CN111733451A - Synchronous melting deposition-remelting elimination method for single crystal high-temperature alloy mixed crystal defects based on double-beam laser - Google Patents

Synchronous melting deposition-remelting elimination method for single crystal high-temperature alloy mixed crystal defects based on double-beam laser Download PDF

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CN111733451A
CN111733451A CN202010649845.9A CN202010649845A CN111733451A CN 111733451 A CN111733451 A CN 111733451A CN 202010649845 A CN202010649845 A CN 202010649845A CN 111733451 A CN111733451 A CN 111733451A
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laser
crystal
remelting
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CN111733451B (en
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雷正龙
卢楠楠
黎炳蔚
李鹏
胡宽
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Harbin Institute of Technology
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    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B19/00—Liquid-phase epitaxial-layer growth
    • C30B19/12—Liquid-phase epitaxial-layer growth characterised by the substrate
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B33—ADDITIVE MANUFACTURING TECHNOLOGY
    • B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
    • B33Y10/00—Processes of additive manufacturing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B33—ADDITIVE MANUFACTURING TECHNOLOGY
    • B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
    • B33Y50/00—Data acquisition or data processing for additive manufacturing
    • B33Y50/02—Data acquisition or data processing for additive manufacturing for controlling or regulating additive manufacturing processes
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B19/00—Liquid-phase epitaxial-layer growth
    • C30B19/10—Controlling or regulating
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
    • C30B29/10—Inorganic compounds or compositions
    • C30B29/52—Alloys
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B33/00—After-treatment of single crystals or homogeneous polycrystalline material with defined structure
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    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/25—Process efficiency

Abstract

A synchronous melting deposition-remelting elimination method of single crystal superalloy mixed crystal defects based on double-beam laser relates to the fields of 3D printing and superalloy preparation and repair. The invention aims to solve the problem of mixed crystals in the process of repairing single crystal high-temperature alloy. Compared with the common repairing method, the method can obviously improve the success rate and the repairing efficiency of the repairing of the single crystal. The method has great potential in repair of the single crystal blade and even direct additive manufacturing of the single crystal blade in the future. The invention is applied to the field of welding.

Description

Synchronous melting deposition-remelting elimination method for single crystal high-temperature alloy mixed crystal defects based on double-beam laser
Technical Field
The invention belongs to the field of 3D printing and high-temperature alloy preparation and repair, and particularly relates to a method for eliminating mixed crystal formation in a single-crystal high-temperature alloy repair process.
Background
The aero-engine is praised as a bright pearl on an industrial crown, has a great promoting effect on national economy and scientific and technological development, marks a national comprehensive national power, industrial foundation and scientific and technological level, and is an important strategic guarantee of national safety and the status of the greater country. Turbine gas turbines in aircraft engines, known as aircraft engine "hearts", are an important component of aircraft power. Currently, the most advanced single crystal superalloy blades have been used for the high pressure turbine blades of turbine gas turbines for most advanced aircraft engines. Generally, the working environment of a high-pressure turbine blade is the worst, the temperature of the high-pressure turbine blade is the highest, and the stress is the most complex, so that blade tip abrasion and erosion can occur in the service process, and the blade can not be continuously used and replaced due to the defects of cracks and the like. However, since the cost of the single crystal blade is extremely high and the replacement cost is extremely high, the repair technology for the damaged superalloy has been studied as a key technology in western developed countries, particularly in aviation countries.
At present, the repair means aiming at the single crystal superalloy blade generally adopts a laser melting deposition technology. The core problem for repairing single crystal superalloys is around how to obtain a structure based on the epitaxial growth of the parent material. Therefore, the solidification conditions need to be controlled by precisely controlling the process parameters, and finally, the columnar crystal structure epitaxially grown on the base material is obtained. The current process window for repairing single crystals is quite narrow, and to obtain epitaxially grown single crystal structures, precise control of process parameters is required to obtain a sufficiently large temperature gradient. In general, repair of single crystals is achieved by layer-by-layer deposition, wherein each layer is deposited without perfectly uniformly oriented columnar crystals, and the regions near the upper surface of the molten pool form equiaxial crystals and columnar dendritic structures deviating from the epitaxial growth direction, collectively referred to as "hybrid structures". Such a heterocrystal structure can seriously deteriorate the high-temperature properties of the single crystal superalloy, such as high-temperature creep and high-temperature fatigue properties. In addition, the formation of mixed crystals also introduces grain boundaries, thereby providing a thermal crack formation position and an extended path. When the repair area has a mixed crystal structure, the repair of the single crystal superalloy can be directly failed. Therefore, the inhibition of the formation of mixed crystals in the repair process of the single crystal superalloy is a key problem. Patent CN 104947175A discloses a method for preparing single crystal superalloy bulk material by 3D printing, in which the later layer is remelted to the previous layer of mixed crystal during deposition to improve the epitaxial growth of single crystal, but the control of thermal cracking between layers in the method still needs to be improved, the last layer of mixed crystal layer needs to be machined and removed, which results in material waste, and the deposition efficiency of single crystal in the method is relatively low, and the success rate of mixed crystal elimination is limited to a narrow process window. Patent CN 110055526A discloses an energy-constrained single crystal superalloy laser epitaxial growth method, which adopts a special tool to filter a gaussian light source to obtain more uniform energy distribution, thereby achieving a better effect of inhibiting mixed crystals, but the shape of the tool is relatively simple, and the adaptability to single crystal components with complex shapes is not good. In the usual case.
Disclosure of Invention
The invention aims at solving the problem of mixed crystals in the process of repairing single-crystal high-temperature alloy, and provides a method for eliminating the mixed crystals in the process of repairing the single-crystal high-temperature alloy by using a double-beam laser deposition-remelting composite technology.
The invention relates to a synchronous melting deposition-remelting elimination method of single crystal superalloy mixed crystal defects based on double-beam laser, which is carried out according to the following steps:
the method comprises the following steps: pretreating a single crystal high-temperature alloy sample, processing the single crystal high-temperature alloy, enabling the surface of the sample to be repaired to be parallel to a (001) crystal face, polishing and flattening the surface of the sample by No. 600 abrasive paper, and finally cleaning the sample by using acetone and then blowing the sample to be dried for later use;
step two: fixing a sample on a clamp, setting the defocusing amount of the front laser, and adjusting the positions of a powder feeding head and the front laser to enable a powder feeding point to be positioned in the area of a first beam of laser;
step three: preposed laser deposition process parameters:
setting the deposition power of the preposed laser at 500- +10mm, the defocusing amount at-10 to +10mm, the laser scanning speed at 0.005-0.02m/s, the grain diameter of the single crystal powder at 45-105 mu m and the powder feeding speed at 2-10 g/min;
step four: post laser remelting process parameters:
1) calculating the parameters of the single-layer mixed crystal region under the condition of the preposed laser process, and determining the width W of the mixed crystal regionSGHeight H from the hetero-crystalline regionSGA value of (d);
2) setting the spot diameter D of the postpositional laserb＝WSGThen calculating the power of the post laser, and requiring the power of the post laser to reach the remelting depth HRE＞HSGWherein H isRERepresenting the depth of laser remelting, HSGRepresenting the thickness of the mixed crystal layer, and controlling the distance between the two beams of laser within the range of 5-15 mm;
step five: after all the parameters are set, single crystal repair is carried out, and the whole repair process is carried out in an argon environment, wherein the oxygen content is lower than 50 ppm.
Further, in step two, the sample is fixed on a jig equipped with a cooling system.
Further, in step 1) of the fourth step, calculating parameters of the single-layer mixed crystal region under the condition of the pre-laser process is completed by the following method:
calculating different temperature gradients and solidification speeds in the molten pool in the single-layer deposition process according to process parameters by using finite element simulation software, then calculating the isometric crystal transition position of the columnar crystal by combining the criterion of columnar crystal-isometric crystal transition, and finally obtaining the H of the isometric crystal layerSG(ii) a The criterion formula of the columnar crystal-equiaxed crystal transformation is as follows:
Figure BDA0002574542330000021
wherein G is temperature gradient, V is solidification speed, phi is volume fraction of equiaxed crystal, and N is0To nucleate the number of particles, a and n are the physical parameters of the material.
Further, in step 2) of the fourth step, the power of the post laser is calculated by:
first, it is ensured that the remelting depth of the post laser is greater than the thickness of the heterocrystal layer (i.e., H)RE＞HSG) In order to calculate the corresponding remelting power, H is takenRE＝1.1HSG. Then calculating the remelting depth H through finite element simulation softwareRECorresponding laser remelting power (P)RE) I.e. the power of the post laser, wherein the scanning speed is the moving speed of the pre laser.
Furthermore, in the third step, the deposition power of the preposed laser is 600- + 900W, the defocusing amount is-8 to +8mm, the laser scanning speed is 0.008 to 0.02m/s, the grain size of the single crystal powder is 50 to 100 mu m, and the powder feeding speed is 3 to 8 g/min.
Further, in the third step, the deposition power of the preposed laser is set to be 700- +6mm, the defocusing amount is set to be-6 to +6mm, the laser scanning speed is 0.01 to 0.02m/s, the grain diameter of the single crystal powder is 60 to 80 mu m, and the powder feeding speed is set to be 3 to 7 g/min.
Further, in the third step, the deposition power of the preposed laser is set to be 500-800W, the defocusing amount is-5 to +5mm, the laser scanning speed is 0.015-0.02m/s, the grain diameter of the single crystal powder is 60-70 μm, and the powder feeding speed is 3-6 g/min.
Further, in the third step, the deposition power of the preposed laser is set to be 500- +3mm, the defocusing amount is set to be-3 to +3mm, the laser scanning speed is 0.015 to 0.02m/s, the grain diameter of the single crystal powder is 50 to 80 mu m, and the powder feeding speed is 5 to 7 g/min.
Further, in the third step, the deposition power of the preposed laser is set to be 500- +3mm, the defocusing amount is set to be-3 to +3mm, the laser scanning speed is 0.015 to 0.02m/s, the grain diameter of the single crystal powder is 50 to 80 mu m, and the powder feeding speed is 5 to 7 g/min.
Furthermore, in the third step, the deposition power of the preposed laser is set to be 500- + 900W, the defocusing amount is 0 to +2mm, the laser scanning speed is 0.01-0.02m/s, the grain diameter of the single crystal powder is 50-60 μm, and the powder feeding speed is 3-6 g/min.
Further, in the third step, the deposition power of the preposed laser is set to be 700- +1mm, the defocusing is 0 to +1mm, the laser scanning speed is 0.01 to 0.02m/s, the grain diameter of the single crystal powder is 70 to 100 mu m, and the powder feeding speed is 5 to 8 g/min.
The invention uses double-beam continuous laser arranged longitudinally along the laser scanning direction, the distance between two laser focuses is kept between 2mm and 15mm, and the specific position relation between the laser beam scanning direction and a single crystal sample is shown in figure 1. The powder is fed by a paraxial powder feeding mode, a preposed laser beam (a laser beam positioned at the forefront along the scanning direction) in the double-beam laser melts the powder and a single crystal substrate, a postposed laser beam (a laser beam positioned at the back along the scanning direction) directly acts on the surface of a deposition layer which is not completely solidified and is just deposited by the preposed laser, mixed crystals in a surface layer area or crystal nuclei in a melt are remelted directly by the postposed laser beam, and then the powder is re-solidified under a positive temperature gradient, so that the next layer is ensured to be deposited on the surface of the complete single crystal.
In order to realize the purpose of eliminating the formation of mixed crystals in the process of repairing the single crystal superalloy, the specific method of the invention comprises the following steps:
1. the method is characterized in that a single crystal high-temperature alloy sample needs to be pretreated, the surface of the sample to be repaired is vertical to the [001] crystal direction, the surface of the sample is polished to be flat by coarse abrasive paper, and the repaired surface is guaranteed to have certain roughness so as to reduce the reflectivity of the surface to laser.
2. Fixing the sample on a clamp provided with a cooling system, selecting a certain defocusing amount by the front laser, and adjusting the positions of the powder feeding head and the front laser to enable the powder feeding point to be positioned in the area of the first laser beam.
3. And determining parameters of the single-layer mixed crystal area under the condition of the preposed laser process, as shown in figure 2. Determining the width W of the hetero-crystalline regionSGHeight H from the hetero-crystalline regionSGThe value of (c).
4. Setting the spot diameter D of the postpositional laserb＝WSGThe distance between two laser beams is controlled within 5-15mm, and the distance is measured based on the temperature of the interface position between the bottom of the mixed crystal region and the single crystal regionCalculating the power of the post laser, and requiring the power of the post laser to reach the remelting depth HRE＞HSG。
5. And after all the parameters are set, carrying out a single crystal repairing experiment.
The design principle of the invention is as follows:
on the basis of forming epitaxial growth tissue under the condition of utilizing laser to produce directional high-temperature gradient, the invention adds extra laser beam to completely remelt the impurity crystal zone on the upper portion of the deposition layer, and then continuously forms nearly complete epitaxial growth single crystal tissue under the condition of high-temperature gradient. Generally, the transformation of columnar crystals into equiaxed crystals or mixed crystals due to unfused powder at the surface occurs after each layer is deposited due to a significant decrease in temperature gradient in the area near the surface of the deposited layer. For the above-mentioned mixed crystals, if the laser surface remelting treatment is carried out immediately, the mixed crystals can be effectively and completely remelted, and finally the remelted mixed crystals are solidified to form an epitaxial growth single crystal structure.
The method has obvious difference from the common double light beams: the two laser beams of the method do not act in one molten pool at the same time, the preposed laser and the postpositional laser form two independent molten pools, and the function of the postpositional laser for forming the molten pool is used for remelting mixed crystals on the upper part under the preposed laser parameters.
The method has the core that the parameters of the subsequent laser are determined, and the upper mixed crystal can be completely remelted: firstly, parameters of a single-layer mixed crystal region under the condition of the pre-laser process are obtained by using a simulation method or an experimental method, as shown in fig. 2. Determining the width W of the hetero-crystalline regionSGHeight H from the hetero-crystalline regionSGThe value of (c). Spot diameter D of fixed post laserb＝WSGThe scanning speed of the back laser is the same as that of the front laser, and the back laser and the front laser are remelted according to the energy input and the laser remelting depth HREThe power of the post laser is obtained, and the remelting depth H caused by the combined action of the power of the post laser and the temperature of the mixed crystal area is requiredRE＞HSGTo completely remelt the heterocrystal region and subsequently form a monolayer of the fully single-crystal structure.
The invention has the beneficial effects that:
1. the invention introduces the tandem type double laser beams, which can ensure that mixed crystals formed after deposition of each layer are effectively remelted under the condition of high enough temperature gradient and then solidified into a single crystal structure, thereby effectively enlarging the process window.
2. The method can effectively reduce the residual stress of each layer of deposition layer, further reduce the sensitivity of thermal cracks in the solidification process and simultaneously reduce the recrystallization tendency of the subsequent heat treatment link;
3. after laser remelting is combined, the surface roughness of a repair area is obviously reduced, and the size and the shape of a deposition area are stable.
4. Compared with the common repairing method, the method can obviously improve the success rate and the repairing efficiency of the repairing of the single crystal.
5. The method for eliminating the mixed crystals by laser remelting after laser deposition of a layer can cause the problem of uneven structure in the deposited layer, and especially when the component is in a complicated shape and has a long path, the problem of uneven structure is more serious; the method utilizes a synchronous laser deposition and remelting method, and particularly when the shape of a component is complicated and the path is long, a single crystal structure with uniform tissue can be obtained in each layer, and finally the overall uniform tissue is obtained.
6. The method has great potential in repair of the single crystal blade and even direct additive manufacturing of the single crystal blade in the future.
Drawings
FIG. 1 is a schematic diagram of a double-beam laser deposition-remelting composite technology for repairing single crystals;
FIG. 2 is a schematic diagram of a mixed crystal region at the upper part of a repair region;
FIG. 3 is a topographical view of a conventional single-beam laser deposition repaired tissue of example 2;
FIG. 4 is a graph of the morphology of the double-beam laser deposition-remelting composite repaired tissue of example 1.
Detailed Description
It will be understood by those of ordinary skill in the art that the foregoing embodiments are specific examples for carrying out the invention, and that various changes in form and details may be made therein without departing from the spirit and scope of the invention in practice.
To make the objects, aspects and advantages of the embodiments of the present invention more apparent, the following detailed description clearly illustrates the spirit of the disclosure, and any person skilled in the art, after understanding the embodiments of the disclosure, may make changes and modifications to the technology taught by the disclosure without departing from the spirit and scope of the disclosure.
The exemplary embodiments of the present invention and the description thereof are provided to explain the present invention and not to limit the present invention.
The specific test scheme of the conventional single-beam laser deposition repair method and the method of the invention is as follows:
example 1
The method is adopted to carry out a double-beam laser deposition-remelting composite repair test:
the method comprises the following steps: pretreating a single crystal high-temperature alloy sample, and processing the single crystal high-temperature alloy into a cylinder with the diameter of 15mm and the height of 10 mm; the bottom surface of the cylinder is the surface of a sample to be repaired and is vertical to the [001] crystal direction, the surface of the sample is polished and leveled by No. 600 abrasive paper, and finally, the sample is cleaned by acetone and then is blown dry for later use;
step two: fixing the sample on a clamp provided with a cooling system, adopting paraxial powder feeding, and simultaneously adjusting the positions of a powder feeding head and a first laser beam to enable a powder feeding point to be positioned in the area of the first laser beam.
Step three: preposed laser deposition process parameters:
setting the deposition power of the preposed laser to be 800W, the defocusing amount to be +5mm, the laser scanning speed to be 0.01m/s, the grain diameter of the single crystal powder to be 45-105 mu m and the powder feeding speed to be 5 g/min.
Step four: post laser remelting process parameters:
1. calculating the size parameter of the impurity crystal region: width W of hetero-crystal regionSG1.2 mm; height H of hetero-crystalline regionSG＝100μm。
2. Setting the spot diameter D of the postpositional laserb＝WSGThen, the power P of the post laser is calculated to be 240W, which satisfies the power of the post laserDepth of remelting HRE＞HSG. In addition, the distance between the two laser beams is controlled at 10 mm.
Step five: and after all the parameters are set, carrying out a single crystal repairing experiment. The whole repairing process is ensured to be carried out in an argon environment, and the oxygen content is lower than 50 ppm. And obtaining a repair sample after laser scanning deposition and 10-layer remelting.
The metallographic photograph of the structure of the repaired area in this example is shown in FIG. 4.
In the step 1) of the fourth step, the calculation of the parameters of the single-layer mixed crystal area under the condition of the preposed laser process is completed in the following way:
calculating different temperature gradients and solidification speeds in the molten pool in the single-layer deposition process according to process parameters by using finite element simulation software, then calculating the isometric crystal transition position of the columnar crystal by combining the criterion of columnar crystal-isometric crystal transition, and finally obtaining the H of the isometric crystal layerSG(ii) a The columnar crystal-isometric crystal transformation formula is as follows:
Figure BDA0002574542330000061
wherein G is temperature gradient, V is solidification speed, phi is volume fraction of equiaxed crystal, and N is0To nucleate the number of particles, a and n are the physical parameters of the material.
In step 2) of the fourth step, the calculation of the power of the post-laser is completed by the following steps:
first, it is ensured that the remelting depth of the post laser is greater than the thickness of the heterocrystal layer (i.e., H)RE＞HSG) In order to calculate the corresponding remelting power, H is takenRE＝1.1HSG. Then calculating the remelting depth H through finite element simulation softwareRECorresponding laser remelting power (P)RE) I.e. the power of the post laser, wherein the scanning speed is the moving speed of the pre laser.
Example 2
A conventional single-beam laser deposition repair test is adopted:
the method comprises the following steps: pretreating a single crystal high-temperature alloy sample, and processing the single crystal high-temperature alloy into a cylinder with the diameter of 15mm and the height of 10 mm; the bottom surface of the cylinder is the surface of a sample to be repaired and is vertical to the [001] crystal direction, the surface of the sample is polished and leveled by No. 600 abrasive paper, and finally, the sample is cleaned by acetone and then is blown dry for later use;
step two: fixing the sample on a clamp provided with a cooling system, adopting paraxial powder feeding, and simultaneously adjusting the positions of a powder feeding head and a first laser beam to enable a powder feeding point to be positioned in the area of the first laser beam.
Step three: laser deposition process parameters:
the laser deposition power is 800W, the defocusing amount is +5mm, the laser scanning speed is 0.01m/s, the grain diameter of the single crystal powder is 45-105 mu m, and the powder feeding speed is 5 g/min.
Step four: and after all the parameters are set, carrying out a single crystal repairing experiment. The whole repairing process is ensured to be carried out in an argon environment, and the oxygen content is lower than 50 ppm. After 10 layers of laser scanning deposition, a repair sample is obtained. The photograph of the repair area of this example is shown in FIG. 3.
Comparing fig. 3 and fig. 4, it can be found that the tissue of the single crystal repair area repaired by the conventional single-beam laser deposition has more mixed crystals, and a small amount of incompletely melted powder remains on the surface. Compared with the conventional single-beam laser deposition repair, the repair area after the double-beam laser deposition-remelting composite repair is a complete single-crystal tissue, and meanwhile, incompletely-melted powder residues do not exist on the surface. In addition, the height of the repair area is also obviously higher than that of the conventional single-laser control embodiment, so that the repair efficiency is obviously improved.

Claims (10)

1. A synchronous melting deposition-remelting elimination method of single crystal superalloy mixed crystal defects based on double-beam laser is characterized by comprising the following steps:
the method comprises the following steps: pretreating a single crystal high-temperature alloy sample, processing the single crystal high-temperature alloy, enabling the surface of the sample to be repaired to be parallel to a (001) crystal face, polishing and flattening the surface of the sample by No. 600 abrasive paper, and finally cleaning the sample by using acetone and then blowing the sample to be dried for later use;
step two: fixing a sample on a clamp, setting the defocusing amount of the front laser, and adjusting the positions of a powder feeding head and the front laser to enable a powder feeding point to be positioned in the area of a first beam of laser;
step three: preposed laser deposition process parameters:
setting the deposition power of the preposed laser at 500- +10mm, the defocusing amount at-10 to +10mm, the laser scanning speed at 0.005-0.02m/s, the grain diameter of the single crystal powder at 45-105 mu m and the powder feeding speed at 2-10 g/min;
step four: post laser remelting process parameters:
1) calculating the parameters of the single-layer mixed crystal region under the condition of the preposed laser process, and determining the width W of the mixed crystal regionSGHeight H from the hetero-crystalline regionSGA value of (d);
2) setting the spot diameter D of the postpositional laserb＝WSGThen calculating the power of the post laser, and requiring the power of the post laser to reach the remelting depth HRE＞HSGWherein H isRERepresenting the depth of laser remelting, HSGRepresenting the thickness of the mixed crystal layer, and controlling the distance between the two beams of laser within the range of 5-15 mm;
step five: after all the parameters are set, single crystal repair is carried out, and the whole repair process is carried out in an argon environment, wherein the oxygen content is lower than 50 ppm.
2. The method for synchronously melting, depositing and remelting elimination of single crystal superalloy mixed crystal defects based on the dual-beam laser as claimed in claim 1, wherein in the second step, the sample is fixed on a fixture with a cooling system.
3. The method for synchronously melting, depositing and remelting elimination of single-crystal superalloy mixed crystal defects based on double-beam laser as claimed in claim 1, wherein in step 1) of the fourth step, the parameters of the single-layer mixed crystal region under the preposed laser process condition are calculated by:
calculating different temperature gradients and solidification speeds in the molten pool in the single-layer deposition process according to process parameters by using finite element simulation software, and then calculating by combining the criterion of columnar crystal-isometric crystal transformationThe equiaxed crystal transformation position of the columnar crystal is obtained, and finally the H of the equiaxed crystal layer is obtainedSG(ii) a The criterion formula of the columnar crystal-equiaxed crystal transformation is as follows:
Figure FDA0002574542320000011
wherein G is temperature gradient, V is solidification speed, phi is volume fraction of equiaxed crystal, and N is0To nucleate the number of particles, a and n are the physical parameters of the material.
4. The method for synchronously melting, depositing and remelting the single crystal superalloy mixed crystal defects based on the double-beam laser as claimed in claim 1, wherein in step 2) of the fourth step, the power of the post laser is calculated by:
first, it is ensured that the remelting depth of the post laser is greater than the thickness of the heterocrystal layer (i.e., H)RE＞HSG) In order to calculate the corresponding remelting power, H is takenRE＝1.1HSG. Then calculating the remelting depth H through finite element simulation softwareRECorresponding laser remelting power (P)RE) I.e. the power of the post laser, wherein the scanning speed is the moving speed of the pre laser.
5. The method for synchronously melting, depositing and remelting elimination of mixed crystal defects of single-crystal high-temperature alloy based on double-beam laser as claimed in claim 1, wherein in the third step, the deposition power of the preposed laser is set to be 600- + 900W, the defocusing amount is-8- +8mm, the laser scanning speed is 0.008-0.02m/s, the grain size of single-crystal powder is 50-100 μm, and the powder feeding speed is 3-8 g/min.
6. The method for synchronously melting, depositing and remelting elimination of mixed crystal defects of single-crystal high-temperature alloy based on double-beam laser as claimed in claim 1, wherein in the third step, the deposition power of the preposed laser is set to be 700- + 800W, the defocusing amount is-6- +6mm, the laser scanning speed is 0.01-0.02m/s, the grain size of single-crystal powder is 60-80 μm, and the powder feeding speed is 3-7 g/min.
7. The method for synchronously melting, depositing and remelting elimination of mixed crystal defects of single-crystal high-temperature alloy based on double-beam laser as claimed in claim 1, wherein in the third step, the deposition power of the preposed laser is set to be 500- +5mm, the defocusing amount is set to be-5- +5mm, the laser scanning speed is set to be 0.015-0.02m/s, the grain diameter of single-crystal powder is set to be 60-70 μm, and the powder feeding speed is set to be 3-6 g/min.
8. The method as claimed in claim 1, wherein the method comprises the third step of setting the deposition power of the pre-laser at 500- +3mm, the defocusing amount at-3- +3mm, the laser scanning speed at 0.015-0.02m/s, the grain size of the single crystal powder at 50-80 μm, and the powder feeding rate at 5-7 g/min.
9. The method for synchronously melting, depositing and remelting elimination of mixed crystal defects of single-crystal high-temperature alloy based on double-beam laser as claimed in claim 1, wherein in the third step, the deposition power of the preposed laser is set to be 500- +2mm, the defocusing amount is set to be 0.01-0.02m/s, the particle size of the single-crystal powder is 50-60 μm, and the powder feeding rate is set to be 3-6 g/min.
10. The method for synchronously melting, depositing and remelting elimination of mixed crystal defects of single-crystal high-temperature alloy based on double-beam laser as claimed in claim 1, wherein in the third step, the deposition power of the preposed laser is set to be 700- +1mm, the defocusing is set to be 0.01-0.02m/s, the particle size of the single-crystal powder is 70-100 μm, and the powder feeding rate is set to be 5-8 g/min.
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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113684426A (en) * 2021-08-31 2021-11-23 北京煜鼎增材制造研究院有限公司 High-tungsten steel and preparation method thereof
CN114535618A (en) * 2021-12-07 2022-05-27 南京钛陶智能系统有限责任公司 Three-dimensional printing system
WO2022214630A1 (en) * 2021-04-10 2022-10-13 Dadbakhsh Sasan System and method for forming single crystal components using additive manufacturing tooling

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101126143A (en) * 2006-08-16 2008-02-20 中国科学院金属研究所 Directional freezing styloid or single-crystal nickel-base high-temperature alloy repairing or coating method
CN103160825A (en) * 2013-03-18 2013-06-19 张翀昊 Method for improving metal 3D (three-dimensional) printing compactness by utilizing synchronous double-beam laser
CN104985327A (en) * 2015-07-27 2015-10-21 哈尔滨工业大学 Bifocus laser and InFocus arc hybrid welding method
CN105834427A (en) * 2016-05-27 2016-08-10 西安交通大学 Device and method for assisting in carrying out temperature control 3D printing on directional crystallization part by means of multiple laser beams
EP3587006A1 (en) * 2018-06-27 2020-01-01 Siemens Aktiengesellschaft 3d-printing method and manufacturing device

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101126143A (en) * 2006-08-16 2008-02-20 中国科学院金属研究所 Directional freezing styloid or single-crystal nickel-base high-temperature alloy repairing or coating method
CN103160825A (en) * 2013-03-18 2013-06-19 张翀昊 Method for improving metal 3D (three-dimensional) printing compactness by utilizing synchronous double-beam laser
CN104985327A (en) * 2015-07-27 2015-10-21 哈尔滨工业大学 Bifocus laser and InFocus arc hybrid welding method
CN105834427A (en) * 2016-05-27 2016-08-10 西安交通大学 Device and method for assisting in carrying out temperature control 3D printing on directional crystallization part by means of multiple laser beams
EP3587006A1 (en) * 2018-06-27 2020-01-01 Siemens Aktiengesellschaft 3d-printing method and manufacturing device

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
李涤尘等编: "《高温透平叶片增材制造技术》", 31 October 2016, 西安交通大学出版社 *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2022214630A1 (en) * 2021-04-10 2022-10-13 Dadbakhsh Sasan System and method for forming single crystal components using additive manufacturing tooling
CN113684426A (en) * 2021-08-31 2021-11-23 北京煜鼎增材制造研究院有限公司 High-tungsten steel and preparation method thereof
CN114535618A (en) * 2021-12-07 2022-05-27 南京钛陶智能系统有限责任公司 Three-dimensional printing system
CN114535618B (en) * 2021-12-07 2024-03-19 南京钛陶智能系统有限责任公司 Three-dimensional printing system

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