振荡压力烧结制备ZrO2-Al2O3-SiC复合材料的致密化行为及强韧化机理研究

Tetragonal zirconia polycrystalline (TZP) ceramics have great potential applications in the fields of key technology and under extreme application environment. However, their low temperature degradation usually happens during the service process, and their mechanical properties are also apparently decreased at high temperatures. In view of these problems, alumina toughened zirconia ceramics will be selected as the research objects in this project using SiC nanoparticles or/and whiskers as the reinforced phases; dynamic oscillatory pressure sintering (OPS) technique will be also used for the preparation of new types of zirconia matrix composites with high strength, high toughness, high hardness and high reliability in order to meet the above requirements. Moreover, the influence of various OPS parameters on the densification, grain growth, defect removal and mechanical properties of zirconia matrix composites will be systematically investigated to indicate their sintering kinetic processes and special densification as well as strengthening and toughening mechanisms. In the meanwhile, the relationship about material compositions, sintering parameters, microstructure and mechanical properties of zirconia matrix composites prepared by OPS technique will be also explored. All the research work mentioned above provides the important theoretical and practical significance for preparing zirconia matrix composites with high performances, and enriches the sintering theory of modern ceramics.

四方氧化锆多晶体（TZP）陶瓷在诸多关键技术领域和极端应用环境有很好的应用前景。针对其在低温产生老化和高温下力学性能退化现象，造成材料的强度、韧性、硬度和可靠性难以满足使用要求，本项目以氧化铝增韧氧化锆陶瓷材料为研究对象，将碳化硅纳米颗粒和碳化硅晶须等作为增强相，拟采用振荡压力烧结新技术制备一种新型的高强度、高韧性、高硬度和高可靠性的氧化锆基复合材料。本项目系统地研究振荡压力烧结工艺条件与材料致密度、晶粒生长、缺陷结构及分布等微结构演变的相关性，揭示其对材料力学性能变化的影响规律；探明材料烧结动力学过程及晶粒生长可控的致密化机理，揭示材料的强韧化机理，从而建立振荡压力烧结材料组成-工艺条件-显微结构-力学性能之间的关系，既为制备高性能氧化锆基复合材料提供理论依据，也丰富了现代陶瓷材料的烧结理论。

本项目针对四方氧化锆多晶体陶瓷存在高温下力学性能退化和低温老化的问题，以氧化铝颗粒、碳化硅颗粒(SiCp)和碳化硅晶须(SiCw)为增强相，采用振荡压力烧结新技术制备了高强韧、高抗低温老化的ZrO2-Al2O3-SiC复合材料。重点研究了如下内容：(1)振荡压力烧结ZrO2-Al2O3复合材料致密化行为；(2)振荡压力烧结制备ZrO2-Al2O3-SiCw复合材料及其力学性能研究；(3)ZrO2-Al2O3-SiCp复合材料的振荡压力烧结行为及其力学/低温老化性能研究；(4)SiCp和SiCw复合引入对ZrO2-Al2O3-SiC复合材料致密化及力学/低温老化性能的影响。通过研究发现，SiCw的引入能够显著地提高ZrO2-Al2O3-SiCw复合材料的断裂韧性，SiCp的添加提高了ZrO2-Al2O3-SiCp复合材料的硬度，SiCw和SiCp复合引入能够使ZrO2-Al2O3-SiC复合材料保持高强高韧，其中含5vol.%SiCw和10vol.%SiCp材料还具有良好的抗低温老化的能力；同时，建立了材料组成-振荡压力烧结工艺条件-显微结构-力学性能的内在关联性，揭示了材料颗粒弥散增韧、晶须增韧以及应力诱导相变增韧的协同增韧机理。在本项目资助下，研究团队在国内外学术刊物上发表SCI收录论文16篇，申请国家发明专利2项，参加国内外学术会议8人次，培养硕士研究生5名。