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无机材料学报

无机材料学报

• 研究论文 • 上一篇    下一篇

B4C陶瓷的协同增韧

唐军; 谭寿洪; 陈忠明; 江东亮   

  1. 中国科学院上海硅酸盐研究所; 上海 200050
  • 收稿日期:1996-04-03 修回日期:1996-06-04 出版日期:1997-06-20 网络出版日期:1997-06-20

Multitoughening of B4C Composite

TANG Jun; TAN Shouhong; CHEN Zhongming; JIANG Dongliang   

  1. Shanghai Institute of Ceramics; Chinese Academy of Sciences Shanghai 200050 China
  • Received:1996-04-03 Revised:1996-06-04 Published:1997-06-20 Online:1997-06-20

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摘要： 采用热压工艺制备的B4C－35vol％TiB2复相陶瓷的断裂韧性值从单体B4C的3．6MPa.m1/2提高到6．5MPa.m1/2，引入游离碳后材料的韧性进一步提高，达7．6MPa.m1/2．显微结构观察表明，材料韧性的改善是因第二相颗粒TiB2和基体B4C之间的热膨胀系数不匹配而产生的残余应力导致的裂纹偏转和游离碳的引入产生的微裂纹协同增韧的结果．游高碳的存在削弱了界面的结合强度，在很强的残余应力的作用下，微裂纹成核并沿B4C－TiB2界面扩展．

关键词: 复相陶瓷, 裂纹偏转, 微裂纹, 协同增韧

Abstract: B4C-35vol% TiB2 composite ceramics with various amounts of free carbon hot-pressed at 2070℃ were studied. The incorporation of particulate TiB2 into B4C raised the toughness from3.6MPa.m1/2 to 6.5MPa.m1/2. A further increase of composite toughness up to 7.6MPa.m1/2 wasobtAlNed upon the addition of free carbon. SEM and TEM investigation revealed that the improvement of the composite toughness resulted from the multitoughening of both the crack deflectionassociated with the incorporation of TiB2 particles and the produced microcrack nucleated due to the strong residual stress and weak interface caused by the presence 9of free carbon in the interface and propagated along B4C－TiB2 interfaces.

Key words: composite ceramics, crack deflection, microcrack, multitoughening