γTiAl基合金的脉冲电流烧结与成形性能
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摘要
γ-TiAl基合金具有低密度、高熔点、良好的高温强度以及出色的抗氧化、抗蠕变和抗疲劳性能,成为最有发展前景的航空材料之一。但是TiAl基合金塑性差、难加工的缺点限制了它的广泛应用。晶粒尺寸是影响材料性能的重要因素,以传统的铸造和热变形加工方法一般难以获得细小均匀的组织。脉冲电流辅助烧结由于其升降温速度快、烧结时间短、组织结构可控、致密度高等优点被用于制备TiAl基合金。
本文利用脉冲电流辅助烧结技术,对γ-TiAl预制合金粉进行烧结。在烧结过程中,设定了不同的烧结温度、升温速度、烧结时间等工艺参数,研究其对合金微观组织的影响。对烧结后不同组织的试样进行了高温拉伸实验,得出了不同组织对超塑性能的影响,实现了低温超塑性。在超塑性拉伸实验的基础上,对等轴近γ组织和全片层组织进行了叶片的超塑挤压模拟尝试。
脉冲电流辅助烧结:当γ-TiAl粉末升温速率分别以4.5、3.8、3、2.5、2℃/s加热到1250℃,烧结5min的条件下,分别得到了等轴细晶近γ组织、细晶双态组织、近片层组织、细全片层组织、粗全片层组织。且晶粒细小,等轴近γ组织晶粒最小为4μm。
高温拉伸实验:对烧结后不同组织的试样进行高温拉伸测试。结果表明等轴细晶组织高温拉伸性能相对最优,在950℃~1000℃,应变速率为1.040×10-4s-1~2.083×10-4s-1时获得的延伸率超过240%,最大延伸率达到437%,实现了低温超塑性。通过观察在拉伸材料上发现了孔洞,材料内的孔洞对材料的延性有一定的帮助,拉伸后期成为断裂的原因,通过断口分析,高温拉伸断口基本上为延性断裂。
叶片模拟挤压:以高温拉伸实验为指导,设计了细晶等轴近γ组织和全片层组织的高温超塑挤压试验。结果表明,等轴近γ组织在1250℃,压头速度为0.05mm/min中成形质量良好,性能得到改善。而全片层组织在1250℃,0.02mm/min压头速度下,发生了动态再结晶,形成了组织均一的等轴近γ组织,各向异性差异小,材料性能得到改善。
γ-TiAl based alloys are promising candidates for elevated temperature structural materials due to their superior characteristics, such as low density, high young’s modulus, excellent strength and oxidation resistance at elevated temperature. However, they suffer from room temperature brittleness and poor workability, hindering their applications. The grain size has a very important effect on the properties of material. However,it is difficult to prepare TiAl alloy with fine and homogeneous microstructure by traditional casting and mechanical working processes. Pulse Current Auxiliary Sintering(PCAS), because of its quick heating rate, short sintering time, controllable microstructure, high material density, is videly used to produce TiAl alloys with refined microstructure.
In this paper, TiAl based alloys from the prealloyed powder of were prepared by pulse current auxiliary sintering. In the synthesis process, influences of different parameters, including heating-up rate, sintering temperature and duration time, on obtained microstructures in sintered products were studied. Effect of microstructure on properties at elevated temperature was tested. High tensil properties were obtained at relatively low temperature. Based on the tensil properties, superplastic extrusion of blade was conducted.
Pulse Current Auxiliary Sintering: When powders were synthesized in the oven at 1250℃for 5min with heating rates of 4.5, 3.8, 3, 2.5, 2℃, near gamma, duplex, nearly lamellar, fine fully lamellar and coarse fully lamellar microstructures were obtained, correspondingly. Fine grain size was abtained. The grain size of nearγmicrostructure has reached 4μm。
Tensile testing at elevated temperature: Tensile tests of different microstructure were conducted in temperature range of 950℃~1000℃. The results showed that one with equi-axed fine grains possessed more superior elevated temperature tensile properties. When the strain rate range was 1.040×10-4s-1~2.083×10-4s-1, the obtained elongation was over 240%. The maximum elongation got to 437%. High superplastic behavior at relatively low temperatures realized. Cavities were observed in the sample after tensil tests. It is analyzed that cavities wre helpful to elongation at first. But they lead to the fracture of alloy eventually. The morphologic of the cross section showed that a majority of high temperature tensile fracture was ductile.
Imitated extrusion of blade: Based on the high temperature superplasic properties, with nearγmicrostructure and fully lamellar microstructure, models of blade were extrued at 1250 ~1350℃. The results show that when the sample with nearγ microstructures was extruded at 1250℃with the extrusion rate 0.05mm/min, good quality and improved mechanical properties were obtained. Whenγ-TiAl alloys with fully lamellar microstructures was extruded at 1250℃with the extrusion rate 0.02mm/min, dynamic recrystallization happened. The microstructure transferred to equiaxial and uniformγ-TiAl with nearγmicrostructures. The properties of the material were improved.
本文利用脉冲电流辅助烧结技术,对γ-TiAl预制合金粉进行烧结。在烧结过程中,设定了不同的烧结温度、升温速度、烧结时间等工艺参数,研究其对合金微观组织的影响。对烧结后不同组织的试样进行了高温拉伸实验,得出了不同组织对超塑性能的影响,实现了低温超塑性。在超塑性拉伸实验的基础上,对等轴近γ组织和全片层组织进行了叶片的超塑挤压模拟尝试。
脉冲电流辅助烧结:当γ-TiAl粉末升温速率分别以4.5、3.8、3、2.5、2℃/s加热到1250℃,烧结5min的条件下,分别得到了等轴细晶近γ组织、细晶双态组织、近片层组织、细全片层组织、粗全片层组织。且晶粒细小,等轴近γ组织晶粒最小为4μm。
高温拉伸实验:对烧结后不同组织的试样进行高温拉伸测试。结果表明等轴细晶组织高温拉伸性能相对最优,在950℃~1000℃,应变速率为1.040×10-4s-1~2.083×10-4s-1时获得的延伸率超过240%,最大延伸率达到437%,实现了低温超塑性。通过观察在拉伸材料上发现了孔洞,材料内的孔洞对材料的延性有一定的帮助,拉伸后期成为断裂的原因,通过断口分析,高温拉伸断口基本上为延性断裂。
叶片模拟挤压:以高温拉伸实验为指导,设计了细晶等轴近γ组织和全片层组织的高温超塑挤压试验。结果表明,等轴近γ组织在1250℃,压头速度为0.05mm/min中成形质量良好,性能得到改善。而全片层组织在1250℃,0.02mm/min压头速度下,发生了动态再结晶,形成了组织均一的等轴近γ组织,各向异性差异小,材料性能得到改善。
γ-TiAl based alloys are promising candidates for elevated temperature structural materials due to their superior characteristics, such as low density, high young’s modulus, excellent strength and oxidation resistance at elevated temperature. However, they suffer from room temperature brittleness and poor workability, hindering their applications. The grain size has a very important effect on the properties of material. However,it is difficult to prepare TiAl alloy with fine and homogeneous microstructure by traditional casting and mechanical working processes. Pulse Current Auxiliary Sintering(PCAS), because of its quick heating rate, short sintering time, controllable microstructure, high material density, is videly used to produce TiAl alloys with refined microstructure.
In this paper, TiAl based alloys from the prealloyed powder of were prepared by pulse current auxiliary sintering. In the synthesis process, influences of different parameters, including heating-up rate, sintering temperature and duration time, on obtained microstructures in sintered products were studied. Effect of microstructure on properties at elevated temperature was tested. High tensil properties were obtained at relatively low temperature. Based on the tensil properties, superplastic extrusion of blade was conducted.
Pulse Current Auxiliary Sintering: When powders were synthesized in the oven at 1250℃for 5min with heating rates of 4.5, 3.8, 3, 2.5, 2℃, near gamma, duplex, nearly lamellar, fine fully lamellar and coarse fully lamellar microstructures were obtained, correspondingly. Fine grain size was abtained. The grain size of nearγmicrostructure has reached 4μm。
Tensile testing at elevated temperature: Tensile tests of different microstructure were conducted in temperature range of 950℃~1000℃. The results showed that one with equi-axed fine grains possessed more superior elevated temperature tensile properties. When the strain rate range was 1.040×10-4s-1~2.083×10-4s-1, the obtained elongation was over 240%. The maximum elongation got to 437%. High superplastic behavior at relatively low temperatures realized. Cavities were observed in the sample after tensil tests. It is analyzed that cavities wre helpful to elongation at first. But they lead to the fracture of alloy eventually. The morphologic of the cross section showed that a majority of high temperature tensile fracture was ductile.
Imitated extrusion of blade: Based on the high temperature superplasic properties, with nearγmicrostructure and fully lamellar microstructure, models of blade were extrued at 1250 ~1350℃. The results show that when the sample with nearγ microstructures was extruded at 1250℃with the extrusion rate 0.05mm/min, good quality and improved mechanical properties were obtained. Whenγ-TiAl alloys with fully lamellar microstructures was extruded at 1250℃with the extrusion rate 0.02mm/min, dynamic recrystallization happened. The microstructure transferred to equiaxial and uniformγ-TiAl with nearγmicrostructures. The properties of the material were improved.
引文
1 D.M.Dimiduk , D.B.Miracle and C.H.Ward . Development of intermetallic materials for aerospace systems.Materials Seience and Teehnology.1992,8(4):367~375
2 F.H.Fores , C.Suryanarayana , D.Eliezer . Review synthesis properties and applications of titanlum aluminides.Journal of Materials Science.1992,27:5113~5140
3 P .Bartolotta,J .Barret,T .Kelly,R .Smashey.The use of cast Ti-48Al-2Cr-2Nb in jet engines.Journal of the Minerals, Metals and Materials Society.1997,49(5):48~50
4 F.H.Froes , C.Suryanarayana , D.Eliezer . Production , characteristics and commercialization of titanium aluminides.ISIJ International,1991,31(10):1235~1248
5闰蕴琪,张振棋,周廉.γ-TiAl金属间化合物研究现状与未来展望.材料导报.2000,14(2):31~33
6 V. Bauer,H.-J. Christ.Thermomechanical fatigue behaviour of a third generationγ-TiAl intermetallic alloy.Intermetallics.2009,17:370~377
7 AlainCouret,GuyMole′nat,JeanGaly.Microstructures and mechanical properties of TiAl alloys consolidated by spark plasma sintering.Intermetallics.2008,16:1134~1141
8高一平.粉末冶金新技术——电火花烧结.冶金工业出版社.1992:1
9刘咏,黄伯云,周科朝等.粉末冶金γ-TiAl基合金研究的最新进展.航空材料学报.2001,21(4):50~55
10李宝辉.含钇的TiAl基合金显微组织及性能的研究.哈尔滨工业大学博士学位论文.2007
11彭超群,黄伯云,贺跃辉.TiAI基合金的工艺显微组织力学性能关系.中国有色金属学报,2001,11(4):527
12 C. Mercer,W .O .Soboyejo.An investigation of the fatigue and fracture behavior of mn-containing gamma titanium aluminides.Metallurgical and Materials Transactions A.1995,26:2275~2291
13 W. O. Soboyejo,D. S. Schwartz,S. M. L. Sastry.An Investigation of the fracturebehavior of gamma-based titanium aluminides: Effects of annealing in theα+γandα2 +γphase fields.Metallurgical and Materials Transactions A.1992,23A:2039
14彭超群,黄伯云,贺跃辉.TiAI基合金的工艺显微组织力学性能关系.中国有色金属学报,2001,11(4):533
15张永刚,韩雅芳,陈国良,郭建亭.金属间化合物结构材料.北京:国防工业出版社.2003:700~719
16 M.S. Vassiliou,C.G. Rhodes,M.R. Mitchell,J. Graves.Metastable Microstructure in Dynamically ConsolidatedγTitanium Aluminide.Scripta Metallurgica.1989,23(10):1791~1794
17陈玉勇,孔凡涛.TiAl基合金新材料研究及精密成形.金属学报.2002,38(11):1141~1148
18路新,赵丽明,曲选辉.粉末冶金TiAl金属间化合物的研究进展.材料导报.2006,20(8):69~71
19路新,何新波,李世琼等.放电等离子烧结TiAl基合金的显微组织及力学性能.北京科技大学学报. 2008,30(3):254~257
20姚可夫,王沛玉.脉冲电流对金属材料塑性变形呵组织结构与性能的影响.机械强度.2003,25(3):340~342
21 Ke-Fu Yao,Jun Wang. A research on electroplastic effects in wire-drawing process of an austenitic stainless steel.Scripta Materialia.45(2001):533~539
22 H.Conrad.et al.Influence of an electric or magnetic field on the liquid-solid transformation in materials and on the microstructure of solid.Materials Science and Engineering.2000,A287:205
23 J.P.Bamak,H.Conrad et al.Colony size reduction in eutectic Pb-Sn casting by eletroplusing.Materials Science and Engineering.1995,32(6):879
24 H. Conrad,J. White,W. D. Cao,Lu X P, Sprecher A F.Effect of electrie current pulseson fatigue characteristics of poly crystalline copper.Materials Science and Engineering.1991,145A:1~12
25 Z. H. Lai,C. X. Ma,H. Conrad.Cyclic softening by high density electrie current pulses during low cycle fatigue of a-Ti.Scripta Metall Materialia,1992,27:
527~531
26 Z.S .Xu,Z.H.Lai,Y. X. Chen.Effect of electric current on the recrystallizationbehavior of cold worked a-Ti.Scripta Metall.1998,22:187~190
27 Yizhou Zhou,Jingdong Guo.et al.Crack healing in a steel by using electropulsing techinque.Materials Letters.2004,58:1732~1736
28姚可夫,孟令通.脉冲电流对TiAl金属间化合物力学性能的影响.2004年中国材料研讨会论文摘要集.2004
29马垚,周张健.放电等离子烧结(SPS)制备金属材料研究进展.材料导报.2008,22(7):60~64
30高一平.粉末冶金新技术——电火花烧结.冶金工业出版社.1992:1~45
31路新,何新波,曲选辉等.放电等离子烧结快速制备致密Ti-Al基合金.金属热处理.2007,32(2):20~22
32 T. Soma,A. Sawaoka,S. Saito. Characterization of Wurtzite Type Boron Nitride Synthesized by Shock Compression.Materials Research Bulletin.1974,9(6):755~762
33 S.Kishimoto,N. Shinya.Compressive Behavior of Micro-metallic Closed Cellular Materials Fabricated by Spark-Plasma Sintering . Materials Science and Enginnering A.2008,483-484:679~682
34张久兴,刘科高,周美玲.放电等离子烧结的发展和应用.功能材料.2001,增刊:1593~1598
35 Y.M.Kim.,Studies on droplet-turbulence interactions.Journal of the Minerals, Metals and Materials Society.1994,46(7):30
36 C.Koepee,A.Bartels,General aspects of the thermomechanical.Metallurgical and Materials Transactions A.1993,24A:1795
37鲁世强,黄伯云,贺跃辉.TiAl基金属间化合物的超塑性研究现状.南昌航空工业学院学报.2001,15(4):6~10
38吴诗惇．金属超塑性变形理论．国防工业出版社．1997:7
39孙业英主编.光学显微分析.清华大学出版社.2003:220~221
40路新,何新波,李世琼等.放电等离子烧结TiAl基合金的显微组织及力学性能.北京科技大学学报.2008,30(3):254~257
41 J.J. Valencia,C. McCullough, C.G. Levi, R. Mehrabian.Solidification Microstructure of Supercooled Ti-Al Alloys Containing Intermetallic Phases.Acta Metallurgica.1989,37(9):2517~2530
42 R.H. Fan,B. Liu,J.D. Zhang,J.Q. Bi,Y.S. Yin.Kinetic Evaluation of CombustionSynthesis 3TiO2+7Al→3TiAl+2Al2O3 Using Non-isothermal DSC Method. Materials Chemistry and Physics.2005,91(1):140~145
43贺跃辉,黄伯云,曲选辉,刘业翔.TiAl基合金双温热处理原理及其相变特征的研究.中南工业大学学报.1996,27(3):298~302
44黄立国,高志玉,张志明.直流电场对A1-10%Si亚共晶合金凝固组织的影响.铸造技术.2009,30(5):650~652
45冯旭东,袁庆龙,曹晶晶,苏志俊.TiAl基合金研究进展.航天制造技术.2009,(3):35~38
46 F. Appel,R. Wagner.Microstructure and Deformation of Two-phaseγ-Titanium Aluminides.Materials Science and Engineering R.1998,22:187~268
47刘军,佘正国.粉末冶金与陶瓷成型技术.化学工业出版社.2005:81
48任学平,康永林.粉末塑性加工原理及其应用.冶金工业出版社.1998
49张俊红.TiAl基合金的组织超塑性研究.中南大学博士学位论文.2003:10
50文九巴,杨蕴林,杨永顺等.超塑性应用技术.机械工业出版社.2005:1~16
51 M.F Ashby,R.A Verrall.Diffusion-accommodated Flow and Superplasticity.Acta Metallurgica et Materialia.1973,21:149~163
52钟群鹏,赵子华.断口学.高等教育出版社,2006:176~177
53陈荣章.航空铸造涡轮叶片合金和工艺发展的回顾与展望.航空制造技术.2002(2):19~23
54林兆荣.金属超塑性成形原理及应用.航空工业出版社.1990:4~25
2 F.H.Fores , C.Suryanarayana , D.Eliezer . Review synthesis properties and applications of titanlum aluminides.Journal of Materials Science.1992,27:5113~5140
3 P .Bartolotta,J .Barret,T .Kelly,R .Smashey.The use of cast Ti-48Al-2Cr-2Nb in jet engines.Journal of the Minerals, Metals and Materials Society.1997,49(5):48~50
4 F.H.Froes , C.Suryanarayana , D.Eliezer . Production , characteristics and commercialization of titanium aluminides.ISIJ International,1991,31(10):1235~1248
5闰蕴琪,张振棋,周廉.γ-TiAl金属间化合物研究现状与未来展望.材料导报.2000,14(2):31~33
6 V. Bauer,H.-J. Christ.Thermomechanical fatigue behaviour of a third generationγ-TiAl intermetallic alloy.Intermetallics.2009,17:370~377
7 AlainCouret,GuyMole′nat,JeanGaly.Microstructures and mechanical properties of TiAl alloys consolidated by spark plasma sintering.Intermetallics.2008,16:1134~1141
8高一平.粉末冶金新技术——电火花烧结.冶金工业出版社.1992:1
9刘咏,黄伯云,周科朝等.粉末冶金γ-TiAl基合金研究的最新进展.航空材料学报.2001,21(4):50~55
10李宝辉.含钇的TiAl基合金显微组织及性能的研究.哈尔滨工业大学博士学位论文.2007
11彭超群,黄伯云,贺跃辉.TiAI基合金的工艺显微组织力学性能关系.中国有色金属学报,2001,11(4):527
12 C. Mercer,W .O .Soboyejo.An investigation of the fatigue and fracture behavior of mn-containing gamma titanium aluminides.Metallurgical and Materials Transactions A.1995,26:2275~2291
13 W. O. Soboyejo,D. S. Schwartz,S. M. L. Sastry.An Investigation of the fracturebehavior of gamma-based titanium aluminides: Effects of annealing in theα+γandα2 +γphase fields.Metallurgical and Materials Transactions A.1992,23A:2039
14彭超群,黄伯云,贺跃辉.TiAI基合金的工艺显微组织力学性能关系.中国有色金属学报,2001,11(4):533
15张永刚,韩雅芳,陈国良,郭建亭.金属间化合物结构材料.北京:国防工业出版社.2003:700~719
16 M.S. Vassiliou,C.G. Rhodes,M.R. Mitchell,J. Graves.Metastable Microstructure in Dynamically ConsolidatedγTitanium Aluminide.Scripta Metallurgica.1989,23(10):1791~1794
17陈玉勇,孔凡涛.TiAl基合金新材料研究及精密成形.金属学报.2002,38(11):1141~1148
18路新,赵丽明,曲选辉.粉末冶金TiAl金属间化合物的研究进展.材料导报.2006,20(8):69~71
19路新,何新波,李世琼等.放电等离子烧结TiAl基合金的显微组织及力学性能.北京科技大学学报. 2008,30(3):254~257
20姚可夫,王沛玉.脉冲电流对金属材料塑性变形呵组织结构与性能的影响.机械强度.2003,25(3):340~342
21 Ke-Fu Yao,Jun Wang. A research on electroplastic effects in wire-drawing process of an austenitic stainless steel.Scripta Materialia.45(2001):533~539
22 H.Conrad.et al.Influence of an electric or magnetic field on the liquid-solid transformation in materials and on the microstructure of solid.Materials Science and Engineering.2000,A287:205
23 J.P.Bamak,H.Conrad et al.Colony size reduction in eutectic Pb-Sn casting by eletroplusing.Materials Science and Engineering.1995,32(6):879
24 H. Conrad,J. White,W. D. Cao,Lu X P, Sprecher A F.Effect of electrie current pulseson fatigue characteristics of poly crystalline copper.Materials Science and Engineering.1991,145A:1~12
25 Z. H. Lai,C. X. Ma,H. Conrad.Cyclic softening by high density electrie current pulses during low cycle fatigue of a-Ti.Scripta Metall Materialia,1992,27:
527~531
26 Z.S .Xu,Z.H.Lai,Y. X. Chen.Effect of electric current on the recrystallizationbehavior of cold worked a-Ti.Scripta Metall.1998,22:187~190
27 Yizhou Zhou,Jingdong Guo.et al.Crack healing in a steel by using electropulsing techinque.Materials Letters.2004,58:1732~1736
28姚可夫,孟令通.脉冲电流对TiAl金属间化合物力学性能的影响.2004年中国材料研讨会论文摘要集.2004
29马垚,周张健.放电等离子烧结(SPS)制备金属材料研究进展.材料导报.2008,22(7):60~64
30高一平.粉末冶金新技术——电火花烧结.冶金工业出版社.1992:1~45
31路新,何新波,曲选辉等.放电等离子烧结快速制备致密Ti-Al基合金.金属热处理.2007,32(2):20~22
32 T. Soma,A. Sawaoka,S. Saito. Characterization of Wurtzite Type Boron Nitride Synthesized by Shock Compression.Materials Research Bulletin.1974,9(6):755~762
33 S.Kishimoto,N. Shinya.Compressive Behavior of Micro-metallic Closed Cellular Materials Fabricated by Spark-Plasma Sintering . Materials Science and Enginnering A.2008,483-484:679~682
34张久兴,刘科高,周美玲.放电等离子烧结的发展和应用.功能材料.2001,增刊:1593~1598
35 Y.M.Kim.,Studies on droplet-turbulence interactions.Journal of the Minerals, Metals and Materials Society.1994,46(7):30
36 C.Koepee,A.Bartels,General aspects of the thermomechanical.Metallurgical and Materials Transactions A.1993,24A:1795
37鲁世强,黄伯云,贺跃辉.TiAl基金属间化合物的超塑性研究现状.南昌航空工业学院学报.2001,15(4):6~10
38吴诗惇．金属超塑性变形理论．国防工业出版社．1997:7
39孙业英主编.光学显微分析.清华大学出版社.2003:220~221
40路新,何新波,李世琼等.放电等离子烧结TiAl基合金的显微组织及力学性能.北京科技大学学报.2008,30(3):254~257
41 J.J. Valencia,C. McCullough, C.G. Levi, R. Mehrabian.Solidification Microstructure of Supercooled Ti-Al Alloys Containing Intermetallic Phases.Acta Metallurgica.1989,37(9):2517~2530
42 R.H. Fan,B. Liu,J.D. Zhang,J.Q. Bi,Y.S. Yin.Kinetic Evaluation of CombustionSynthesis 3TiO2+7Al→3TiAl+2Al2O3 Using Non-isothermal DSC Method. Materials Chemistry and Physics.2005,91(1):140~145
43贺跃辉,黄伯云,曲选辉,刘业翔.TiAl基合金双温热处理原理及其相变特征的研究.中南工业大学学报.1996,27(3):298~302
44黄立国,高志玉,张志明.直流电场对A1-10%Si亚共晶合金凝固组织的影响.铸造技术.2009,30(5):650~652
45冯旭东,袁庆龙,曹晶晶,苏志俊.TiAl基合金研究进展.航天制造技术.2009,(3):35~38
46 F. Appel,R. Wagner.Microstructure and Deformation of Two-phaseγ-Titanium Aluminides.Materials Science and Engineering R.1998,22:187~268
47刘军,佘正国.粉末冶金与陶瓷成型技术.化学工业出版社.2005:81
48任学平,康永林.粉末塑性加工原理及其应用.冶金工业出版社.1998
49张俊红.TiAl基合金的组织超塑性研究.中南大学博士学位论文.2003:10
50文九巴,杨蕴林,杨永顺等.超塑性应用技术.机械工业出版社.2005:1~16
51 M.F Ashby,R.A Verrall.Diffusion-accommodated Flow and Superplasticity.Acta Metallurgica et Materialia.1973,21:149~163
52钟群鹏,赵子华.断口学.高等教育出版社,2006:176~177
53陈荣章.航空铸造涡轮叶片合金和工艺发展的回顾与展望.航空制造技术.2002(2):19~23
54林兆荣.金属超塑性成形原理及应用.航空工业出版社.1990:4~25
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