Development of Hybrid-Type Ceramic Matrix Composites Based on Fail-Safe Concept

基于故障安全概念的混合型陶瓷基复合材料的开发

基本信息

批准号：
05302049
负责人：
KISHI Teruo
金额：
$ 14.02万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Co-operative Research (A)
财政年份：
1993
资助国家：
日本
起止时间：
1993 至 1995
项目状态：
已结题

项目摘要

Fracture toughness of high-strength ceramics can be improved through the microstructure control and composite reinforcement. Nano-size-particle-dispersed composites are most promising among other candidate materials. The following three types of alumina based hybrid-type nano-composites were investigated through this study, in order to demonstrate the fundamental mechanism of nano-size intragranular dispersion and the contollability of the micructure by intergranular dispersion.(1) Al_2O_3/5vol% Nano-Size SiC Dispersed Composites : Although very small SiC particles tended to exist within alumina grains, larger ones are dispersed at grain boundaries. The dispersion process of nano-size particles was closely related with the degree of alumina matrix densification. The grain size of alumina could be contolled by carefully selecting the size of reinforcing particles.Both strength and toughness were improved through nano-size particle dispesion.(2) Al_2O_3/SiC/YAG Hybrid Composites : Micron-size YAG and nano-size SiC particles were successfully dispersed to fabricate Al_2O_3/SiC/YAG Hybrid Composites. Since the grain growth of alumina was controlled and homogeneous microstrucure was accomplished, the mechanical properties were much improved through hybritization.(2) Al_2O_3/LaAl_<11>O_<18> Composites : Alumina matrix composites with elongated fiber-like reinforcing phases were sucessfully fabricated. Both strength and fracture toughness increased as the volume fraction increased. In particular, the fracture toughness was much improved through the increase in the aspect ratio of reinforcement. Bridging and crack deflection contributed the toughness improvement to a large extent.

通过微观结构控制和复合增强可以提高高强陶瓷的断裂韧性。纳米颗粒分散复合材料是其他候选材料中最有前途的。本研究对以下三种氧化铝基杂化型纳米复合材料进行了研究，以论证纳米尺寸晶内分散的基本机理以及晶间分散对微结构的控制能力。(1) Al_2O_3/5vol% Nano -尺寸 SiC 分散复合材料：虽然非常小的 SiC 颗粒往往存在于氧化铝晶粒内，但较大的 SiC 颗粒分散在晶界处。纳米粒子的分散过程与氧化铝基体的致密化程度密切相关。通过仔细选择增强颗粒的尺寸可以控制氧化铝的晶粒尺寸。通过纳米尺寸颗粒的分散可以提高强度和韧性。(2) Al_2O_3/SiC/YAG 杂化复合材料：微米尺寸的 YAG 和纳米尺寸的 SiC成功地分散颗粒以制备Al_2O_3/SiC/YAG杂化复合材料。由于控制了氧化铝的晶粒生长并实现了均匀的微观结构，因此通过杂化作用大大提高了机械性能。（2）Al_2O_3/LaAl_<11>O_<18>复合材料：成功地制备了具有细长纤维状增强相的氧化铝基复合材料。捏造的。随着体积分数的增加，强度和断裂韧性均增加。特别是，通过增加增强材料的长径比，断裂韧性得到了很大的提高。桥连和裂纹偏转在很大程度上促进了韧性的提高。