采用双步球磨法和放电等离子烧结技术制备细晶Ti-45Al-2Cr-2Nb- 1B-0.5Ta-0.225Y(摩尔分数,％)合金,并研究烧结温度、显微组织和力学性能之间的关系.结果表明:双步球磨粉末的颗粒形状较规则,其颗粒尺寸为20～40 μm,主要由Ti3Al和Ti3A1相组成.放电等离子烧结后的块体由主相TiAl、少量的Ti3Al相及Ti2Al和TiB2相组成.当烧结温度为900℃时,烧结块体获得的主要组织是等轴晶组织,等轴晶粒尺寸大多数在100～200nm的范围内,合金的压缩断裂强度为2769 MPa,压缩率为11.69％,抗弯强度为781 MPa;当烧结温度为1000℃时,等轴晶粒明显长大,TiB2相明显增多,合金的压缩断裂强度为2669 MPa,压缩率为17.76％,抗弯强度为652MPa.随着烧结温度的升高,合金的维氏硬度由658降低到616.压缩断口形貌分析表明,合金的断裂方式为沿晶断裂.
A fine-grained TiAl alloy with a composition of Ti-45Al-2Cr-2Nb-1 B-0.5Ta-0.225Y (mole fraction,％) was prepared by double mechanical milling(DMM) and spark plasma sintering(SPS).The relationship among sintering temperature,microstrueture and mechanical properties was studied.The results show that the morphology of double mechanical milled powder is regular with size in the range of 20 40 μm and mainly composed of TiAl and Ti3Al phases.The main phase TiA1 and few phases Ti3Al,Ti2Al and TiB2 were observed in the SPScd alloys.For samples sintered at 900 ℃,the equiaxed crystal grain microstructure is achieved with size in the range of 100-200 nm.With increasing the SPS temperature from 900 ℃ to 1000 ℃,the size of equiaxed crystal grain obviously increases,the microhardness decreases from HV658 to HV616,and the bending strength decreases from 781 MPa to 652MPa.In the meantime,the compression fracture strength also decreases from 2769 MPa to 2669 MPa,and the strain to fracture in compression increases from 11.69％ to 17.76％.On the base of analysis of fractographies,it shows that the compression fracture transform of the SPSed alloys is intergranular rupture.
参考文献
| [1] | X.J. Zhang;Q. Li;S.Y. Zhao;C.X. Gao;L. Wang;J. Zhang .Improvement In The Oxidation Resistance Of A γ-tial-based Alloy By Sol-gel Derived Al_2o_3 Film[J].Applied Surface Science: A Journal Devoted to the Properties of Interfaces in Relation to the Synthesis and Behaviour of Materials,2008(5P1):1860-1864. |
| [2] | D. Gosslar;R. Gunther;U. Hecht;C. Hartig;R. Bormann .Grain refinement of TiAl-based alloys: The role of TiB_2 crystallography and growth[J].Acta materialia,2010(20):6744-6751. |
| [3] | U. Hecht;V. Witusiewicz;A. Drevermann .Grain refinement by low boron additions in niobium-rich TiAl-based alloys[J].Intermetallics,2008(8):969-978. |
| [4] | HU D .Effect of composition on grain refinement in TiAl-based alloy[J].Intermetallics,2001,9:1037-1042. |
| [5] | G. Fanta;R. Bohn .The effect of ultrafine grained microstructures on the hot-workability of intermetallic/ceramic composites based on #gamma#-TiAl[J].Intermetallics,2001(1):45-49. |
| [6] | Rainer Gerling;Arno Bartels;Helmut Clemens .Structural characterization and tensile properties of a high niobium containing gamma TiAl sheet obtained by powder metallurgical processing[J].Intermetallics,2004(3):275-280. |
| [7] | FOROUZANMEHR N;KARIMZADEH F;ENAYATI M H .Synthesis and characterization of TiAl/α-Al2O3 nanocomposite by mechanical alloying[J].Journal of Alloys and Compounds,2009,478:257-259. |
| [8] | Y.Y. Chen;H.B. Yu;D.L.Zhang;L.H. Chai .Effect of spark plasma sintering temperature on microstructure and mechanical properties of an ultrafine grained TiAl intermetallic alloy[J].Materials Science & Engineering, A. Structural Materials: Properties, Misrostructure and Processing,2009(1/2):166-173. |
| [9] | 王天国,邵刚勤,段兴龙,史晓亮,孙鹏,李勇.高能球磨与热压烧结制备TiAl基合金[J].机械工程材料,2007(01):32-34. |
| [10] | ZHANG Wei,LIU Yong,LIU Bin,LI Hui-zhong,TANG Bei.Deformability and microstructure transformation of PM TiAl alloy prepared by pseudo-HIP technology[J].中国有色金属学报（英文版）,2010(04):547-552. |
| [11] | N. Forouzanmehr;F. Karimzadeh;M.H. Enayati .Study on solid-state reactions of nanocrystalline TiAl synthesized by mechanical alloying[J].Journal of Alloys and Compounds: An Interdisciplinary Journal of Materials Science and Solid-state Chemistry and Physics,2009(1/2):93-97. |
| [12] | 路新,何新波,李世琼,曲选辉.放电等离子烧结TiAl基合金的显微组织及力学性能[J].北京科技大学学报,2008(03):254-257. |
| [13] | 李东辉,吴玉程,李云,龚明,郑玉春.机械球磨与不同温度烧结下的TiAl合金研究[J].合肥工业大学学报（自然科学版）,2006(08):969-971,975. |
| [14] | LU X;HE X B;ZHANG B;QU X H ZHANG L GUO Z X TIAN J J .High-temperature oxidation behavior of TiAl-based alloys fabricated by spark plasma sinterin8[J].Journal of Alloys and Compounds,2009,478:220-225. |
| [15] | COURET A;MOLENAT G;GALY J;THOMAS M .Microstructure and mechanical properties of TiAl alloys consolidated by spark plasma sintering[J].Intermetallics,2008,16:1134-1141. |
| [16] | L.L. Zhao;G.Y. Li;L.Q, Zhang;J.P. Lin;X.P. Song;F. Ye;G.L. Chen .Influence of Y addition on the long time oxidation behaviors of high Nb containing TiAl alloys at 900℃[J].Intermetallics,2010(8):1586-1596. |
| [17] | 于宏宝,陈玉勇,张德良,陈艳飞.热等静压法制备细晶γ-TiAl及可成形性研究[J].稀有金属材料与工程,2008(10):1824-1827. |
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