干燥和潮湿环境对牙科陶瓷循环载荷下亚临界裂纹扩展的影响  

Effects of dry and wet environment on the subcritical crack growth of dental ceramics under cyclic loading

作　　者：张志升 肖云 李水根 苏剑生[2] 刘伟才[2] 

机构地区：[1]厦门市口腔医院修复科,361003 [2]上海同济大学口腔医学院

出　　处：《实用口腔医学杂志》2014年第3期340-343,共4页Journal of Practical Stomatology

基　　金：福建省卫生厅青年科研课题(编号:2012-2-102)

摘　　要：目的:研究口腔临床修复中常用的玻璃渗透氧化铝陶瓷(In-Ceram Alumina,IA)在干燥环境和潮湿环境下的亚临界裂纹扩展(以下简称SCG)行为的区别。方法:通过三点弯曲强度测量方法测得15个IA样本的强度数据,采用循环疲劳测试法测试干燥环境以及在潮湿环境下各15个IA样本的循环疲劳断裂次数数据;SCG行为通过裂纹扩展速率V和应力强度因子(K1)的函数关系来描述。结果:2种环境下IA在循环载荷下都发生亚临界裂纹扩展后导致材料断裂,在干燥环境下应力强度因子K1为临界应力因子KIC的46%时发生裂纹传播;在潮湿环境下应力强度因子K1为临界应力因子KIC的40%时发生裂纹传播。结论:IA在循环载荷下存在SCG行为,当应力强度因子相同时,潮湿环境下样品的裂纹扩展速率较大。Objective： To study the subcritical crack growth（SCG） of glass-infihrated alumina-based In-Ceram Alumina（IA） under cyclic loading in dry and wet environment. Methods： 45 bar-shaped specimens of IA were fabricated and loaded in three-point bending （3p） （ n = 15 ） and cyclic fatigued （F） in dry（ n = 15 ） and wet（ n = 15 ） conditions respectively. The initial σ and the number of cycles to fracture were obtained from 3p and F test respectively, the behavior of SCG was described in terms of crack velocity as a function of stress intensity factor（K1）. Results ： IA was prone to SCG with crack propagation at K1 as low as 46% and 40% of its critical stress intensity factor（ KIC ） in dry and wet environment respectively. Conclusion： Glass-infiltrated alumina-based dental ceramics have pronounced SCG. The subcritical crack growth velocity of wet specimens is speeded at same stress intensity factor of dry specimens, which implies that wet environment speeds up the subcritical crack growth.

关 键 词：牙科陶瓷 环境 循环疲劳 亚临界裂纹扩展 

分 类 号：R783.1[医药卫生—口腔医学]