采用超重力下燃烧合成技术,制备出TiB_2-TiC共晶复合陶瓷.XRD、SEM与EDS结果表明,复合陶瓷主要由大量细小的TiB_2片晶均匀分布于TiC基体上的共晶组织构成,而富钛ε碳化物(Ti,Cr)C_1-x则断续分布于TiC基体间,同时在基体中还孤立分布着少量的、形态不规则的α-Al_2O_3晶粒或Al_2O_3-ZrO_2共晶团组织.高温化学反应使所有产物均呈液态,且超重力的引入诱发熔体内部Stocks流,从而获得液态Ti-Cr-C-B与液态氧化物的分层熔体,液态Ti-Cr-C-B在远离平衡态下发生共晶反应生成TiB_2-TiC共晶复合陶瓷.性能测试表明,随着B_4C+Ti+C在燃烧体系中质量分数增加,TiB_2-TiC共晶复合陶瓷相对密度和断裂韧性变化不大,分别为97%～99%与6.5～7.1 MPa·m_(1/2),而维氏硬度与弯曲强度则逐渐增加,最高可达28.6 GPa与615 MPa.
TiB_2-TiC eutectic composite ceramics were prepared by combustion synthesis under high gravity. XRD, SEM and EDS results show that TiB_2- TiC composites are mainly composed of the eutectic microstructures of TiC matrix, in which a large number of the fine TiB_2 platelet grains are dispersed uniformly; meanwhile, at the boundaries of the eutectic microstructures there discontinuously disperse the ε-carbides with the enrichment of Ti atoms, and a few of isolated, irregular α-Al_2O_3 grains and Al_2O_3-ZrO_2 colonies are also observed. Because high-temperature chemical reaction results in the full-liquid products, and the introduction of high gravity induces the Stocks flow in the melts, leading to the formation of layered melts consisting of liquid Ti - Cr - C - B and liquid oxides, it is considered that TiB_2-TiC composites grow through eutectic transformation far away from the equilibrium state. The results of properties indicate that with increasing mass fraction of B_4C+Ti+C in combustion systems, the relative density and fracture toughness of TiB_2-TiC composites are all among 97% ～99 % and 6.5～values of 28. 6 GPa and 615 MPa, respectively.
参考文献
| [1] | Zhao H,Cheng Y.Formation of TiB_2-TiC composites by reactive sintering[J].Ceram Int,1999,25(4):353-358. |
| [2] | Zhou X,Zhang S,Zhu M,et al.Investigation of TiB_2-TiC composites produced by SHS and their application in Hall -Heroult cells for aluminum electrolysis[J].Int J Self-Prop High-Temp Synth,1998,7(4):403-408. |
| [3] | Gutmanas E Y,Gotman I.Dense high-temperature ceramics by thermal explosion under pressure[J].J Eur Ceram Soc,1999,19(13/14):2381-2393. |
| [4] | Vallauri D,AtIas I C,Adrian A.TiC-TiB_2 composites:A review of phase relationships,processing and properties[J].J Eur Ceram Soc,2008,28(8):1697-1713. |
| [5] | Li J,Li F,Hu K,et al.TiB_2-TiC nanocomposite powder fabricated via high energy ball milling[J].J Eur Ceram Soc,2001,21(16):2829-2833. |
| [6] | Bhaumik S K,Divakar C,Singh A K,et al.Synthesis and sintering of TiB_2 and TiB_2-TiC composite under high pressure[J].Mater Sci Eng A,2000,279(1/2):275-281. |
| [7] | Ogwu A A,Davies T J.The densification and mechanical properties of a TiC and TiB_2 hard metal sintered with a reactive alloy binder[J].Phys Status Solidi A,1996,153(1):101-116. |
| [8] | Munir Z A,Anselmi-Tamburini U.Self-propagating high temperature synthesis of hard materials[M]// Riedel R,ed.Handbook of Ceramic Hard Materials.New York:Wiley-VCH,2003. |
| [9] | Fu Z Y,Wang H,Wang W M,et al.Composites fabricated by self-propagating high-temperature synthesis[J].J Mater Process Technol,2003,137(1-3):30-34. |
| [10] | 王业亮,傅正义,王皓,等.TiB_2-TiC复相陶瓷的结构与性能研究[J].复合材料学报,2003,20(1):22-26.Wang Yeliang,Fu Zhengyi,Wang Hao,et al.Study on the structure and properties of TiB_2-TiC multiphase ceramics[J]Acta Materiae Compositae Sinica,2003,20(1):22-26. |
| [11] | Li W J,Tu R,Goto T.Preparation of directionally solidified TiB_2-TiC eutectic composites by a floating zone method[J].Mater Lett,2006,60(6):839-843. |
| [12] | Zou B L,Shen P,Gao Z M,et al.Combustion synthesis of TIC_x TiB_2 composites with hypoeutectic,eutectic and hypereutectic microstructures[J].J Eur Ceram Soc,2008,28 (11):2275-2279. |
| [13] | Zhao Z M,Zhang L,Song YG,et al.Al_2O_3/ZrO_2(Y_2O_3) selfgrowing composites prepared by combustion synthesis under high gravity[J].Scripta Materialia,2008,58(3):207-211. |
| [14] | Agrafiotis C C,Hlavaeek V,Puszynski J A.Direct synthesis of composites and solid solutions by combustion reactions[J].Combust Sci Technol,1992,88(3/4):187-199. |
| [15] | Ordanyan S S,Unrod V I,Avgustinik A I.Reactions in the system TiC_x-TiB_2[J].Powder Metall Met Ceram,1975,14(9):729-731. |
| [16] | Beratan H R.The directional solidification and properties of the TiC-TiB_2 eutectic[D].Philadelphia,PA:Pennsylvania State University,1980. |
| [17] | Gusev A I.Phase equilibria in the ternary system titanium -boron-carbon:The sections TiC_y-TiB_2 and B_4C_y-TiB_2[J].J Solid State Chem,1997,133(1):205-210. |
| [18] | Swain M V.陶瓷的结构与性能[M].郭景坤,译.北京:科学出版社,1998:153-231. |
| [19] | Vallauri D,Shcherbakov V A,Khitev A V,et al.Study of structure formation in TiC-TiB_2-Me_xO_y ceramics fabricated by SHS and densification[J].Acta Materialia,2008,56(6):1380-1389. |
| [20] | 殷声.燃烧合成[M].北京:冶金工业出版社,2004:30-32. |
| [21] | Liang Y H,Wang H Y,Yang Y F,et al.Reaction path of the synthesis of TiC-TiB_2 in the Cu-Ti-B_4C system[J].International Journal of Refractory Metals & Hard Materials,2008,26(4):383-388. |
| [22] | Yang Y F,Wang H Y,Zhao R Y,et al.Effects of C particle size on the ignition and combustion characteristics of the SHS reaction in the 20 wt% Ni-Ti-C system[J].Journal of Alloys and Compounds,2008,460(1/2):276-282. |
| [23] | Zhang Z Q,Shen P,Jiang Q C,et al.Differential thermal analysis (DTA) on the reaction mechanism in Fe-Ti-B_4C system mechanism in FeTiB_4C system[J].Journal of Alloys and Compounds,2008,463(1/2):498-502. |
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