动态压力闪烧制备Al2O3w/ZrO2复合材料的低温快速致密化机理研究

本项目针对晶须增韧陶瓷基复合材料难烧结的问题，发展全新的动态压力闪烧方法，实现了Al2O3w/ZrO2复合材料的低温快速致密化。动态压力闪烧方法是在传统闪烧的过程中施加一个振幅和频率可控的动态压力，它充分结合了闪烧的低温快速传质、低温塑性变形能力以及动态压力促进致密化、改善显微结构等优点，克服了传统闪烧方法致密度低，传统动态压力烧结方法温度高、时间长等问题，对解决陶瓷难烧结的共性问题具有重要意义。本项目将系统研究Al2O3w/ZrO2复合材料的动态压力闪烧致密化行为、优化工艺参数；探索力电热耦合场对Al2O3w/ZrO2复合材料显微结构和力学性能的影响，建立工艺-结构-性能关系，阐明动态压力闪烧的低温快速致密化机理。动态压力闪烧技术，从根本上突破了陶瓷材料传统烧结方法扩散速度慢、烧结温度高等技术瓶颈，在陶瓷制备工艺和陶瓷烧结机理方面有创新。本项目的实施将为高性能陶瓷及其复合材料的制备提供全新的思路和方法。

“Difficult to be densified” is a crucial issue for whisker toughed ceramic matrix composites. Currently, a novel dynamic pressure-assisted flash sintering (DPFS) method is proposed to overcome this issue. It’s found that Al2O3w/ZrO2 composites could be densified at low temperature and very short time. DPFS is achieved by applying a dynamic pressure during conventional flash sintering (FS), which possesses the advantages of fast matter migration and superplasticity of FS at low temperatures, as well as the enhanced densification ability of dynamic pressure sintering (DPS). Meanwhile, DPFS overcomes the disadvantages of low density of flash sintered materials and high sintering temperature & long dwell time of DPS. DPFS provides a treasurable opportunity to deal with the common issue of “difficult to be densified” of ceramics. In this project, the densification behavior of Al2O3w/ZrO2 composites by DPFS will discussed and the DPFS parameters for densification of Al2O3w/ZrO2 will be optimized too. The influence of DPFS parameters on the microstructures and mechanical properties of Al2O3w/ZrO2 composites will be addressed and the processing-structure-property relationship will be established. The low temperature and fast densification mechanisms of DPFS will be proposed too. It’s worth to note that DPFS overcomes the bottleneck issues of high temperature and slow diffusion rate of conventional sintering methods, which is with significant novelty at both ceramic processing and sintering mechanism development. If indeed DPFS is investigated, it will be benefit a lot for fabricating advanced ceramics and/or ceramic matrix composites at low temperature and fast speed.