阅读说明：本技术 定量评价真空度和氧化产物对高温合金性能影响的方法 (Method for quantitatively evaluating influence of vacuum degree and oxidation products on performance of high-temperature alloy ) 是由 郑亮 肖程波 张国庆 于 2020-05-09 设计创作，主要内容包括：本发明定量评价真空度和氧化产物对高温合金性能影响的方法,属于高温合金领域；通过熔炼时控制分级真空度、顺序凝固聚集氧化产物并配合测试对应状态的综合力学性能的方法,定量评价真空度、氧化产物及其对镍基高温合金力学性能影响,同时还可以确定合金中痕量氧化产物类型和含量,为制备工艺参数容限的确定提供依据,为高纯净度高温合金的制备、提高镍基高温合金制件的合格率和降低成本提供技术支撑和保障。本发明克服了解决了以往技术仅考虑真空度、凝固后试样的平均气体含量(包括氧含量)和合金力学性能几重因素造成的平均气体含量与力学性能无法直接挂钩等问题。(The invention relates to a method for quantitatively evaluating the influence of vacuum degree and oxidation products on the performance of a high-temperature alloy, belonging to the field of high-temperature alloys; by controlling the graded vacuum degree and sequentially solidifying and aggregating the oxidation products during smelting and matching with a method for testing the comprehensive mechanical property of the corresponding state, the vacuum degree, the oxidation products and the influence of the oxidation products on the mechanical property of the nickel-based superalloy are quantitatively evaluated, meanwhile, the type and the content of the trace oxidation products in the alloy can be determined, a basis is provided for determining the tolerance of preparation process parameters, and technical support and guarantee are provided for preparing the high-purity superalloy, improving the qualification rate of nickel-based superalloy workpieces and reducing the cost. The invention solves the problem that the average gas content and the mechanical property can not be directly hooked due to the fact that the prior art only considers several factors of the vacuum degree, the average gas content (including the oxygen content) of a solidified sample and the mechanical property of the alloy.)

1. The method for quantitatively evaluating the influence of the vacuum degree and the oxidation product on the performance of the high-temperature alloy is characterized by comprising the following steps of: preparing high-temperature alloy samples solidified under different vacuum conditions by controlling the graded vacuum degree and the holding time during smelting, measuring the gas content and the mechanical property of the samples under different vacuum conditions, remelting the high-temperature alloy samples under different vacuum conditions again under high vacuum, adopting sequential solidification to aggregate oxidation products, identifying the types of the oxidation products, determining the forms, the components and the content of the oxidation products under different vacuum conditions, determining the existence form of oxygen, and determining and evaluating the quantitative relation of the influence of the vacuum degree, the gas content, the forms, the types and the content of the oxidation products on the performance of the high-temperature alloy.

2. The method for quantitatively evaluating the influence of the vacuum degree and the oxidation products on the mechanical property of the high-temperature alloy as claimed in claim 1, wherein the method comprises the following steps: the grading vacuum degree refers to different vacuum degree grades of high, medium and low, the highest vacuum degree is the ultimate vacuum degree of the equipment, and the lowest vacuum degree can reach the atmospheric environment.

3. The method for quantitatively evaluating the influence of the vacuum degree and the oxidation products on the mechanical property of the high-temperature alloy as claimed in claim 1, wherein the method comprises the following steps: the high-temperature alloy sample is obtained by remelting a cut high-temperature alloy master alloy ingot in a vacuum induction melting furnace, and placing the melt into a furnace 10 after melting and cleaning^-2Pa-10³Respectively cooling and solidifying under the conditions of different vacuum degrees of Pa and 1-100min of holding time.

4. The method for quantitatively evaluating the influence of the vacuum degree and the oxidation products on the mechanical property of the high-temperature alloy as claimed in claim 3, wherein the method comprises the following steps: the high-temperature alloy master alloy ingot is prepared by vacuum induction melting.

5. The method for quantitatively evaluating the influence of the vacuum degree and the oxidation products on the mechanical property of the high-temperature alloy according to claim 1, wherein the method comprises the following steps: the sequentially solidified and aggregated oxidation product is prepared by remelting and solidifying high-temperature alloy samples under different vacuum conditions at 10 DEG C^-3Pa-10^-4Remelting again in a Pa high vacuum environment, and sequentially cooling to realize sequential solidification process from bottom to top of solid, solid-liquid and liquid respectively, so as to obtain trace (ppm) level in alloyThe oxidation products float and gather in the last solidification area of the upper surface in the sequential solidification process.

6. The method for quantitatively evaluating the influence of the vacuum degree and the oxidation products on the mechanical property of the high-temperature alloy according to claim 1, wherein the method comprises the following steps: the identification of the oxidation product species is carried out by using synchrotron radiation X-ray diffraction identification.

7. The method for quantitatively evaluating the influence of the vacuum degree and the oxidation products on the mechanical property of the high-temperature alloy according to claim 1, wherein the method comprises the following steps: the shape, the components and the content of the oxidation product under different vacuum conditions are determined by a scanning electron microscope and an energy spectrum, and the content of the oxidation product is determined by adopting a quantitative metallographic phase or an extraction separation method.

8. The method for quantitatively evaluating the influence of the vacuum degree and the oxidation products on the mechanical property of the high-temperature alloy according to claim 1, wherein the method comprises the following steps: the quantitative relationship is at 10^-2Pa～10³Pa vacuum degree, 1-100min holding time, ppm gas content, oxidation product amount and corresponding quantitative corresponding relation of high temperature alloy performance.

9. The method for quantitatively evaluating the influence of the vacuum degree and the oxidation products on the mechanical property of the high-temperature alloy according to claim 1, wherein the method comprises the following steps: before remelting again, the high-temperature alloy samples under different vacuum conditions need to be processed into gas test samples and mechanical property test bars, and gas content and mechanical property tests are respectively carried out.

10. The method for quantitatively evaluating the influence of the vacuum degree and the oxidation products on the mechanical property of the high-temperature alloy according to claim 9, wherein the method comprises the following steps: the gas content test comprises oxygen, nitrogen and hydrogen, and the measurement of mechanical properties comprises tensile property, impact property, fatigue property, endurance property and performance of high-temperature alloy service requirement examination.

Technical Field

A method for quantitatively evaluating the influence of vacuum degree and oxidation products on the performance of high-temperature alloy belongs to the field of high-temperature alloy.

Background art:

the heart of the world where high temperature alloys are known as gas turbines has been the subject of attention from metallurgical workers. The preparation process of core hot-end parts such as powder high-temperature alloy turbine disks, single-crystal high-temperature alloy blades and the like of the current advanced gas turbine engines needs a key process of alloy remelting and pouring, and the remelting vacuum degree and the retention time are very important for the quality and the final service performance of the parts. In the process of development and production, corresponding processes need to be established for different parts, and the vacuum degree requirement during remelting is generally required to be provided in the process procedure. Vacuum system failure is sometimes encountered during the fabrication of the part due to incidental factors, resulting in a reduction in vacuum. Whether remelting normally occurs or the vacuum drops due to accidental factors, the alloy melt reacts with the environment at high temperature to inevitably form oxidation products, which have potential effects on the performance. Therefore, the effects of vacuum, gas content and oxidation products on the mechanical properties of the superalloy need to be quantitatively evaluated to aid in the determination of vacuum tolerance in the process.

In the prior art, the corresponding relation between the process and the alloy performance is evaluated by recording the smelting vacuum degree, measuring the average gas content (including oxygen content) of the solidified alloy and measuring the mechanical property. Practical results show that after the same alloy is smelted in a plurality of vacuum degrees with large difference, sometimes the average gas content (including oxygen content) of the alloy is not obviously different, but the mechanical property has large fluctuation, which causes difficulty in determining the relation between the process and the mechanical property and determining the tolerance of the process parameter.

By controlling the graded vacuum degree and the holding time during smelting, sequentially solidifying and aggregating the oxidation products and testing the comprehensive mechanical property of the corresponding state, the vacuum degree and the holding time, the oxidation products and the influence of the oxidation products on the mechanical property of the nickel-based superalloy are quantitatively evaluated, the type and the content of the oxidation products can be determined, a basis is provided for determining the tolerance of preparation process parameters, and technical support and guarantee are provided for preparing the high-purity superalloy, improving the qualification rate of the nickel-based superalloy parts and reducing the cost.

The invention content is as follows:

the invention relates to a method for quantitatively evaluating the influence of vacuum degree and oxidation products on the mechanical property of a high-temperature alloy, which aims to solve the problem that the influence of the vacuum degree and the mechanical property sensitivity of the oxidation products and the high-temperature alloy cannot be quantitatively measured in the past. By controlling the graded vacuum degree and sequentially solidifying and aggregating the oxidation products during smelting and matching with a method for testing the comprehensive mechanical property of the corresponding state, the vacuum degree, the oxidation products and the influence of the oxidation products on the mechanical property of the nickel-based superalloy are quantitatively evaluated, meanwhile, the type and the content of the oxidation products can be determined, a basis is provided for determining the tolerance of preparation process parameters, and technical support and guarantee are provided for preparing the high-purity superalloy, improving the qualification rate of the nickel-based superalloy parts and reducing the cost.

The purpose of the invention is realized by the following technical scheme:

the method for quantitatively evaluating the influence of the vacuum degree and the oxidation product on the performance of the high-temperature alloy is characterized by comprising the following steps of: preparing high-temperature alloy samples solidified under different vacuum conditions by controlling the graded vacuum degree and the holding time during smelting, measuring the mechanical properties of the samples under different vacuum conditions, remelting the high-temperature alloy samples under different vacuum conditions again under high vacuum, adopting sequential solidification to aggregate oxidation products, identifying the types of the oxidation products, determining the forms, components and contents of the oxidation products under different vacuum conditions, and determining and evaluating the quantitative relation of the vacuum degree and the influences of the forms, types and contents of the oxidation products on the performance of the high-temperature alloy.

The grading vacuum degree refers to different vacuum degree grades of high, medium and low, the highest vacuum degree is the ultimate vacuum degree of the equipment, and the lowest vacuum degree can reach the atmospheric environment.

The high-temperature alloy sample is obtained by remelting a cut high-temperature alloy master alloy ingot in a vacuum induction melting furnace, and placing the melt into a furnace 10 after melting and cleaning^-2Pa-10³Respectively cooling and solidifying under the conditions of different vacuum degrees of Pa and 1-100min of holding time.

The high-temperature alloy master alloy ingot is prepared by vacuum induction melting.

The sequentially solidified and aggregated oxidation product is prepared by remelting and solidifying high-temperature alloy samples under different vacuum conditions at 10 DEG C^{- 3}Pa-10^-4Remelting again in a Pa high vacuum environment, and sequentially cooling to realize sequential solidification processes of solid, solid-liquid and liquid from bottom to top respectively, so that oxidation products with relatively low density in the alloy float upwards and gather in a last solidification region on the upper surface in the sequential solidification process.

The identification of the oxidation product species is carried out by using synchrotron radiation X-ray diffraction identification.

The shape, the components and the content of the oxidation product under different vacuum conditions are determined by a scanning electron microscope and an energy spectrum, and the content of the oxidation product is determined by adopting quantitative metallographic phase.

The quantitative relationship is at 10^-2Pa-10³Pa vacuum degree, 1-100min holding time, ppm gas content and oxidation product content, and quantitative corresponding relation of high temperature alloy performance under corresponding conditions.

Before remelting again, the high-temperature alloy samples under different vacuum conditions need to be processed into gas test samples and mechanical property test bars, and gas content and mechanical property tests are respectively carried out.

The gas content test comprises oxygen, nitrogen and hydrogen, and the measurement of mechanical properties comprises tensile property, impact property, fatigue property, endurance property and performance of high-temperature alloy service requirement examination.

The technical scheme of the invention has the advantages that:

the invention prepares the high-temperature alloy samples solidified under different vacuum conditions by controlling the graded vacuum degree during smelting, and measures the mechanical properties of the samples under different vacuum conditions. Remelting high-temperature alloy samples under different vacuum conditions again under high vacuum, adopting sequential solidification to aggregate oxidation products, identifying the types of the oxidation products and determining the content of the oxidation products under different vacuum conditions. And determining and evaluating the quantitative relation of the influence of the vacuum degree, the form, the type and the content of the oxidation product on the mechanical property of the high-temperature alloy.

Firstly, controlling the graded vacuum degree during smelting, approaching to actual production, and efficiently obtaining different vacuum conditions; secondly, the oxidation product is aggregated by adopting a high-vacuum remelting sequential solidification method, so that the problems that the content of the oxidation product is extremely low and the oxidation product is too dispersed to be found and quantitatively analyzed in the prior art are solved; thirdly, quantitative analysis of oxidation products is introduced, so that the defect that the hook cannot be formed only through the average gas content and the mechanical property of the alloy in the prior art is overcome; fourthly, accurately quantifying the oxidation product by adopting a mode of combining synchrotron radiation X-rays and quantitative metallographic phase or extraction separation; fifth, the presence of oxygen (in the combined state and in the free state) can be quantitatively determined; sixthly, four key factors of vacuum degree, gas content, oxidation products and high-temperature alloy mechanical property are comprehensively considered, and a basis is provided for formulating the process parameter tolerance.

The invention solves the problem that the average gas content and the mechanical property can not be hooked due to the fact that only several factors of the vacuum degree, the average gas content (including the oxygen content) of a solidified sample and the mechanical property of the alloy are considered in the prior art.

Detailed Description

The technical solution of the present invention will be further described with reference to the following examples:

the method for quantitatively evaluating the influence of the vacuum degree and the oxidation product on the mechanical property of the high-temperature alloy solves the problem that the average gas content and the mechanical property cannot be hooked due to the fact that only the vacuum degree, the average gas content (including the oxygen content) of a solidified sample and the multiple factors of the mechanical property of the alloy are considered in the prior art, quantitative parameters of the oxidation product are introduced through remelting and sequential solidification in high vacuum, quantitative evaluation of five key factors of the vacuum degree, the holding time, the gas content, the oxidation product and the mechanical property of the high-temperature alloy is achieved, and basis is provided for determining the tolerance of preparation process parameters.

The method for quantitatively evaluating the influence of the vacuum degree and the oxidation products on the mechanical property of the high-temperature alloy comprises the following specific steps:

step one, preparing a high-temperature alloy master alloy ingot by adopting vacuum induction melting, and cutting the high-temperature alloy master alloy ingot into required weight;

remelting the master alloy ingot, placing the melt under different vacuum conditions after clearing, and respectively cooling and solidifying to obtain high-temperature alloy samples under different vacuum conditions; the different vacuum conditions were obtained by the time to shut down the vacuum pump after purging.

Thirdly, sampling the remelted and solidified high-temperature alloy samples under different vacuum conditions to test the gas content and the mechanical property; the gas content is measured by oxygen, nitrogen and hydrogen, and the mechanical properties are measured by tensile property, impact property, fatigue property and endurance property

And the performance of the service requirement evaluation of the high-temperature alloy.

Step four, polishing and cleaning the surfaces of the remelting and solidifying high-temperature alloy samples under different vacuum conditions, remelting again and sequentially solidifying under a high-vacuum environment, and aggregating oxidation products;

identifying the type of the oxidation product after the high vacuum sequential solidification and aggregation, and determining the form and the content of the oxidation product; the identification of the types of the oxidation products adopts synchrotron radiation X-ray diffraction, the morphological analysis of the oxidation products adopts a scanning electron microscope, and the quantity of the oxidation products adopts quantitative metallographic phase or extraction separation analysis.

And step six, establishing a quantitative corresponding relation among the vacuum degree, the gas content, the oxidation product amount and the mechanical property of the high-temperature alloy, and providing a basis for the tolerance selection of the process parameters.