阅读说明：本技术 一种抗氧化耐蚀动密封材料及其制备方法 (Oxidation-resistant corrosion-resistant dynamic sealing material and preparation method thereof ) 是由 周亮 于 2020-06-30 设计创作，主要内容包括：本发明涉及一种抗氧化耐蚀动密封材料及其制备方法,该抗氧化耐蚀动密封材料的成分为：5％～20％的钴、20％～40％的铁、其余为镍,该材料中低能晶界Σ29晶界比例高于60％,其中Σ3晶界在低ΣCSL晶界中的比例高于80％,共格Σ3晶界在Σ3晶界中的比例高于80％。技术方案中抗氧化耐蚀动密封材料以综合性能优异的CoNiFe中熵合金为基本组分,并通过晶界工程的方法,提高其作为动密封材料的抗氧化性能和耐腐蚀性能。(The invention relates to an anti-oxidation and anti-corrosion dynamic sealing material and a preparation method thereof, and the anti-oxidation and anti-corrosion dynamic sealing material comprises the following components: 5% -20% of cobalt, 20% -40% of iron and the balance of nickel, wherein the proportion of sigma 29 grain boundaries with low energy in the material is higher than 60%, the proportion of sigma 3 grain boundaries in the sigma CSL grain boundaries with low energy is higher than 80%, and the proportion of sigma 3 grain boundaries in the sigma 3 grain boundaries with low energy is higher than 80%. According to the technical scheme, the anti-oxidation corrosion-resistant dynamic sealing material takes CoNiFe entropy alloy with excellent comprehensive performance as a basic component, and the oxidation resistance and the corrosion resistance of the dynamic sealing material are improved by a grain boundary engineering method.)

1. The oxidation-resistant corrosion-resistant dynamic sealing material is characterized by comprising the following components: 5% -20% of cobalt, 20% -40% of iron and the balance of nickel, wherein the proportion of sigma 29 grain boundaries with low energy in the material is higher than 60%, the proportion of sigma 3 grain boundaries in the sigma CSL grain boundaries with low energy is higher than 80%, and the proportion of sigma 3 grain boundaries in the sigma 3 grain boundaries with low energy is higher than 80%.

2. The oxidation and corrosion resistant dynamic seal material and the method of making the same according to claim 1, wherein the method of making comprises the steps of:

the method comprises the following steps: alloy smelting;

step two: carrying out homogenization treatment;

step three: cold deformation treatment;

step four: and controlling annealing.

3. The oxidation and corrosion resistant dynamic sealing material and the preparation method thereof according to claim 2, characterized in that the first step is alloy melting, specifically, the method comprises weighing 5-20% cobalt, 20-40% iron and the rest nickel (the purity is more than 99.99%) in mass percentage as raw materials, putting the raw materials into a vacuum melting furnace, and vacuumizing to 5 × 10%^-3Pa, melting current: 250-350A, then filling argon until the pressure in the furnace is: 0.2-0.6 Pa, firstly melting a titanium ingot which is pre-placed in a vacuum arc furnace in advance to absorb oxygen remained in the titanium ingot, then striking an arc to melt the raw materials, adding magnetic stirring to repeatedly melt for 3-5 times, and melting into an ingot.

4. The oxidation and corrosion resistant dynamic seal material and the method for preparing the same according to claim 3, wherein the second step: the homogenization treatment is specifically as follows: and (3) placing the cast ingot in a tubular heat treatment furnace, vacuumizing, filling argon, circularly exhausting for 2-3 times to ensure that the tube is filled with pure argon, and preserving heat for 12-24 hours at 1000 ℃ to ensure the uniformity of alloy elements.

5. The oxidation and corrosion resistant dynamic sealing material and the preparation method thereof according to claim 3 or 4, characterized in that the step three, the cold deformation treatment, are as follows: placing the alloy ingots into an induction furnace with the set temperature of 900-1000 ℃, preserving heat for 10-60 minutes, forging the alloy ingots respectively by using an air hammer to finally obtain a cuboid forging, placing the forged alloy into the induction furnace with the set temperature of 900-1000 ℃, preserving heat for 30-60 minutes, air cooling, and then rolling the processed forging into an alloy plate with the rolling deformation of 5-75%.

6. The oxidation and corrosion resistant dynamic sealing material and the preparation method thereof according to claim 5, characterized in that the fourth step of controlled annealing is as follows: carrying out heat treatment on the rolled plate, placing the rolled plate with the deformation less than 50% in a muffle furnace at 900-1000 ℃, preserving the heat for 10-30 min, and cooling by water; and placing the alloy with the deformation of more than or equal to 50% in a muffle furnace at 600-700 ℃, preserving heat for 1-10 hours, and regulating and controlling materials with different crystal boundary types through double control of deformation and temperature.

Technical Field

The invention relates to a preparation method of a dynamic sealing material, in particular to an antioxidant corrosion-resistant dynamic sealing material and a preparation method thereof, belonging to the technical field of dynamic sealing materials.

Background

The dynamic seal is an important part of an aircraft engine and other turbomachines, and is widely applied to the fields of various aircraft engines, aeroderivative gas turbines, steam turbines, heavy-duty gas turbines, nuclear power units and the like. Dynamic seal materials typically operate under special conditions of high rotational speed, high ambient temperature or high frictional heating, which requires high corrosion and oxidation resistance. Grain boundaries, which are very important components of polycrystalline materials, have long been the focus of research by researchers, because the atoms at the grain boundaries are greatly different from the atoms in the crystal and are basically in a disordered state, which also determines the uniqueness of the grain boundaries, and the grain boundaries have great influence on not only the mechanical properties of the materials, but also the physical properties. The grain boundary structure and characteristics particularly have a large influence on creep properties, corrosion properties, and the like. Research finds that the performance of the material relative to the grain boundary can be improved by improving and optimizing the grain boundary characteristic distribution of the material. The method for greatly improving the proportion of the low-order lattice (Sigma CSL) of the material to the grain boundary by means of thermomechanical treatment and the like and optimizing the characteristic distribution of the grain boundary is grain boundary engineering. Compared with the large-angle random grain boundary, the low-sigma CSL grain boundary has lower grain boundary energy and is relatively stable, so that the aging resistance of the grain boundary is larger than that of the large-angle random grain boundary.

In recent years, a brand-new multi-principal-element alloy design mode is widely adopted in the field of metal materials, breaks through the traditional design taking single elements as main components, and adopts the design taking multiple main elements as basic components, so that the multi-principal-element alloy is prepared, and the multi-principal-element alloy is divided into medium-entropy alloy and high-entropy alloy according to the number of principal elements and the magnitude of mixed entropy at present. The high-entropy alloy quickly becomes a research hotspot, and then with the continuous and deep research, the medium-entropy alloy is found to have greater potential in terms of performance and application value. Gludovatz et al^[1]Researches find that the CrCoNi medium entropy alloy has excellent room temperature and low temperature performance. Secondly, the CoNiFe medium entropy alloy is favored by researchers due to the excellent mechanical property and corrosion resistance thereof^[2,3]. However, the oxidation resistance of the entropy alloy in FeCoNi after processing deformation is poor, and no report about the regulation and control of the oxidation resistance of the entropy alloy by a grain boundary engineering method is provided at present. The invention takes CoNiFe medium entropy alloy as a basic component, and improves the oxidation resistance and the corrosion resistance of the CoNiFe medium entropy alloy as a dynamic sealing material by a grain boundary engineering method.

[1]B.Gludovatz,A.Hohenwarter,K.V.Thurston,H.Bei,Z.Wu,E.P.George,R.O.Ritchie,Exceptional damage-tolerance of a medium-entropy alloy CrCoNi atcryogenic temperatures,Nature Conmucation 7(2016)10602.

[2]C.H.Tsau,S.X.Lin,C.H.Fang,Microstructures and corrosion behaviorsof FeCoNi and CrFeCoNi equimolar alloys,Materials Chemistry and Physics 186(2017)534-540.

[3]X.L.An,H.Zhao,T.Dai,H.G.Yu,Z.H.Huang,C.Guo,P.K.Chu,C.L.Chu,Effectsof heat treatment on the microstructure and properties of cold-forged CoNiFemedium entropy alloy,Intermetallics 110(2019)7.

Disclosure of Invention

The technical scheme provides a method for promoting a large number of low-energy grain boundaries to form (< sigma 29) through grain boundary engineering, particularly improves the proportion of coherent twin grain boundaries (coherent sigma 3 grain boundaries) in a medium-entropy alloy, reduces the free energy of an alloy system, and breaks the continuity of random high-energy grain boundaries, so that the oxidation resistance and the corrosion resistance of the CoNiFe medium-entropy alloy as the dynamic sealing material are improved.

In order to achieve the purpose, the technical scheme of the invention is as follows, and the oxidation-resistant corrosion-resistant dynamic sealing material comprises the following components: 5% -20% of cobalt, 20% -40% of iron and the balance of nickel, wherein the proportion of sigma 29 grain boundaries with low energy in the material is higher than 60%, the proportion of sigma 3 grain boundaries in the sigma CSL grain boundaries with low energy is higher than 80%, and the proportion of sigma 3 grain boundaries in the sigma 3 grain boundaries with low energy is higher than 80%.

The preparation method comprises the following steps:

the method comprises the following steps: alloy smelting;

step two: carrying out homogenization treatment;

step three: cold deformation treatment;

step four: and controlling annealing.

Further, the alloy smelting step I comprises weighing granular/blocky materials including, by mass, 5% -20% of cobalt, 20% -40% of iron and 15% -25% of nickel (the purity is greater than 99.99%), placing the materials into a vacuum smelting furnace, and vacuumizing to 5 × 10%^-3Pa, melting current: 250-350A, then filling argon until the pressure in the furnace is: 0.2-0.6 Pa, firstly melting titanium ingot pre-placed in a vacuum arc furnace in advance to absorb residual oxygen, and thenAnd (3) striking an arc to smelt the raw materials, adding magnetism, stirring, repeatedly smelting for 3-5 times, and smelting into ingots.

Further, the second step: the homogenization treatment is specifically as follows: and (3) placing the cast ingot in a tubular heat treatment furnace, vacuumizing, filling argon, circularly exhausting for 2-3 times to ensure that the tube is filled with pure argon, and preserving heat for 12-24 hours at 1000 ℃ to ensure the uniformity of alloy elements.

Further, the third step of cold deformation treatment specifically comprises the following steps: and (3) placing the alloy ingots into an induction furnace with the set temperature of 900-1000 ℃, preserving heat for 10-60 minutes, and forging the alloy ingots respectively by using an air hammer to finally obtain the cuboid forge piece. And (3) keeping the temperature of the forged alloy at 900-1000 ℃ for 30-60 minutes, and cooling in air. And then rolling the processed forge piece into an alloy plate, wherein the rolling deformation is 5-75%.

Further, the fourth step of controlling annealing specifically comprises the following steps: carrying out heat treatment on the rolled plate, placing the rolled plate with the deformation less than 50% in a muffle furnace at 900-1000 ℃, preserving the heat for 10-30 min, and cooling by water; and placing the alloy with the deformation of more than or equal to 50% in a muffle furnace at 600-700 ℃, preserving heat for 1-10 hours, and regulating and controlling materials with different crystal boundary types through double control of deformation and temperature.

Compared with the prior art, the invention has the advantages that 1) the oxidation-resistant corrosion-resistant dynamic sealing material in the technical scheme takes CoNiFe entropy alloy with excellent comprehensive performance as a basic component, and the oxidation resistance and the corrosion resistance of the dynamic sealing material are improved by a grain boundary engineering method; 2) low-energy grain boundaries Σ 29 grain boundaries) in the material is higher than 60%, wherein the proportion of Σ 3 grain boundaries in the low Σ CSL grain boundaries is higher than 80%, and the proportion of Σ 3 grain boundaries in the Σ 3 grain boundaries is higher than 80%. The method promotes a large amount of low-energy crystal boundaries to form (< sigma 29) through crystal boundary engineering, particularly improves the proportion of coherent twin crystal boundaries (coherent sigma 3 crystal boundaries) in the medium-entropy alloy, reduces the free energy of an alloy system, and simultaneously breaks the continuity of random high-energy crystal boundaries, thereby realizing the improvement of the oxidation resistance and the corrosion resistance of the dynamic sealing material.

The specific implementation mode is as follows:

for the purpose of enhancing an understanding of the present invention, the present invention will be described in detail with reference to the following examples.