微波烧结制备钛基复合材料及表面微弧氧化改性研究

发布时间：2018-05-07 05:52

  本文选题：钛基复合材料 + TiC　； 参考：《南昌航空大学》2017年硕士论文

【摘要】：钛基复合材料因具有优异的室温和高温力学性能等,被广泛应用于航空、航天及民用等多个工业领域。为了进一步研究不同增强相对钛基复合材料组织和性能的影响,并进一步改善其表面性能,本文采用粉末冶金结合微波烧结技术制备了TiC/Ti6Al4V和石墨烯/Ti6Al4V复合材料。研究了微波烧结温度、TiC含量对TiC/Ti6Al4V组织与力学性能、耐磨性和抗氧化性的影响,同时采用微弧氧化表面改性技术,进一步提高了TiC/Ti6Al4V复合材料的耐磨性和抗氧化性,分析了电解液组分和TiC含量对微弧氧化膜层的显微结构和性能的影响。最后研究了石墨烯作为新型增强相对钛基复合材料组织和性能的影响以及存在的一些问题。研究结果表明,微波烧结制备的TiC/Ti6Al4V复合材料由基体ɑ-Ti+β-Ti和TiC相组成,基体(ɑ-Ti+β-Ti)两相为等轴组织结构,TiC相内部处于缺C状态。随着烧结温度或者TiC含量的增加,TiC/Ti6Al4V复合材料的致密度、基体硬度、室温压缩强度均提高,得到最佳烧结工艺为烧结温度1200℃和TiC含量为15wt.%时,分别达到98.01%、661HV0.1、1789MPa。在摩擦副为GCr15或Zr O2时,复合材料的体积磨损率较基体均有不同程度的减小。随着氧化温度的增加,TiC/Ti6Al4V复合材料的氧化规律由抛物线型转变为直线型,增加复合材料中TiC含量可以增大氧化激活能,减小氧化物粒径,TiC/Ti6Al4V复合材料的抗氧化性能也越好。采用NaH2PO2+Na2SiO3电解液,可以在TiC/Ti6Al4V复合材料表面制备出主要由锐钛矿TiO2相组成的微弧氧化膜层,其耐磨性较好、腐蚀电流密度较复合材料基体低2个数量级。TiC/Ti6Al4V复合材料表面微弧氧化膜可以进一步提高复合材料高温抗氧化性能,但是随着TiC含量的增加,TiC/Ti6Al4V复合材料表面的微弧氧化膜层在高温下剥落较快。石墨烯作为增强相时,随着烧结温度的升高,石墨烯易与Ti界面反应产生细小的TiC颗粒,石墨烯/Ti6Al4V复合材料的致密度和显微硬度均增加。石墨烯表面镀铜处理,使得界面处的TiC含量反而增多,同时引入了Ti2Cu相,微量铜可以降低烧结温度,提高了石墨烯/Ti6Al4V复合材料的力学性能。
[Abstract]:Because of its excellent mechanical properties at room temperature and high temperature, titanium matrix composites have been widely used in many industrial fields such as aviation, aerospace and civil. In order to further study the effect of different reinforcement on the microstructure and properties of titanium matrix composites and further improve their surface properties, TiC/Ti6Al4V and graphene / Ti _ 6Al _ 4V composites were prepared by powder metallurgy and microwave sintering. The effects of tic content of microwave sintering temperature on the microstructure, mechanical properties, wear resistance and oxidation resistance of TiC/Ti6Al4V were studied. Meanwhile, the wear resistance and oxidation resistance of TiC/Ti6Al4V composites were further improved by micro-arc oxidation surface modification technology. The effects of electrolyte composition and TiC content on the microstructure and properties of the microarc oxide film were analyzed. Finally, the effect of graphene as a new reinforced titanium matrix composite on microstructure and properties and some problems were studied. The results show that the TiC/Ti6Al4V composites prepared by microwave sintering are composed of matrix Ti 尾 -Ti and TiC phase, and the matrix (Ti 尾 -Ti) two phases are equiaxed structure and the tic phase is in the state of lacking C. With the increase of sintering temperature or TiC content, the density, matrix hardness and room temperature compression strength of TiC- / Ti6Al4V composites are increased. The results show that the optimum sintering process is that the sintering temperature is 1200 鈩，

本文编号：1855660