectangle of the upper end face is 12mm and the width is 4mm. The vertical distance between the highest point of the upper end and the lower end face, that is, the height of the angle control section is 20mm. The inner cavity of the angle control section is a chamber formed by the gradual smooth transition from the square of the lower end face to the rectangle of the upper end face. The rounding treatment is performed during the smooth transition process, and the fillet radius R = 1.5 ~ 2.5; the upper and lower end faces of the angle control section are connected to the parts and the crystal selection section through the smooth transition section. For details, please refer to Figure 2 .
[0058] Preferably, the lower end face of the angle control section is connected to the upper end face of the vertical section of the crystal selection section in the spiral crystal selector through a transition section, the inner cavity of the upper end face of the vertical section of the crystal selector is a circle with a diameter of 5 mm, the two transition smoothly, the length (or height) of the transition section between their two end faces is 5 mm, and the inner cavity of the transition section gradually and smoothly transitions from the lower end face of the angle control section to the upper end face of the crystal selection section;
[0059] The upper end face of the angle control section is connected to the lower end face of the part (casting cavity to be cast) through the transition section. The part is a cylindrical cavity with a lower end face diameter of 13mm. The length (or height) of the transition section between their two end faces is 15mm, and the inner cavity of the transition section gradually and smoothly transitions from the upper end face of the angle control section to the lower end face of the part; the transition section is chamfered, R=1.5~2.5.
[0060] Preferably, the dewaxing temperature is 450°C.
[0061] Preferably, the sintering temperature is 1000° C. and the sintering time is 12 hours.
[0062] The present invention does not have any special limitation on the casting wax pattern material, and any material well known to those skilled in the art can be used.
[0063] The size of the wax mold can be preferably adjusted according to the actual needs of the target product.
[0064] The wax mold assembly of the present invention must ensure that the seed crystal segment <001> The axis forms an angle of 90° with the chassis; the angle between the crystal selector and the part is controlled by the angle control section, and the control angles are designed to be 45° and 33° respectively. There is no special limitation on the other combination processes, and the pouring system and the like can be mechanically combined using a process well known to those skilled in the art.
[0065] After the wax model is obtained, a ceramic refractory slurry is coated on the outside of the wax model, followed by dewaxing and calcining to obtain a shell. Figure 3 The mold shell comprises a riser, a runner, a part, an angle control section, a crystal selection section, a seed crystal section and a chassis from top to bottom.
[0066] After obtaining the mold shell, the seed crystal is embedded in the seed crystal section of the mold shell with a control angle of 45° (where 45° is the angle between the axial direction and the horizontal direction of the cylindrical part), and the secondary orientation of the seed crystal is ensured. <010> or <100> Orientation and casting <001> The vertical projection direction is parallel to the Figure 4 The resulting structure is shown in Figure 2), and then fixed with a mixed solution of corundum powder and silica sol.
[0067] The particle size of corundum powder is 300-400 mesh, and the mass ratio of powder to liquid is 3:1.8. The mass content of SiO2 in silica sol is 35%;
[0068] After the seed crystals are embedded, the present invention casts the melt of the high-temperature alloy master alloy into the mold shell for directional solidification to obtain the <110> Oriented single crystal high temperature alloy.
[0069] According to the above-mentioned seed crystal secondary orientation calibration requirements and seed crystal embedding requirements, the obtained <110> The oriented single crystal high temperature alloy seed crystal is buried in the seed crystal section of the mold shell with a control angle of 33° (where 33° is the angle between the axial direction and the horizontal direction of the cylindrical part), and ensure <110> Seed <110> Secondary orientation and casting <001> The projection line of the direction is parallel, and then the high-temperature alloy is cast and directional solidification is completed to obtain the above <111> Oriented single crystal high temperature alloy.
[0070] The present invention does not have any special limitation on the composition of the high-temperature alloy master alloy, and any alloy well known to those skilled in the art may be used.
[0071] The present invention does not have any special restrictions on the melting temperature, casting temperature, mold shell temperature, holding time and directional solidification pulling rate, and the crystal pulling process well known to those skilled in the art can be adopted.
[0072] The invention obtains a single crystal casting, adopts the Laue method to carry out primary orientation measurement and secondary orientation calibration.
[0073] The following is a description of the invention based on the embodiments. <001> Seed crystal acquisition <110> , <111> The preparation method of the oriented single crystal high temperature alloy is described, but it should not be understood as limiting the scope of protection of the present invention.
[0074] Embodiment 1:
[0075] Step 1: Preparation of high temperature alloy seed crystal segment:
[0076] Selection <001> A single crystal test rod with an orientation deviation of 2° was used as a cylindrical seed crystal, and one end face ((001) face) was used as the surface to be processed. It was mechanically ground using 400#, 1000#, and 2000# sandpapers in sequence, and polished using a diamond grinding paste with a particle size of 2.5μm. The seed crystal composition is Ni-6.8Cr-7.2Co-6.4Al-6.8Ta-4.8W-1.30Mo-3Re-0.12Hf (the number before the element represents its weight percentage in the alloy, and Ni is the balance).
[0077] Step 2: Calibration of secondary orientation:
[0078] The (001) surface was etched with the copper sulfate hydrochloric acid aqueous solution, and the clear cross observed by naked eyes was used as the standard, and the <100> and <010> Secondary orientation (ie, cross orientation). The etchant is a copper sulfate hydrochloric acid aqueous solution, with a ratio of 4g CuSO4+10ml HCl+20ml H2O; the copper sulfate is CuSO4·5H2O, and the mass concentration of hydrochloric acid is 37%.
[0079] Step 3: Seed crystal embedding:
[0080] The seed crystal is embedded in the seed crystal section of the mold shell (the directional solidification mold shell with a control angle of 45°), with the (001) plane parallel to the horizontal plane, and the seed crystal is ensured to be <100> or <010> The secondary orientation of the cylindrical part is <001> The vertical projection lines in the direction are parallel and fixed with a mixture of corundum and silica sol.
[0081] Step 4: Casting of high temperature alloy:
[0082] In this example, the high temperature alloy master alloy selected is Reńe N5 as the casting alloy, which is cast into the <110> In the mold shell, the pouring temperature of the high-temperature alloy is 1580°C, and after keeping warm for 15 minutes, directional solidification is carried out from bottom to top. The pulling rate of the directional solidification is 3mm / min, and the <110> Oriented single crystal high temperature alloy. The alloy composition is Ni-6.8Cr-7.2Co-6.4Al-6.8Ta-4.8W-1.30Mo-3Re-0.12Hf (the number before the element represents its weight percentage in the alloy, and Ni is the balance).
[0083] Step 5: Orientation determination of seed crystal casting:
[0084] The orientation of the obtained parts is measured using the Laue method, where the ray direction is the radial direction of the parts, and the position of the parts is adjusted radially during the test (for example, Figure 6When the α angle is the minimum value, the γ angle is the primary orientation value of the single crystal high temperature alloy, as shown in Table 1. The X-ray test parameters are voltage 41kV, 0.35mA.
[0085] Step 6: Calibration of secondary orientation of seed casting:
[0086] The obtained seed crystal casting is rotated along its radial direction, and the single crystal rod is rotated to the position of γ≈45°; β≈45°; α=Min, ensuring that the angle α is the minimum value, where the angle perpendicular to the ray direction is <001> The secondary orientation, parallel to the ray direction is <110> Secondary orientation, as shown Figure 6 shown.
[0087] Figure 8 and Fig. 9 Along the obtained <110> The (001) and (010) faces of the casting were cut, and the casting was polished and etched according to the above steps, and the resulting microstructure was observed. It was found that the crystal orientation of the single crystal high temperature alloy prepared by the method of the present invention is <110> Orientation, the orientation deviation is generally between 2 and 7°, the structure is uniform, there are no impurities, no casting defects, and it meets the requirements of industrial production.
[0088] Table 1 shows the Laue method test results of the three seed crystal castings obtained. Combined with formula (1), the crystal orientation index can be obtained. <uvw>= <110> ; Crystalline plane index <hkl>= <1-12>, it can be concluded that the casting provided by the present invention is <110> orientation.
[0089] Table 1 Laue method test results of the castings obtained in this embodiment
[0090] α β γ X-<100> Y-<010> Z-<001> Casting 1 -4 43.6 42.7 43.8 42.9 35.2 Casting 2 5.2 44.1 43.1 43.4 44.1 36.5 Casting 3 -7.3 -41.3 -42.4 44.6 38.2 37.2
[0091]
[0092] Step 7: <111> Preparation of oriented single crystal high temperature alloy:
[0093] Finish <110> After the secondary orientation calibration of the oriented single crystal high temperature alloy seed crystal, according to the above seed crystal processing requirements and seed crystal embedding requirements (process and conditions are the same as above <110> The preparation step 1-6 of the oriented single crystal high temperature alloy casting is different from that in that the seed crystal is buried in the obtained directional solidification mold shell with a control angle of 33°, and ensures that <110> Seed <110> Secondary orientation and cylindrical castings <001> The high temperature alloy is then cast and directional solidified from bottom to top. <110> The preparation method of the seed crystal can be analyzed and it can be known that the technical solution provided by the present invention can also be used to prepare <111> Oriented single crystal high temperature alloys generally have an orientation deviation of 2 to 10°, uniform structure, no impurities, no casting defects, and meet industrial production requirements. Figure 7 and Fig.10 shown.
[0094] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.< / hkl> < / uvw>
Claims
1. A method based on <001> Seed crystal preparation <110> or <111> The method for orienting single crystal high temperature alloys is to use a crystal selector in conjunction with a seeding section for operation, wherein the crystal selector includes, from top to bottom, a part to be cast (referred to as the part), a seeding section, a crystal selector section, and a seed crystal section; Features: The seeding section is an angle control section, which is used to adjust the secondary orientation of the bottom seed crystal. <110> or <111> Preparation of oriented single crystal high temperature alloys; The seed crystals are respectively embedded in the seed crystal segments of the mold shell with an angle control segment of 45° or 33°, and the (001) plane is parallel to the horizontal plane; wherein the 45° or 33° is the angle between the axial direction of the part and the horizontal direction; and the secondary orientation of the seed crystal is ensured <010> or <100> ,or <110> Secondary orientation and part axial <001> The vertical projection direction parallel to the direction can be prepared separately <110> or <111> Oriented single crystal high temperature alloy castings.
2. The method according to claim 1, characterized in that: The lower end face of the angle control section is a square, the upper end face is a rectangle, the lower end face is parallel to the horizontal plane, the upper end face and the lower end face form an angle of 45° or 57°, the upper part of the angle control section in the projection of the vertical plane parallel to the long side of the rectangle is a right triangle, and the lower part is a right trapezoid with an upper base length greater than a lower base length, one right-angled side of the right triangle is collinear with the right-angled side of the right trapezoid, and the other right-angled side of the right triangle coincides with the upper base of the right trapezoid; The side length of the square of the lower end face is 5~8mm, the length of the rectangle of the upper end face is 12~18mm, and the width is 3~6mm. The vertical distance between the highest point of the upper end and the lower end face, that is, the height of the angle control section is 15~25mm. The inner cavity of the angle control section is a chamber formed by a gradual and smooth transition from the square of the lower end face to the rectangle of the upper end face. Chamfering is performed during the smooth transition process, and the fillet radius R=1.5~2.5; the upper and lower end faces of the angle control section are connected to the parts and the crystal selection section through a smooth transition section.
3. The method according to claim 2, characterized in that: The lower end face of the angle control section is connected to the upper end face of the vertical section of the crystal selection section in the spiral crystal selector through a transition section. The inner cavity of the upper end face of the vertical section of the crystal selector is a circle with a diameter of 4-6 mm. The two transition smoothly. The length or height of the transition section between their two end faces is 1-10 mm. The inner cavity of the transition section gradually and smoothly transitions from the lower end face of the angle control section to the upper end face of the crystal selection section. The upper end face of the angle control section is connected to the lower end face of the part (casting cavity to be cast) through the transition section. The part is a cylindrical cavity with a lower end face diameter of 12-36 mm. The length or height of the transition section between their two end faces is 10~25mm. The inner cavity of the filter section gradually and smoothly transitions from the upper end face of the angle control section to the lower end face of the part; the transition section is chamfered, R=1.5~2.
5.
4. The method according to claim 1, 2 or 3, characterized in that: The process includes single crystal high temperature alloy seed crystal preparation, wax mold assembly and mold shell preparation, seed crystal embedding, and high temperature alloy casting; specifically, 1) Preparation of single crystal high temperature alloy seed crystal; 2) Wax model assembly and mold shell preparation; 3) Seed crystal embedding includes: <001> The seed crystal is embedded in the crystal selector mold shell with a control section angle of 45°, and ensure <010> or <100> Secondary orientation with the casting axial direction <001> The vertical projection line of the direction is parallel, and the high-temperature alloy is cast and directional solidified from bottom to top to obtain <110> Oriented single crystal high temperature alloy.
5. The method according to claim 4, characterized in that: a. Seed crystal orientation determination and secondary orientation calibration include: <110> Oriented single crystal high temperature alloys are subjected to primary orientation determination and secondary orientation calibration; b. <111> The preparation process of oriented single crystal high temperature alloy includes: <110> The seed crystal is embedded in a mold shell with a control section angle of 33°, and <110> Secondary orientation and part axial direction <001> The vertical projection line of the direction is parallel, and the high-temperature alloy is cast and directional solidified from bottom to top. <111> Preparation of oriented single crystal high temperature alloys.
6. The method according to claim 5, characterized in that: Seed crystal orientation determination and secondary orientation calibration: <110> The oriented single crystal high temperature alloy was subjected to primary orientation determination and secondary orientation calibration, where the seed crystal was measured in radial direction and the X-ray test parameters were voltage 40-45 kV, 0.30~0.40 mA; Among them, the seed crystal rotates along the radial direction. γ ≈45°; β ≈45°; α =Min; at this time, γ Angle is the primary orientation value of single crystal high temperature alloy; perpendicular to the direction of the radiation source is <001> The secondary orientation, parallel to the direction of the ray source is <110> Secondary orientation.
7. The method according to claim 4, characterized in that: The preparation of single crystal high temperature alloy seed crystals includes: cutting of seed crystals, mechanical grinding and polishing of seed crystals, chemical etching and determination of secondary orientation.
8. The method according to claim 4, characterized in that: The wax mold assembly and mold shell preparation include: the entire wax mold from top to bottom is respectively a riser, a runner, parts, an angle control section, a crystal selection section, a seed crystal section and a chassis, which are smoothly connected in sequence; then the outside of the above wax mold is evenly coated with ceramic refractory slurry, and then dewaxing and sintering are carried out in sequence to complete the preparation of the mold shell.