摘要
ZrB2-SiC基复合材料具有比单体ZrB2更优异的抗氧化性能及力学性能,但其相对较低的韧性限制了其实际工程应用,采用微结构设计或引入增韧相是改善陶瓷材料韧性的两个有效途径。本研究采用反应热压烧结工艺,分别制备了具有独特片状ZrB2晶粒互锁结构的ZrB2-SiC复合材料和以短切碳纤维(Csf)为增韧相的Csf/ZrB2-SiC复合材料。对比研究发现,晶粒互锁结构展现出优异的自强韧化效果,使ZrB2-SiC复合材料具有较高的弯曲强度及断裂韧性,但材料表现出典型的脆性断裂特征;Csf/ZrB2-SiC复合材料弯曲强度下降,但Csf具有显著的增韧作用,不仅使材料具有较高的断裂韧性,而且临界裂纹尺寸及断裂功都得到显著提高,从而表现出非灾难性破坏模式。
ZrB2-SiC ceramics present better oxidation resistance and mechanical properties than monolithic ZrB2 ceramics. However, the small damage tolerance and poor crack growth resistance, which result in the low fracture toughness, limit the engineering application of ZrB2-SiC ceramics. Focusing on this issue, microstructure design and introduction of toughening phase are two effective approaches to improve the fracture toughness of ZrB2-SiC ceramics. In this work, ZrB2-SiC and Cf/ZrB2-SiC composites were toughened respectively by interlocking microstructure and chopped carbon fibers via reactive hot pressing. For the ZrB2-SiC composites, the interlocking microstructure formed by in-situ ZrB2 platelets presented excellent self-enhancing effect. The ZrB2-SiC composites had high bending strength and fracture toughness. However, the composite exhibited typical brittle fracture characteristics. Compared with ZrB2-SiC composite, the flexural strength of Cf/ZrB2-SiC composite decreased, but the fracture toughness was comparable with the ZrB2-SiC composite. Furthermore, the critical crack size and the work of fracture of Cf/Zr B2-SiC composites significantly improved, and the composite presented the non-catastrophic failure mode.
作者
张兆甫
沙建军
祖宇飞
代吉祥
ZHANG Zhao-Fu;SHA Jian-Jun;ZU Yu-Fei;DAI Ji-Xiang(Key Lab of Advanced Technology for Aerospace Vehicles,Dalian University of Technology,Dalian 116024,China;StateKey Lab.of Structural Analyses for Industrial Equipment,School of Aeronautics and Astronautics,Dalian University of Technology,Dalian 116024,China)
出处
《无机材料学报》
SCIE
EI
CAS
CSCD
北大核心
2019年第9期918-924,共7页
Journal of Inorganic Materials
基金
国家自然科学基金(51805069)
中国博士后科学基金(2016M600201,2018T110214,2016M601304)
辽宁省自然科学基金(20170540154)
航空科学基金(2016ZF63007)~~
关键词
超高温陶瓷
晶粒互锁结构
短切碳纤维
ZRB2-SIC
断裂性能
ultra-high temperature ceramic
interlocking microstructure
chopped carbon fiber
ZrB2-SiC
fracture property
