Multi-element composite anti-oxidation Ti2AlNb alloy and preparation method thereof
阅读说明：本技术 一种多元素复合抗氧化Ti2AlNb合金及其制备方法 (Multi-element composite anti-oxidation Ti2AlNb alloy and preparation method thereof ) 是由 张明达 隋楠 黄旭 于 2020-04-17 设计创作，主要内容包括：本发明是一种多元素复合抗氧化Ti<Sub>2</Sub>AlNb合金及其制备方法,该合金的化学元素及其重量百分比为：Al：20％～25％,Nb：20％～23％,W：0.1％～1.5％,Zr：1％～3％,Si：0.1％～1％,Ta：0.1％～2％,W+Zr+Si+Ta：1.5％～7.5％,余量为Ti。其制备方法包括合金配料、熔炼、开坯、锻造过程,其中合金配料采取分布式高熔点合金元素合金包布置压电极方法,熔炼工艺采取三次真空自耗熔炼工艺,开坯工艺采用均匀化热处理+挤压开坯方法,锻造工艺采用多相区交替锻造方法制备。本发明通过在Ti-Al-Nb体系中加入W、Zr、Si、Ta等合金元素,结合合金成分均匀化和组织均匀化熔炼和锻造工艺,明显提高Ti<Sub>2</Sub>AlNb合金的高温抗氧化能力,同时提高强度力学性能。(The invention relates to multi-element composite anti-oxidation Ti 2 The AlNb alloy and the preparation method thereof, the alloy comprises the following chemical elements by weight percent: al: 20% -25%, Nb: 20% -23%, W: 0.1-1.5%, Zr: 1 to 3Percent, Si: 0.1% -1%, Ta: 0.1% -2%, W + Zr + Si + Ta: 1.5 to 7.5 percent, and the balance of Ti. The preparation method comprises the steps of alloy batching, smelting, cogging and forging, wherein the alloy batching adopts a method of arranging a pressure electrode in a distributed high-melting-point alloy pack, the smelting process adopts a three-time vacuum consumable smelting process, the cogging process adopts a homogenization heat treatment and extrusion cogging method, and the forging process adopts a multiphase-zone alternative forging method. According to the invention, by adding alloy elements such as W, Zr, Si, Ta and the like into a Ti-Al-Nb system and combining alloy component homogenization and structure homogenization smelting and forging processes, Ti is obviously improved 2 The high-temperature oxidation resistance of the AlNb alloy is improved, and the strength mechanical property is improved.)
1. Multi-element composite anti-oxidation Ti2An AlNb alloy characterized by: the alloy comprises the following chemical elements in percentage by weight: al: 20% -25%, Nb: 20% -23%, W: 0.1-1.5%, Zr: 1% -3%, Si: 0.1% -1%, Ta: 0.1% -2%, W + Zr + Si + Ta: 1.5 to 7.5 percent, and the balance of Ti.
2. The multi-element composite oxidation-resistant Ti of claim 12An AlNb alloy characterized by: the weight ratio of Al to Nb in the alloy is 0.95-1.1.
3. The multi-element composite oxidation-resistant Ti of claim 12An AlNb alloy characterized by: in the alloy, the weight percentage of W is 0.1-2%, and the Zr alloy element content is 1-3%.
4. The multi-element composite oxidation-resistant Ti of claim 1 or 32An AlNb alloy characterized by: in the alloy, the weight ratio of W to Zr is not more than 2.
5. The multi-element composite oxidation-resistant Ti of claim 12An AlNb alloy characterized by: in the alloy, the weight percentage of Si is 0.1-1%, and the content of Ta alloy element is 0.1-2%.
6. The multi-element composite oxidation-resistant Ti of claim 1 or 52An AlNb alloy characterized by: in the alloy, the weight ratio of Si to Ta is 0.5 or less.
7. Preparation of the multielement composite oxidation resistant Ti as claimed in claim 12The method of the AlNb alloy is characterized by comprising the following steps: the method comprises the following steps:
step one, adopting distributed arrangement of alloy packs and pressing electrodes, and preparing Ti2AlNb alloy ingots by combining multiple times of vacuum consumable melting;
step two, ingot casting homogenization heat treatment, and extrusion cogging crushing Ti2An AlNb as-cast structure;
step three, extruding the cogging Ti2And the AlNb alloy primary bar is subjected to multiphase alternate forging to refine a uniform microstructure so as to optimize comprehensive performance.
8. The method for preparing multielement composite anti-oxidation Ti according to claim 72The method of the AlNb alloy is characterized by comprising the following steps: in the step one, the step of arranging alloy bags in a distributed manner and pressing the electrodes is to prepare a plurality of small-specification alloy bags from partial Al-Nb alloy and partial W alloy by using Al foil, fully mix sponge Ti, sponge Zr, Al beans, Al-Si intermediate alloy and Al-Ta intermediate alloy, evenly arrange mixed materials and small-specification alloy bags layer by layer, ensure that the materials are evenly distributed without leaking materials, and then finish pressing the electrode blocks;
the electrode block is used for vacuum consumable melting after being welded, and Ti is melted by adopting a vacuum consumable furnace2Casting ingots for 3-4 times to obtain Ti2And (5) AlNb alloy ingot casting.
9. The method for preparing multielement composite anti-oxidation Ti according to claim 72The method of the AlNb alloy is characterized by comprising the following steps: in the step two, the ingot casting homogenization heat treatment is to carry out surface peeling and riser cutting treatment on the ingot casting obtained by smelting, then to place the ingot casting in a heat treatment furnace with the temperature of 800 ℃ for heat preservation treatment for T min, (0.4D-30) min is less than or equal to T and less than or equal to (0.4D +30) min, D is the diameter of the alloy ingot casting and is in unit mm, then to heat the heat treatment furnace to 1250 ℃ for homogenization treatment, and to preserve heat for 12-24 hours;
after homogenizing heat treatment of cast ingot, using extrusion to make blank, in Ti2Coating heat-insulating paint on the surface of the AlNb ingot, placing the AlNb ingot in a heating furnace at 1200 ℃ for heat insulation T1min, (0.4D-30) min is not less than T1 and not more than (0.4D +30) min, D is the diameter of the alloy ingot and is unit mm, spraying glass lubricant on the surface after discharging, placing the AlNb ingot in an extruder for extrusion and drawing, wherein the extrusion ratio is 3: 1-4: 1; need to be extruded in the extrusion processThe barrel is preheated to 200-300 ℃, and the extrusion speed is 100 mm/min.
10. The method for preparing multielement composite anti-oxidation Ti according to claim 72The method of the AlNb alloy is characterized by comprising the following steps: the Ti after extrusion cogging in the third step2The multiphase alternate forging of the AlNb alloy primary bar is to forge the AlNb alloy primary bar for 3-5 times at 1100-1200 ℃, then forge the AlNb alloy primary bar for 3-5 times at 1000-1100 ℃, wherein the upsetting and drawing deformation amount of each time is 35-50 percent, and the Ti is finished2Preparing an AlNb alloy bar;
the heat preservation time per firing is T2min, (0.6D-30) min is not less than T2 and not more than (0.6D +30) min, and D is the diameter of the alloy cast ingot and unit mm.
Technical Field
The invention relates to multi-element composite anti-oxidation Ti2An AlNb alloy and a preparation method thereof, belonging to the field of high-temperature titanium alloy materials.
Background
With the continuously improved application service requirements of novel aircraft engines on high-temperature titanium alloy materials, titanium alloy materials with higher high-temperature mechanical properties and oxidation resistance need to be developed urgently. The traditional high-temperature titanium alloy material is limited by high-temperature stability and oxidation resistance, so that the long-time stable use temperature of the traditional high-temperature titanium alloy material at 600-650 ℃ has great breakthrough difficulty. O-phase Ti as one of Ti-Al-Nb alloy systems2The AlNb alloy can meet the high-standard service requirement of a novel aircraft engine due to the characteristics of low density, high specific strength, excellent high-temperature mechanical property and the like, and is one of important materials for high-temperature structural materials with the temperature of more than 650 ℃.
At present, Ti2In an AlNb alloy system, the high-temperature oxidation resistance is one of important factors for restricting long-time service under the high-temperature condition. In the process of carrying out anti-oxidation research on a Ti-Al-Nb alloy system, the comprehensive anti-oxidation performance is found to be optimal when the Nb content is in the range of 10-13%, and as the Nb content is further increased, Nb generated in the high-temperature oxidation of the high-Nb alloy is increased2O5Insufficient protective power of oxide film, resulting in Ti2Reduction of oxidation resistance of AlNb alloy and Ti2Generally, more than 20% of Nb content is required in the AlNb alloy to ensure the plasticity and the processability. The development work of respectively adding alloy elements such as V, Si, Ta and the like into a Ti-Al-Nb alloy system to optimize the oxidation resistance and the comprehensive mechanical property is also researched, part of the alloy elements play a positive role in improving the oxidation resistance and the comprehensive mechanical property, but are limited by the addition content limitation and the cost limitation of a single alloy element in the Ti-Al-Nb alloy system, and the development requirement of higher comprehensive mechanical property of the Ti-Al-Nb alloy system is difficult to meet by using a single alloy component optimization design in the Ti-Al-Nb alloy system at present.
Disclosure of Invention
The invention provides multi-element composite anti-oxidation Ti2AlNb alloy and preparation method thereof, aiming at solving the technical problem of Ti2Optimizing Ti due to the deficiency of AlNb alloy in oxidation resistance and other properties2The high-temperature oxidation resistance of the AlNb alloy is considered, and the comprehensive mechanical properties such as high-temperature strength, creep endurance and the like are considered. And the state and distribution characteristics of various alloy elements are combined, a smelting process, a hot working process and a heat treatment process are designed in a targeted manner, the uniformity and stability of the various alloy elements in the material structure are ensured, and pure and uniform high-quality antioxidant Ti is prepared2AlNb alloy material.
In order to solve the technical problems, the invention provides the following technical scheme:
the technical scheme of the invention provides multi-element composite anti-oxidation Ti2An AlNb alloy characterized by: the alloy comprises the following chemical elements in percentage by weight: al: 20% -25%, Nb: 20% -23%, W: 0.1-1.5%, Zr: 1% -3%, Si: 0.1% -1%, Ta: 0.1% -2%, W + Zr + Si + Ta: 1.5 to 7.5 percent, and the balance of Ti.
In one embodiment, the weight ratio of Al to Nb in the alloy is 0.95 to 1.1.
In one implementation, the weight percentage of W in the alloy is 0.1-2%, and the content of Zr alloy element is 1-3%.
In one implementation, the weight ratio of W to Zr in the alloy is 2 or less.
In one implementation, the alloy has Si content of 0.1-1 wt% and Ta content of 0.1-2 wt%.
In one implementation, the weight ratio of Si to Ta in the alloy is 0.5 or less.
The technical scheme of the invention also provides a method for preparing the multi-element composite anti-oxidation Ti2AlNb alloy, which is characterized by comprising the following steps: the method comprises the following steps:
step one, adopting distributed arrangement of alloy packs and pressing electrodes, and preparing Ti2AlNb alloy ingots by combining multiple times of vacuum consumable melting;
step two, ingot casting homogenization heat treatment, and extrusion cogging crushing Ti2An AlNb as-cast structure;
step three, extruding the cogging Ti2And the AlNb alloy primary bar is subjected to multiphase alternate forging to refine a uniform microstructure so as to optimize comprehensive performance.
In one implementation, in the step one, the step of arranging alloy bags in a distributed manner and pressing the electrodes is to prepare a plurality of small-specification alloy bags from partial Al-Nb alloy and partial W alloy by using Al foil, fully mix sponge Ti, sponge Zr, Al beans, Al-Si intermediate alloy and Al-Ta intermediate alloy, evenly arrange the mixed materials and the small-specification alloy bags layer by layer, ensure that the materials are evenly distributed without leaking, and then finish pressing the electrode blocks;
the electrode block is used for vacuum consumable melting after being welded, and Ti is melted by adopting a vacuum consumable furnace23-4 times of AlNb alloy ingot casting, and controlling the smelting process by adopting large current to obtain Ti2And (3) turning the surface of the AlNb alloy ingot for 2-4 mm before smelting the AlNb alloy ingot.
In one implementation, the ingot casting homogenization heat treatment in the step two is to perform surface peeling and riser cutting treatment on the ingot casting obtained by smelting, then place the ingot casting in a heat treatment furnace at the temperature of 800 ℃ for heat preservation treatment for T min, (0.4D-30) min is less than or equal to T and less than or equal to (0.4D +30) min, D is the diameter of the alloy ingot casting in unit mm, then heat the heat treatment furnace to 1250 ℃ for homogenization treatment, and keep the temperature for 12-24 h;
after homogenizing heat treatment of cast ingot, using extrusion to make blank, in Ti2Coating heat-insulating paint on the surface of the AlNb ingot, placing the AlNb ingot in a heating furnace at 1200 ℃ for heat insulation T1min, (0.4D-30) min is not less than T1 and not more than (0.4D +30) min, D is the diameter of the alloy ingot and is unit mm, spraying glass lubricant on the surface after discharging, placing the AlNb ingot in an extruder for extrusion and drawing, wherein the extrusion ratio is 3: 1-4: 1; in the process of the extrusion process, the extrusion cylinder needs to be preheated to 200-300 ℃, and the extrusion speed is 100 mm/min.
In one embodiment, the extrusion of the cogging Ti in step three2The multiphase alternate forging of the AlNb alloy primary bar material is that firstly forging is carried out for 3-5 times at 1100-1200 ℃, and then forging is carried out for 3-5 times at 1000-1100 ℃, wherein each timeThe secondary upsetting and drawing deformation amount is 35 to 50 percent to finish the Ti2Preparing an AlNb alloy bar;
the heat preservation time per firing is T2min, (0.6D-30) min is not less than T2 and not more than (0.6D +30) min, and D is the diameter of the alloy cast ingot and unit mm.
The technical scheme of the invention has the following characteristics:
1. a multi-alloy-element composite design method of a Ti-Al-Nb-W-Zr-Si-Ta alloy system is adopted, a W and Zr combination for improving the anti-oxygen performance is added into the Ti-Al-Nb system, a Si element is added to improve the strength mechanical property, a Ta alloy element is used for optimizing the strength and the plastic comprehensive mechanical property, four trace alloy elements of W, Zr, Si and Ta are added into the Ti-Al-Nb ternary alloy system to be matched with each other, the oxidation resistance is improved, and the comprehensive mechanical property is optimized.
2. Aiming at the characteristics of alloy components of various alloy elements, a method of arranging a piezoelectric electrode in a distributed alloy bag is adopted, and Ti is prepared by combining large-current multiple-time vacuum consumable melting2And the AlNb alloy ingot casting ensures the smooth addition of alloy elements such as W, Si, Ta and the like.
3. The method combines homogenizing heat treatment and extrusion cogging, adopts a method of charging at 800 ℃ for heat preservation and gradually heating to 1250 ℃ for heat preservation to fully homogenize alloy components, and simultaneously adopts extrusion cogging to refine cast structure and improve the hot processing performance of the alloy.
4. To Ti after extrusion2The AlNb alloy material is subjected to multi-phase-region alternate forging, and multi-fire bar forging is sequentially performed in a B2 single-phase region, a α + B2 two-phase region and a α + B2+ O three-phase region, so that homogenization and grain refining of microstructures are ensured, Ti is optimized, and2the comprehensive mechanical property of the AlNb alloy.
Detailed Description
Table 1 is Ti2Chemical elements and weight percentages of AlNb alloy
Serial number
Chemical elements and weight percentages
1
Ti-22Al-20Nb-2W-1Zr
2
Ti-22Al-20Nb-1W-1Zr
3
Ti-22Al-20Nb-0.5W-1Zr
4
Ti-23.5Al-20Nb-1W-1Zr
5
Ti-22Al-20Nb-0.5Ta-1W-1Zr
6
Ti-22Al-20Nb-1Ta-1W-1Zr
7
Ti-22Al-20Nb-1W-1Zr-0.5Si-1Ta
8
Ti-22Al-20Nb-1W-1Zr-1Si-2Ta
Preparation of Ti described in Table 12The method for manufacturing the AlNb alloy bar comprises the following steps:
preparing raw materials such as sponge Ti, sponge Zr, Al beans, Al-Si intermediate alloy, Al-Ta intermediate alloy and W-containing alloy, preparing a plurality of 10-100 g small-specification alloy bags from partial Al-Nb alloy and W alloy by using an Al foil by adopting a distributed high-melting-point alloy bag arrangement electrode pressing method, fully mixing the sponge Ti, the sponge Zr, the Al beans, the Al-Si intermediate alloy, the Al-Ta intermediate alloy and the like, uniformly arranging the mixture and the small-specification alloy bags layer by layer to ensure uniform material distribution and no material leakage, finishing pressing of 10Kg electrode blocks, and welding a plurality of groups of electrode blocks for vacuum consumable melting;
② pairs of prepared Ti2The AlNb alloy electrode block is subjected to vacuum consumable melting for 3-4 times, and the melting process is controlled by large current of 3.5-4.0 KA, so that Ti is obtained2Turning and peeling the AlNb alloy ingot, and cutting off a riser to obtain the finished product of the ingot with the specification of phi 150 × 250 mm.
③ placing the ingot obtained by the smelting in the above steps in a heat treatment furnace with the temperature of 800 ℃ for heat preservation treatment for 60min, then heating the heat treatment furnace to 1250 ℃ for homogenization treatment, preserving the heat for 24h, cogging the ingot after the homogenization treatment by extrusion, and adding Ti2Coating heat-insulating paint on the surface of the AlNb ingot, placing the AlNb ingot in a heating furnace at 1200 ℃ for heat preservation for 60min, spraying glass lubricant on the surface of the AlNb ingot after the AlNb ingot is taken out of the heating furnace, placing the AlNb ingot in an extruder for extrusion and drawing, wherein the extrusion ratio is 3: 1, the extrusion cylinder needs to be preheated to 200-300 ℃ in the extrusion process, and the extrusion speed is 100mm/min, so that a bar material with the diameter of 90 × 600mm is obtained;
④ pairs of Ti after extrusion cogging2Segmenting the AlNb alloy primary bar, adopting multi-phase region alternative forging, forging for 3-5 times at 1100-1200 ℃, and then forging for 3-5 times at 1000-1100 ℃ to finish Ti2The AlNb alloy bar is prepared, the heat preservation time of each fire is about 60min, and the deformation amount of upsetting and drawing each fire is 35-50%.
Evaluating oxidation performance, cutting a 10 multiplied by 1.5mm oxidation test piece to carry out oxidation experiment tests at 750 ℃ and 850 ℃, wherein the oxidation weight gain of the oxidation test piece for 50-100 h at 750 ℃ and 850 ℃ is shown in table 2:
serial number
1
2
3
4
5
6
7
8
750℃
0.024
0.024
0.024
0.008
0.024
0.024
0.012
0.008
850℃
0.044
0.052
0.06
0.044
0.052
0.048
0.032
0.016
g/m2·h
The oxidation weight gain result shows that the novel oxidation resistant Ti2AlNThe oxidation resistance grades of the alloy at 750 ℃ and 850 ℃ are all complete oxidation resistance.
⑥ evaluation of Strength Properties, testing Ti of different compositions2The mechanical properties of AlNb are shown in table 3:
serial number
1
2
3
4
5
6
7
8
Rp0.2
1125
1109
1097
1186
1032
1079
1236
1442
MPa
Mechanical propertyThe results show that the novel oxidation resistance Ti2The AlNb alloy adopts a method of compounding W, Si and Ta, so that the mechanical level of strength can be obviously improved.