摘要
以SiC颗粒和纳米SiC晶须复合增韧的ZrB2为基体层,以金属Mo为界面层,采用轧膜成型和热压烧结的方法,在1950℃,1h,25MPa压力/Ar气氛的条件下,成功制备了ZrB2/Mo层状复合材料。结果表明:制备的ZrB2/Mo层状复合材料的室温断裂韧性可达9.3±0.21MPa·m1/2;通过对Mo界面层的合金化可使其抗弯强度达到400±36MPa,并且减弱了Mo层的室温脆化,克服了层状材料开裂现象。其主要增韧机制包括裂纹分叉钝化、裂纹偏转、裂纹沿界面层并行扩展等。Mo与ZrB2基体层发生界面反应生成MoB,ZrB以及Mo5SiB2,从而形成了强结合界面,影响了层状结构强韧化优越性的发挥。
ZrB2/Mo laminated composites, in which ZrB2 containing 10 vol% nano-SiC whiskers and 10 vol% SiC particles were taken as matrix layer and Mo as interfacial layer were prepared by roll-compaction and hot-pressing sintering at 1950℃ for 1 h under 20 MPa pressure in flow argon. The results show that the ZrB2/Mo laminated composites have a high fracture toughness of 9.3±0.21 MPa.m^1/2, and the bending strength can be increased to 400±36 MPa by the addition of Si and B into the Mo layers, which would avoid cracking from layer interface and improve the brittlement of Mo at room temperature. The main mechanisms of enhancing toughness are attributed to crack bluntness, crack deflection, and crack parallel propagation along interracial layers. MoB, ZrB and Mo5SiB2 were formed as the reaction among ZrB2, SiC and Mo, which would limit the increase of the strength and toughness.
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2007年第A01期841-843,共3页
Rare Metal Materials and Engineering
基金
"973"计划项目(5133102-4)
清华大学基础研究基金(Jc2003039)
关键词
二硼化锆
层状复合材料
超高温陶瓷
强韧化
Zirconium diboride
laminated composites
ultrahigh temperature ceramics
reinforcement
