CN112692281B - Preparation method of secondary hardening ultrahigh-strength steel by utilizing SPS sintering and deformation - Google Patents
Preparation method of secondary hardening ultrahigh-strength steel by utilizing SPS sintering and deformation Download PDFInfo
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
- B22F3/10—Sintering only
- B22F3/105—Sintering only by using electric current other than for infrared radiant energy, laser radiation or plasma ; by ultrasonic bonding
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
- B22F3/10—Sintering only
- B22F3/1017—Multiple heating or additional steps
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
- B22F3/24—After-treatment of workpieces or articles
Abstract
The invention relates to a preparation method of secondary hardening ultrahigh-strength steel by utilizing SPS sintering and deformation, belonging to the technical field of steel material preparation. The method comprises the following steps: placing the secondary hardening ultrahigh-strength steel powder in an alloy die, and performing discharge plasma high-pressure low-temperature preforming in SPS equipment to obtain a preformed green compact; then placing the preformed green compact into a graphite mold, and sintering at low pressure and high temperature in SPS equipment to obtain a sintered green body; finally, placing the sintered blank in the center of a graphite die, and performing high-temperature compression deformation in SPS equipment to obtain a secondary hardened ultrahigh-strength steel blank; the method adopts 'spark plasma sintering-spark plasma deformation' to prepare the secondary hardening ultrahigh-strength steel, has simple operation and low energy consumption, can directly obtain the secondary hardening ultrahigh-strength steel with ultrahigh strength and good toughness, and effectively avoids subsequent complex heat treatment procedures.
Description
Technical Field
The invention relates to a method for preparing secondary hardening ultrahigh-strength steel by using SPS sintering and deformation, which combines spark plasma sintering-spark plasma deformation to prepare the secondary hardening ultrahigh-strength steel, and belongs to the technical field of steel material preparation.
Background
The secondary hardening ultrahigh-strength steel is a metal structural material with wider research and application prospects, and is widely applied to key components such as rocket engine shells, landing gears of fighters and shipboard aircraft, bulletproof armors and the like in aviation and aerospace manufacturing industries and military equipment due to the ultrahigh strength, high fracture toughness, high fatigue strength and high matching of strength and fracture toughness. Typical secondary hardened ultra high strength steels are HY180, AF1410, AerMet100 and the recently developed Ferrium M54 steel in the united states. Of these, aeromet 100 and Ferrium M54 are of interest to researchers because of their high toughness matching and excellent stress corrosion resistance.
The currently researched preparation and performance optimization means of the secondary hardening ultrahigh-strength steel mostly adopt the traditional operation routes of smelting, forging and rolling and heat treatment. However, due to the characteristics of high alloying degree, narrow control range of alloy element components and high requirement on alloy cleanliness of the secondary hardening ultrahigh-strength steel, the smelting preparation technology of the secondary hardening ultrahigh-strength steel is difficult, the preparation period is long and the energy consumption is high. In addition, the later heat treatment system of the traditional smelting method mainly comprises high-temperature austenitizing, quenching, cryogenic treatment to finish martensite transformation and high-temperature tempering M2C-type carbide is dispersed and precipitated in a martensite matrix, and austenite is reversed to form a lath martensite boundary, and the heat treatment operation is complicated.
The development and application of the secondary hardening high-strength steel are severely restricted by the high difficulty of the traditional smelting technology and the complexity of the heat treatment process. With the development of the aerospace industry and the aggravation of the severe degree of the service environment of materials, the requirement on the toughness of the secondary hardening high-strength steel is higher, and the secondary hardening high-strength steel with better performance must be developed, which inevitably requires a higher-level smelting method. The traditional smelting method can not further improve the performance of the secondary hardening high-strength steel. Therefore, it is of great significance to explore the method for preparing the secondary hardening ultrahigh-strength steel with excellent mechanical properties by using a simple and efficient preparation method.
With the development of high and new technologies, some novel preparation means of metal materials gradually emerge, such as 3D printing technology, flash firing, shock sintering and the like. The spark plasma sintering technology is also a newly developed powder rapid consolidation technology, has the advantages of high temperature rise rate and short heat preservation time, and can effectively realize the densification of materials. According to reports, the material prepared by spark plasma sintering has fine and uniform tissue structure and high density, so the material is particularly suitable for synthesizing high-performance metal materials, materials which are difficult to sinter, ceramic materials and the like. At present, the Spark Plasma Sintering (SPS) method is widely used for synthesizing ceramic materials, light metal materials and related composite materials, and excellent comprehensive properties of the materials are obtained. However, no papers and patents have been reported on the production of secondary hardened ultra high strength steels using SPS. Therefore, it is very important to explore a novel preparation method for preparing secondary hardening ultrahigh-strength steel based on spark plasma sintering.
Disclosure of Invention
In view of the above, the present invention provides a method for preparing a secondary hardened ultrahigh-strength steel by SPS sintering and transformation, the method for preparing a secondary hardened ultrahigh-strength steel by spark plasma sintering-spark plasma transformation, which is simple in operation and low in energy consumption, can directly obtain a secondary hardened ultrahigh-strength steel with ultrahigh strength and good toughness, and effectively avoids the subsequent complicated heat treatment process.
The purpose of the invention is realized by the following technical scheme.
A method for preparing secondary hardening ultrahigh-strength steel by utilizing SPS sintering and deformation comprises the following steps:
(1) performing high-pressure low-temperature preforming: placing the secondary hardening ultrahigh strength steel powder in a position with the inner diameter phi1In the hard alloy die, discharge plasma high-pressure low-temperature preforming is carried out in SPS equipment.
The specific parameters are as follows: heating to 500-600 ℃ at the heating rate of 100 ℃/min, and preserving the heat for 1-2 min at the temperature; at the moment, the axial pressure is 300MPa to 500 MPa; after preforming is finished, cooling to below 200 ℃ along with a furnace, and demolding to obtain a preformed compact;
preferably, the particle size of the powder is 25 to 50 μm.
(2) Low-pressure high-temperature sintering: cleaning the preformed compact obtained in the step (1), and then placing the preformed compact with the inner diameter phi2In the graphite mold, low-pressure high-temperature sintering is carried out in SPS equipment.
The specific sintering parameters are as follows: heating at a heating rate of 100 ℃/min to enable the sintering temperature to reach 1000-1200 ℃, and preserving heat for 10-15 min at the temperature; at the moment, the axial pressure is 40MPa to 50 MPa; and after sintering, cooling to below 200 ℃ along with the furnace, and demolding to obtain a sintered green body.
(3) High-temperature compression deformation: cleaning the sintered blank obtained in the step (2), and then placing the sintered blank with the inner diameter phi3And performing high-temperature compression deformation in SPS equipment at the center of the graphite mold.
The specific deformation parameters are as follows: heating at a heating rate of 100 ℃/min to ensure that the compression deformation temperature is 950-1050 ℃, preserving heat at the temperature for 2-3 min, ensuring that the axial pressure is 40-50 MPa, cooling to below 200 ℃ along with the furnace after the compression deformation is finished, and demolding to obtain a secondary hardening ultrahigh-strength steel blank. Wherein phi1＝Φ2，10mm≤Φ3-Φ2Less than or equal to 20 mm; preferably phi3-Φ2＝10mm。
Advantageous effects
(1) Compared with the traditional smelting preparation method, the preparation method adopted by the invention has the advantages of simple operation and low energy consumption, can directly obtain the secondary hardening ultrahigh-strength steel, has ultrahigh strength and good toughness, effectively avoids the subsequent complex heat treatment process of the traditional smelting method, and has good economy.
(2) Compared with double vacuum smelting and complex heat treatment processes adopted in the traditional smelting preparation method, the secondary hardening ultrahigh-strength steel with ultrahigh strength and good toughness can be obtained mainly through three steps of preforming, spark plasma sintering and spark plasma deformation, the toughness level of the secondary hardening ultrahigh-strength steel prepared by the traditional smelting is reached, the subsequent complex heat treatment process is avoided, and the preparation period of the material is greatly shortened.
(3) The pore defects in the sintered green body obtained in the step (2) can be effectively eliminated through the relatively low deformation temperature and short pressure maintaining time of SPS compression deformation in the step (3), and the density of the final sintered green body is improved; preferably, SPS deformation operation with the difference of the inner diameters of 10mm can ensure the compression deformation of the material and eliminate the pores in the material; and the cracking of the periphery of the material caused by overlarge compression deformation can be avoided, and the crack initiation in the material is avoided.
(4) The sheet preformed compact obtained by performing at high pressure and low temperature in the step (1) has relatively high density which can reach 85%, so that good contact among powder particles is realized, and a necessary premise is provided for realizing metallurgical bonding among the powder particles by performing at low pressure and high temperature in the step (2).
(5) It can be seen from comparative example 1 of the present invention that the twice-hardened ultrahigh-strength steel prepared by direct one-step spark plasma sintering can obtain relatively high density and tensile strength, but has a low elongation after fracture. The elongation of the secondary hardening ultrahigh-strength steel prepared in the embodiment 1 of the invention is improved to 1.9 times of that before the deformation of the discharge plasma, and meanwhile, the tensile strength is improved to a certain extent, so that the good matching of the strength and the toughness of the secondary hardening ultrahigh-strength steel is realized.
(6) The method prepares the high-performance secondary hardening ultrahigh-strength steel through 'spark plasma sintering-spark plasma deformation', and provides possibility for performance strengthening of the secondary hardening ultrahigh-strength steel and design of a secondary hardening ultrahigh-strength steel-based composite material.
Drawings
In FIG. 1, a is an optical micrograph of M54 steel prepared in comparative example 1; b is the optical micrograph of the M54 steel prepared in example 1.
Fig. 2 is a graph of engineering stress versus engineering strain for the M54 steel prepared in comparative example 1 and example 1.
Fig. 3 is a graph of engineering stress versus engineering strain for the M54 steel prepared in example 2.
Detailed Description
The invention is described in detail below with reference to the drawings and specific examples, but the invention is not limited thereto.
The following comparative examples and examples:
the Fernium M54 steel powder is provided by Jiangsu Willai New Material science and technology Limited, and the particle size range of the Fernium M54 steel powder is 25-50 mu M.
The density and compactness of the secondary hardened ultrahigh-strength steel blank prepared by the comparative example and the example are measured and calculated according to the Archimedes principle.
The Model of the SPS sintering system is Dr.Sinter, Model SPS-3.20 MK-IV.
The tensile mechanical properties are all carried out on a universal material testing machine (INSTRON 5985), and the parallel section size of a sample used for the tensile test is 12mm multiplied by 3mm multiplied by 2 mm.
And the microstructure observation is carried out by adopting a metallographic microscope, and the model of the metallographic microscope is Olympus PME-3.
Comparative example 1
(1) Low-pressure high-temperature sintering: 30g of Fernium M54 steel powder was placed in a graphite mold with an internal diameter of 30mm and sintered at low pressure and high temperature in an SPS device.
The specific sintering parameters are as follows: heating at a heating rate of 100 ℃/min to reach 1050 ℃, and keeping the temperature for 10 min; at this time, the axial pressure was 40 MPa; after sintering, cooling to below 200 ℃ along with the furnace, and demolding to obtain a sintered green body; the blank is a cylinder with the diameter of 30mm and the height of 5mm, namely M54 steel.
The secondary hardening ultrahigh-strength steel cylindrical blank obtained by the comparative example is subjected to related performance tests, and the following results are obtained:
(1) the density of the cylindrical secondary hardened ultrahigh-strength steel blank prepared by the comparative example is tested, and the density of the blank is calculated, so that the test result is shown in table 1, the density of the blank is 7.69, and the density is 96.4%.
(2) The microstructure of the cylindrical billet of the post-hardened ultrahigh-strength steel prepared by the comparative example is lath martensite with high density, but the martensite structure is blurred, and the result is shown as a in the figure 1, so that the M54 steel prepared by the direct SPS sintering of the comparative example 1 is seen, the structure of the steel is lath of the martensite with high density, and the high strength of the M54 steel is ensured. The process of sintering densification of M54 steel mainly involves transformation from mechanical engagement of powder particles to metallurgical bonding, spheronization and closure of particle contact pores. Comparative example 1M 54 steel obtained by direct SPS sintering has a relatively uniform structure, but a small amount of microscopic pores, i.e., sintering defects, are still present inside, and the existence of pores deteriorates the mechanical properties of the material.
(3) The tensile mechanical property of the cylindrical billet of the secondary hardening ultrahigh-strength steel prepared by the comparative example is tested by using a universal material testing machine, the tensile strength is 1934MPa, the elongation is 6 percent, and the engineering stress-strain curve is shown in figure 2. As can be seen from fig. 2, the M54 steel prepared by direct one-step spark plasma sintering in comparative example 1 can obtain relatively high compactness and tensile strength, but has low elongation after fracture.
Example 1
(1) Performing high-pressure low-temperature preforming: 30g of Fernium M54 steel powder was placed in a cemented carbide mould with an internal diameter of 20mm and subjected to discharge plasma high pressure low temperature pre-forming in SPS equipment.
The specific parameters are as follows: heating to 500 deg.C at a heating rate of 100 deg.C/min, maintaining at the temperature for 1min under an axial pressure of 300MPa, cooling to below 200 deg.C, and demolding to obtain the final product.
(2) Low-pressure high-temperature sintering: and (2) grinding the periphery of the preformed pressed blank obtained in the step (1) by using 400-mesh SiC sand paper, removing graphite paper on the surface layer of the pressed blank, then placing the pressed blank into a graphite die with the inner diameter of 20mm, and sintering at low pressure and high temperature in SPS equipment.
The specific sintering parameters are as follows: heating at a heating rate of 100 ℃/min to enable the sintering temperature to reach 1050 ℃, preserving heat for 10min at the temperature, enabling the axial pressure to be 40MPa, cooling to 200 ℃ along with the furnace after sintering, and demolding to obtain a cylindrical sintered blank; the blank body is a cylinder with the diameter of 20mm and the height of 12 mm.
(3) High-temperature compression deformation: and (3) grinding the periphery of the sintered blank obtained in the step (2) by using 400-mesh SiC abrasive paper, removing graphite paper and irregular parts on the surface of the sintered blank, then placing the sintered blank in the center of a graphite die with the inner diameter of 30mm, and then performing high-temperature compression deformation in SPS equipment.
The specific deformation parameters are as follows: heating at a heating rate of 100 ℃/min to ensure that the compression deformation temperature is 1000 ℃, preserving heat for 2min at the temperature, ensuring that the axial pressure is 40MPa, cooling to 200 ℃ along with the furnace after the compression deformation is finished, and demolding to obtain a secondary hardened ultrahigh-strength steel cylindrical blank; the blank is a cylinder of diameter 30mm and height 5.4mm, M54 steel, with a compression set of about 55%.
The cylindrical blanks of the twice-hardened ultrahigh-strength steel prepared in the embodiment are tested, and the test results are as follows:
(1) the density of the secondary hardened ultrahigh-strength steel cylindrical blank prepared by the embodiment is 7.94g/cm3The density is 99.5%;
(2) the microstructure of the cylindrical billet of the secondary hardening ultrahigh-strength steel prepared in the embodiment is high-density lath martensite, the martensite structure is clear, the grain size is small, and the result is shown in b in fig. 1, so that the M54 steel prepared in the embodiment 1 realizes complete metallurgical bonding, the microstructure is still high-density lath martensite, the microstructure is clear and uniform, the grain size does not have the growth tendency, and no micro-holes exist in the billet.
(3) The tensile mechanical properties of the cylindrical billet of the secondary hardening ultrahigh-strength steel prepared in the embodiment are tested by using a universal material testing machine, the tensile strength is 1997MPa, the elongation is 11%, and the test result is drawn as a stress-engineering strain curve, which is shown in figure 2. As can be seen from fig. 2, the M54 steel prepared in example 1 has an elongation rate 1.9 times higher than that before the deformation by the discharge plasma, and has good toughness; meanwhile, the tensile strength is improved to a certain degree, and the good matching of the strength and the toughness of the secondary hardening ultrahigh-strength steel is realized.
Example 2
(1) Performing high-pressure low-temperature preforming: 30g of Fernium M54 steel powder was placed in a cemented carbide mould with an internal diameter of 20mm and subjected to discharge plasma high pressure low temperature pre-forming in SPS equipment.
The specific parameters are as follows: heating to 600 ℃ at a heating rate of 100 ℃/min, preserving heat at the temperature for 2min, keeping the axial pressure at 500MPa, cooling to below 200 ℃ along with a furnace after the presintering molding is finished, and demolding to obtain a preformed compact.
(2) Low-pressure high-temperature sintering: and (2) grinding the periphery of the preformed pressed compact obtained in the step (1) by using 400-mesh SiC sand paper, removing graphite paper on the surface layer of the pressed compact, then placing the pressed compact in a graphite mould with the inner diameter of 20mm, and sintering at low pressure and high temperature in SPS equipment.
The specific sintering parameters are as follows: heating at a heating rate of 100 ℃/min to enable the sintering temperature to reach 1100 ℃, preserving heat for 15min at the temperature, enabling the axial pressure to be 50MPa, cooling to 200 ℃ along with the furnace after sintering, and demolding to obtain a cylindrical sintered blank; the billet is about 20mm in diameter and about 12mm in height.
(3) High-temperature compression deformation: and (3) grinding the periphery of the sintered blank obtained in the step (2) by using 400-mesh SiC abrasive paper, removing graphite paper and irregular parts on the surface of the blank, then placing the blank in the center of a graphite die with the inner diameter of 30mm, and then performing high-temperature compression deformation in SPS equipment.
The specific deformation parameters are as follows: heating at a heating rate of 100 ℃/min to enable the compression deformation temperature to be 1050 ℃, preserving heat for 3min at the temperature, enabling the axial pressure to be 50MPa, cooling to be below 200 ℃ along with a furnace after the compression deformation is finished, and demolding to obtain a secondary-hardened ultrahigh-strength steel cylindrical blank, wherein the blank is M54 steel with the diameter being about 5.2mm, and the compression deformation amount is about 57%.
The cylindrical blanks of the twice-hardened ultrahigh-strength steel obtained in the embodiment are tested, and the test results are as follows:
(1) the density of the secondary hardened ultrahigh-strength steel cylindrical blank prepared by the embodiment is 7.96g/cm3The density is 99.7%;
(2) the tensile mechanical property of the cylindrical billet of the secondary hardening ultrahigh-strength steel prepared by the embodiment is tested by a universal material testing machine, the tensile strength is 2048MPa, and the elongation is 8.8%; the engineering stress-strain curve is shown in fig. 3, and the tensile strength is 2048MPa, the elongation is nearly 9%, and compared with comparative example 1, the elongation is improved by nearly 50%, which shows that the M54 steel prepared in example 2 has ultrahigh strength and good toughness.
TABLE 1 comparison of Density and compactness of cylindrical blanks of post-hardened ultra-high strength steels
| Test specimen | Density/(g/cm)3) | Density/% |
| Comparative example | 7.69 | 96.4 |
| Example 1 | 7.94 | 99.5 |
| Example 2 | 7.96 | 99.7 |
Table 1 is a comparison of the density and the compactness of the cylindrical blanks of the secondary hardened ultrahigh-strength steel obtained in the comparative example, the example 1 and the example 2, and the results show that the compactness of the cylindrical blanks of the secondary hardened ultrahigh-strength steel obtained in the example 1 and the example 2 by the method combining the preforming, the spark plasma sintering and the spark plasma deformation respectively reaches 99.5% and 99.7%; the compactness (96.4%) of the secondary hardened ultrahigh-strength steel cylindrical blank is obviously higher than that of a comparative example obtained by only one-step sintering; however, the high compactness guarantees good mechanical properties of the post-hardened ultrahigh-strength steel cylindrical blank.
The present invention includes, but is not limited to, the above embodiments, and any equivalent substitutions or partial modifications made under the principle of the spirit of the present invention are considered to be within the scope of the present invention.
Claims (2)
1. The preparation method of the secondary hardening ultrahigh-strength steel by utilizing SPS sintering and deformation is characterized in that: the method comprises the following steps:
(1) performing high-pressure low-temperature preforming: placing the secondary hardening ultrahigh strength steel powder in a position with the inner diameter phi1In a hard alloy die, performing high-pressure low-temperature pre-forming by discharging plasma in SPS equipment to obtain a pre-formed green compact;
(2) low-pressure high-temperature sintering: cleaning the preformed compact, and placing the compact with an inner diameter phi2Sintering at low pressure and high temperature in a graphite mold in SPS equipment to obtain a sintered blank;
(3) high-temperature compression deformation: cleaning the sintered blank, and placing the cleaned sintered blank in a furnace with the inner diameter phi3Performing high-temperature compression deformation in SPS equipment at the center of the graphite mold;
wherein phi1=Φ2，10mm≤Φ3-Φ2≤20mm；
In the step (1):
the high-pressure low-temperature preforming specifically comprises the following steps: heating to 500-600 ℃ at a heating rate of 100 ℃/min, and keeping the temperature for 1-2 min; at the moment, the axial pressure is 300 MPa-500 MPa; after preforming is finished, cooling to below 200 ℃ along with a furnace, and demolding to obtain a preformed compact;
in the step (2):
the low-pressure high-temperature sintering specifically comprises the following steps: heating at a heating rate of 100 ℃/min to enable the sintering temperature to reach 1000-1200 ℃, and preserving heat for 10-15 min at the temperature; at the moment, the axial pressure is 40 MPa-50 MPa; after sintering, cooling to below 200 ℃ along with the furnace, and demolding to obtain a sintered green body;
in the step (3):
the high-temperature compression deformation specifically comprises the following steps: heating at a heating rate of 100 ℃/min to enable the compression deformation temperature to be 950-1050 ℃, preserving heat at the temperature for 2-3 min, enabling the axial pressure to be 40-50 MPa, cooling to below 200 ℃ along with a furnace after the compression deformation is finished, and demolding to obtain a secondary hardening ultrahigh-strength steel blank.
2. The method for preparing a secondary hardened ultrahigh-strength steel using SPS sintering and deformation as claimed in claim 1, wherein: the grain size of the secondary hardening ultrahigh-strength steel powder is 25-50 mu m.
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|---|---|---|---|---|
| JP4617027B2 (en) * | 2001-08-03 | 2011-01-19 | 富士重工業株式会社 | Method for manufacturing sintered body |
| CN101956115B (en) * | 2008-04-25 | 2012-07-04 | 西安交通大学 | Processable complex phase ceramic material and preparation method and secondary hardening heat treatment method thereof |
| CN102615280A (en) * | 2012-03-26 | 2012-08-01 | 北京工业大学 | Method for manufacturing iron-based superconductor by using SPS (Spark Plasma Sintering) technology |
| CN104313380B (en) * | 2014-10-27 | 2016-11-30 | 北京工业大学 | A kind of step sintering prepares the method for high-compactness Nanograin Cemented Carbide |
| CN105154756B (en) * | 2015-10-16 | 2017-11-07 | 中南大学 | A kind of method that discharge plasma sintering prepares ODS ferrous alloys |
| CN108660352B (en) * | 2018-05-31 | 2019-08-30 | 太原理工大学 | A kind of enhanced AlCoCrFeNi2The preparation method and application of high-entropy alloy-base neutron absorber material |
| CN109136608B (en) * | 2018-08-22 | 2020-06-09 | 北京理工大学 | Preparation method of TiB whisker reinforced titanium-based composite material with controllable orientation |
| CN110744044B (en) * | 2019-08-23 | 2022-04-12 | 南京理工大学 | Spark plasma sintering preparation method of fine-grain Ti-48Al-2Cr-8Nb titanium-aluminum alloy |
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2020
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