阅读说明：本技术 快速修复服役末期镍基高温合金涡轮盘的方法 (Method for rapidly repairing nickel-based superalloy turbine disc at last service stage ) 是由 张新房 张海荷 秦书洋 于 2019-11-29 设计创作，主要内容包括：本发明涉及先进航空发动机涡轮盘延寿技术领域,提供了一种快速修复服役末期镍基高温合金涡轮盘的方法,对服役末期的性能恶化的高温合金涡轮盘在一定温度下进行脉冲电流处理,所述方法显著改善合金涡轮盘的显微组织及力学性能；所述脉冲处理的参数范围：频率10Hz～30000Hz,脉宽10μs～500μs,电流10A～5000A,作用时间1min～10h。本发明可在较低温度下对服役末期涡轮盘进行处理,降低材料中脆性拓扑密堆相的数量密度,最大程度地恢复老化高温合金涡轮盘的力学性能；该方法处理时间短、温度低,可大大降低能源消耗,符合当前工业绿色发展规划的要求,为高温合金涡轮盘的延寿提供了新方法,具有广阔应用前景。(The invention relates to the technical field of the service life prolonging of advanced aeroengine turbine disks, and provides a method for quickly repairing a nickel-based high-temperature alloy turbine disk at the end of service, wherein the high-temperature alloy turbine disk with deteriorated performance at the end of service is subjected to pulse current treatment at a certain temperature, and the method obviously improves the microstructure and mechanical property of the alloy turbine disk; parameter ranges of the pulse processing: the frequency is 10 Hz-30000 Hz, the pulse width is 10 mus-500 mus, the current is 10A-5000A, and the acting time is 1 min-10 h. The invention can process the turbine disc at the end of service at lower temperature, reduce the number density of brittle topological close-packed phases in the material and recover the mechanical property of the aged high-temperature alloy turbine disc to the maximum extent; the method has short treatment time and low temperature, can greatly reduce energy consumption, meets the requirement of the current industrial green development plan, provides a new method for prolonging the service life of the high-temperature alloy turbine disc, and has wide application prospect.)

1. A method for rapidly repairing a nickel-based superalloy turbine disc at the end of service is characterized in that the method carries out pulse current processing on the superalloy turbine disc with deteriorated performance at the end of service at a certain temperature, and parameters of the pulse processing comprise frequency, pulse width, current magnitude and action time; the method can obviously improve the microstructure and the mechanical property of the alloy turbine disk.

2. The method for rapidly repairing an end-of-service nickel-base superalloy turbine disk of claim 1, wherein the pulse process has a parameter range of: the frequency is 10 Hz-30000 Hz, the pulse width is 10 mus-500 mus, the current is 10A-5000A, and the acting time is 1 min-10 h.

3. The method for rapidly repairing an end-of-service nickel-base superalloy turbine disk as in claim 1 or 2, wherein the method comprises the steps of:

s1, determining the performance deterioration degree of the nickel-based superalloy turbine disc, and determining parameters of pulse current processing according to the performance deterioration degree;

and S2, connecting the nickel-based superalloy turbine disc to a pulse power supply through a pure copper wire, and performing pulse current processing according to the parameters determined in the step S1.

4. The method for rapidly repairing an end-of-service nickel-base superalloy turbine disk as in claim 3, wherein in step S1, the degree of performance degradation of the nickel-base superalloy turbine disk is measured by an equivalent thermal aging process in a simulation; the equivalent thermal aging treatment parameters comprise the material, the thermal aging temperature and the thermal aging of the alloy turbine disc; the corresponding relation between the performance deterioration degree of the nickel-based superalloy turbine disc and the equivalent thermal aging treatment parameters is determined through experience or experiments.

5. The method of rapidly repairing an end-of-service nickel-base superalloy turbine disk of claim 4, wherein the corresponding pulse current processing parameter is determined based on the equivalent thermal aging processing parameter.

6. The method for rapidly repairing an end-of-service nickel-base superalloy turbine disk of claim 5, wherein the equivalent heat aging process parameter is: the FGH4096 high-temperature alloy turbine disk is aged for 700h under the condition of 850 ℃, and the corresponding pulse current processing parameters are as follows: the frequency is 40-30000Hz, the pulse width is 20-75 mus, the current is 150-.

7. The method for rapid repair of end-of-service nickel-base superalloy turbine disks according to any of claims 1 to 2, 4 to 6, wherein the pulsed current treatment is performed at room temperature.

8. The method of rapidly repairing an end-of-service nickel-base superalloy turbine disk of claim 1, wherein the improving the microstructure of the alloy turbine disk comprises reducing a number density of brittle topological close-packed phases in the material; the mechanical properties of the alloy turbine disk are improved, including the tensile strength and the elongation percentage after fracture of the alloy turbine disk.

Technical Field

The invention relates to the technical field of life prolonging of advanced aeroengine turbine disks, in particular to a method for quickly repairing a nickel-based high-temperature alloy turbine disk at the end of service.

Background

The high-temperature alloy is taken as the most important and promising temperature bearing material of the aeroengine at present, has good oxidation resistance, corrosion resistance, excellent tensile property, durability, fatigue property and long-term structure stability, is widely applied to the modern aerospace technology, and shows strong vitality in the field of the advanced aeroengine. The service life of the turbine disk is always the focus of attention in the industry, and the service life of the advanced aircraft engine is generally about 5000 h. The high-temperature alloy turbine disk can generate a large amount of topological close-packed phases (TCP phases) in materials under long-term high-temperature and high-stress conditions, and the high-temperature mechanical properties of the turbine disk are seriously damaged, particularly the high-temperature durable life. The presence of the TCP phase is one of the primary reasons limiting the service time of superalloy turbine disks. The cost of a single engine is as high as thousands of millions or even billions of RMB, and if the service life of the aged turbine disc can be prolonged in an on-line mode by some means, huge economic benefits can be generated in the aerospace field.

At present, laser repair is widely applied to repair of nickel-based high-temperature alloy, and the method adopts a rapid forming repair technology for damaged metal parts by taking laser as a high-energy heat source. According to the technology, the laser deposited liquid metal is high in cooling rate, the repaired tissue is uniform and fine, and the density is high, but a large amount of brittle TCP phases can be formed in the later solidification stage of the liquid metal in the repairing process to seriously affect the mechanical property of the material. The patent (CN109182935B) discloses a method for eliminating brittle phases in laser-repaired nickel-based superalloy, namely, the laser-repaired nickel-based superalloy is subjected to delta aging treatment at 850-970 ℃/5-12 h to complete elimination of Laves brittle phases; and then carrying out delta solution treatment at the temperature of 1015-1035 ℃/3-10 h to eliminate the delta phase precipitated in the previous step. In addition, patent (CN 102912269a) discloses a heat treatment method for recovering the properties of an aged solid solution strengthened nickel-based superalloy, which is to perform solid solution treatment on an aged member at 1000-1300 ℃, dissolve back and control excessive precipitated phases, and reduce the continuous precipitation of the precipitated phases at grain boundaries and dislocations, thereby improving the plasticity and high-temperature mechanical properties of the material. The two high-temperature alloys for improving the mechanical property are complex to operate, long in period and high in working condition temperature, and do not accord with the requirements of the current industrial green development planning.

The high-quantity-density TCP phase precipitated in the service process under the conditions of high temperature and high stress is a key factor for limiting the service time of the high-temperature alloy turbine disk, and the harm of the precipitation of the TCP phase to the mechanical property of the material is irreversible. At present, no reasonable solution is provided for the problem in the industry, and no effective means is provided for dissolving the brittle topological dense packing phase existing in the aged high-temperature alloy so as to achieve the purposes of restoring the performance and prolonging the service life of the high-temperature service component.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a method for quickly repairing a nickel-based superalloy turbine disc at the end of service, which can quickly reduce the number density of brittle topological close-packed phases and recover the mechanical property of an aged superalloy turbine disc through pulse current treatment.

The principle of the invention is as follows:

in the traditional heat treatment process, the TCP phase is dissolved only by depending on the increase of the atomic diffusion rate under the high-temperature condition, and the process for achieving the aging performance recovery by a simple thermal field needs extremely high temperature to carry out long-time treatment on the aged turbine disc. The invention discovers that: the pulse current is used as a special treatment means with instantaneous high energy, and can quickly dissolve brittle TCP phases in an aged high-temperature alloy turbine disc and reduce the number density of the brittle TCP phases, so that the aim of recovering the mechanical property of the material is fulfilled; more importantly, the pulse current treatment promotes the dissolution of the TCP phase by mainly relying on the electrochemical property difference between the TCP phase and the strengthening phase and the matrix, so that the aim of recovering the mechanical property of the aged turbine disc is fulfilled, which is the most essential difference between the pulse current treatment and the simple heat treatment.

The pulse current treatment of the invention has the advantages that the traditional process is difficult to compare favorably, and the specific expression is that the required working condition temperature is low, the time is short, the high-temperature alloy turbine disk with deteriorated performance at the end of service can be directly treated in situ by an external power supply, and the operation is simple. According to the invention, the number density of brittle topological close-packed phases is rapidly reduced and the mechanical property is recovered by accurately controlling the pulse current processing parameters, and the service time of the high-temperature alloy turbine disk is prolonged.

The invention adopts the following technical scheme:

a method for rapidly repairing a nickel-based superalloy turbine disc at the end of service is provided, the method carries out pulse current processing on the superalloy turbine disc with deteriorated performance at the end of service at a certain temperature, and parameters of the pulse processing comprise frequency, pulse width, current magnitude and action time; the method can obviously improve the microstructure and the mechanical property of the alloy turbine disk.

Further, the parameter range of the pulse processing is as follows: the frequency is 10 Hz-30000 Hz, the pulse width is 10 mus-500 mus, the current is 10A-5000A, and the acting time is 1 min-10 h.

Further, the method specifically comprises the steps of:

s1, determining the performance deterioration degree of the nickel-based superalloy turbine disc, and determining parameters of pulse current processing according to the performance deterioration degree;

and S2, connecting the nickel-based superalloy turbine disc to a pulse power supply through a pure copper wire, and performing pulse current processing according to the parameters determined in the step S1.

Further, in step S1, the performance deterioration degree of the nickel-based superalloy turbine disk is measured by an equivalent thermal aging process; the equivalent thermal aging treatment parameters comprise the material, the thermal aging temperature and the thermal aging of the alloy turbine disc; the corresponding relation between the performance deterioration degree of the nickel-based superalloy turbine disc and the equivalent thermal aging treatment parameters is determined through experience or experiments.

Further, determining corresponding pulse current processing parameters according to the equivalent thermal aging processing parameters. The corresponding relation between the equivalent thermal aging processing parameters and the pulse current processing parameters can be determined through tests to form a database, so that the application is convenient.

Further, the equivalent thermal aging treatment parameters are as follows: the FGH4096 high-temperature alloy turbine disk is aged for 700h under the condition of 850 ℃, and the corresponding pulse current processing parameters are as follows: the frequency is 40-30000Hz, the pulse width is 20-75 mus, the current is 150-.

Further, the pulsed current treatment is performed at room temperature.

Further, the microstructure of the alloy turbine disk is improved, and the number density of brittle topological close packing phases in the material is reduced; the mechanical properties of the alloy turbine disk are improved, including the tensile strength and the elongation percentage after fracture of the alloy turbine disk are improved,

the invention has the beneficial effects that: compared with the existing method for recovering the mechanical property of the aged high-temperature alloy turbine disc by utilizing high-temperature and long-time heat treatment, the method can be used for treating the turbine disc at the last service stage at a lower temperature, greatly reducing the number density of brittle topological close-packed phases in the material and recovering the mechanical property of the aged high-temperature alloy turbine disc to the maximum extent; the invention does not need additional heat source assistance, needs short time, can greatly reduce energy consumption, meets the requirement of the current industrial green development planning, and has wide application prospect.

Drawings

FIG. 1 is a metallographic photograph showing the distribution of brittle topological dense packing phases in a superalloy turbine disk selected for use in the aged state of example 1.

FIG. 2 is a metallographic photograph showing the distribution of brittle topological close-packed phases remaining in the superalloy turbine disk after treatment with the pulsed current of example 2.

FIG. 3 is a graph comparing the tensile properties of the materials of example 3 after aging and pulse treatments.

Detailed Description

Specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that technical features or combinations of technical features described in the following embodiments should not be considered as being isolated, and they may be combined with each other to achieve better technical effects. In the drawings of the embodiments described below, the same reference numerals appearing in the respective drawings denote the same features or components, and may be applied to different embodiments.

The high-temperature alloy turbine disc can reach the end of service only after being in service for at least 5000 hours under the real working condition, and a large amount of brittle topological close-packed phases are generated.

In view of the size limitation of a muffle furnace used for aging treatment, the total amount of samples and the difficulty in obtaining a performance-deteriorated turbine disk under the real service condition, the embodiment of the invention performs laboratory aging treatment and pulse current treatment tests on small-size turbine disk materials. In the pulse current processing process, for the turbine disks with different sizes, the current density in the processing process is constant only by adjusting the current according to the sizes of the turbine disks, and the same processing effect as that of the small-size turbine disks can be achieved (proved by tests).

In the embodiment of the invention, the performance deterioration degree of the nickel-based superalloy turbine disk is subjected to equivalent aging treatment: the high-temperature alloy turbine disk is subjected to simulated aging treatment in a thermal aging mode, and the high-temperature alloy turbine disk with high-density topological close-packed phase and performance deterioration is obtained (a metallographic photograph of brittle topological close-packed phase distribution is shown in figure 1). The material is taken as a research object, and the quantity and density of topological close-packed phases in the high-temperature alloy turbine disc with deteriorated performance are quickly reduced and the tensile mechanical property of the material is improved by controlling pulse current parameters (the frequency is 10 Hz-30000 Hz, the pulse width is 10 mus-500 mus, the current is 10A-5000A, and the acting time is 1 min-10 h), so that the aim of recovering the mechanical property of the high-temperature alloy turbine disc at the end of service is fulfilled.

In the following examples, the heat-treated FGH4096 was used as a test raw material, and heat aging treatment was carried out at 850 ℃ for 700 hours to obtain a high-temperature alloy turbine disk material with deteriorated properties.