Al_2O_3/SiC复相陶瓷的高温蠕变与持久强度  

CREEP AND STRESS AGEING OF Al_2O_3/SiC MULTIPHASE CERAMICS AT HIGH TEMPERATURE

作　　者：包亦望[1] 王毅敏[1] 金宗哲[1] 

机构地区：[1]中国建筑材料科学研究院,北京100024

出　　处：《硅酸盐学报》2000年第4期348-351,356,共5页Journal of The Chinese Ceramic Society

基　　金：国家自然科学基金!资助项目 ( 59672 0 2 8;59872 0 3 5)

摘　　要：采用三点弯曲方法分别研究了两种原位反应烧结的氧化铝 /碳化硅复相陶瓷在 1 0 0 0℃和 1 2 0 0℃的高温蠕变性能和失效特性 ,探讨了不同温度和加载时间对变形速率的影响 ,并分析了静载荷下高温失效机理和持久强度 .对常温力学性能和高温力学性能进行了测试 ,并对不同条件下的断口进行了显微分析和对比 .研究表明该复相陶瓷在高温静载荷下的损伤过程是由于晶界滑移引起的蠕变和微裂纹扩展以及高温氧化等因素的综合过程 ,任何一种因素单独作用或多种因素同时作用均可导致试样强度下降 .实验数据显示两参数非线性蠕变方程对该材料的高温蠕变有较好的拟合性 .本文提出了用强度衰减容限与强度衰减速率之比来预测一定条件下陶瓷的耐久性和寿命 ,这个比值越大越安全、耐久性越好 .The creep and failure behavior of two types of Al 2O 3/SiC ceramics at high temperature of 1 000 ℃ and 1 200 ℃ were studied respectively by means of three_point bending test. The influences of temperature and the length of loading time on the rate of creep were investigated. The mechanism of failure and stress aging at high temperature was analyzed for the materials under static load. The study shows that the failure of the materials tested under static load at high temperature is due to the interaction of creep and crack growth as well as oxidation. Single action or interactions of the factors result in strength degradation for the specimens. It is also found that a nonlinear creep equation with two parameters exhibits good agreement with the test data. It is proposed from this study that the lifetime of ceramic components at high temperature can be evaluated by using the ratio of the critical amount of strength degradation to the mean speed of strength degradation, i.e. the lifetime is in proportion to the ratio.

关 键 词：蠕变 强度 高温 碳化硅 氧化铝 复合陶瓷 

分 类 号：TQ174.13[化学工程—陶瓷工业] TQ174.756[化学工程—硅酸盐工业]