【作者】 任萍萍；

【导师】 刘宁；

【作者基本信息】 合肥工业大学 ， 材料学， 2004， 硕士

【摘要】 氧化铝陶瓷是应用最广泛的一种结构陶瓷材料，然而其低的断裂强度、相对较差的抗热震和抗蠕变能力大大限制了它的应用。TiC具有高熔点（3067℃）和高硬度（HV=2800），在Al₂O₃陶瓷中掺入TiC后又可抑制Al₂O₃晶粒的生长，使复合陶瓷具有更高硬度和强度，而且分散的TiC粒子可以阻碍裂纹的扩展，对断裂韧性的提高也有一定的作用。 目前关于TiC-Al₂O₃复合陶瓷的研究大多数为微米级或亚微米级粉体之间的复合，纳米TiC-Al₂O₃复合陶瓷的研究还比较少见。TiC和Al₂O₃常用的复合方式是将TiC和Al₂O₃粉末机械混合，TiC-Al₂O₃复合陶瓷绝大多数采用热压烧结（HP）制备，烧结工艺一般为1600～1750℃×30MPa×1h，并且通常采用氮气或氩气作保护气氛。 本论文研究了烧结温度和原料粉末粒度对氧化铝基复合陶瓷组织和力学性能的影响。对不同粒度的原料粉末制备的Al₂O₃-TiC复合陶瓷，随着原料粉末的逐步变细，复合陶瓷的抗弯强度和断裂韧性都逐步提高，但原料粉末的细化对硬度却没有与此对应的影响。对氧化铝基体添加了不同含量的TiC，研究TiC的添加量对Al₂O₃-TiC复合陶瓷组织和性能的影响。当TiC的添加量为30wt.％时，Al₂O₃-TiC复合陶瓷有最佳的力学性能，抗弯强度为567MPa，断裂韧性为4.96MPa.m^1/2。对Al₂O₃-TiC复合陶瓷添加了少量的纳米Y₂O₃添加剂，改变Y₂O₃的添加量，研究Y₂O₃的添加对氧化铝基复合陶瓷烧结性能的影响。当Y₂O₃的添加量为0.35wt.％时，Al₂O₃-TiC复合陶瓷的致密度有所提高，但随着Y₂O₃的添加量的增加，Al₂O₃-TiC复合陶瓷的致密度却逐步降低。本论文还讨论了TiC、TiN和Ti（C，N）的添加对复合陶瓷性能的影响。更多还原

【Abstract】 Al2O3-based ceramics are essential structural materials, which have been widely used as cutting tools, because of their high strength, hardness, chemical stability and excellent wear resistance. But lower fracture toughness limits their applications. TiC ha a high melting temperature and high resistance to corrosion and oxidation. Since the addition of TiC to the AI2O3 matrix can increase some mechanical properties, the properties of TiC particles reinforced Al2O3-based ceramics were widely studied.The common method used to fabricate the Al2O3-TiC ceramics is to add TiC particles directly into Al2O3 matrix by ball milling. Preparation of Al2O3-based ceramics by HP attracts more attention. Conventional hot-pressing of Al2O3-based ceramics is carried out at 1650~ 1750C and 30 MPa for 1 h under argon atmosphere in an hot-pressing furnace.Al2O3-TiC ceramics with various size of starting powders were hot pressing using 30 wt.% TiC content. The Vickers hardness, bending strength and fracture toughness were studied. The experiment results show that the starting powders size has a significant effect on the properties of Al2O3-TiC ceramics. The Al2O3-TiC ceramics with various additions of TiC, from 15 to 35 wt.%, were manufactured. The effects of TiC particles on.the mechanical properties were studied. The experimental results show that the Al2O3-TiC ceramic with a content of 30 wt.% TiC content has the best mechanical properties. In the present study, Y2O3 was introduced into Al2O3-TiC ceramics. The experiments show that the additions of Y2O3 is effective in the densification of Al2O3-TiC ceramics with 0.35 wt.% Y2O3 content and the additions of > 0.35 wt.% Y2O3 is observed to be harmful.更多还原