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目的:研究牙科美学陶瓷(IPS-Empress 2)的层状复合结构亚临界裂纹(以下简称SCG)扩展情况。方法:采用Weibull法分析由三点弯曲强度测量方法(3p)获得15个IPS-Empress 2的复层结构样本的弯曲强度数据和由循环疲劳测试(F)获得的15个IPS-Empress 2的复层结构样本循环疲劳断裂次数数据;通过帕里斯定律分析试件在Hertzian循环加载后的亚临界裂纹扩展情况,SCG行为通过裂纹扩展速度和应力强度因子(K1)的函数关系来描述。结果:通过Weibull法得到IPS-Empress 2的复层结构的Weibull模数为7.7。IPS-Empress 2复层结构在循环载荷下发生亚临界裂纹扩展后导致材料断裂,在应力强度因子K1为临界应力因子KIC的52%时发生裂纹传播。结论:牙科陶瓷层状复合结构循环载荷下存在亚临界裂纹扩展。
Objective: To study the subcritical crack propagation (hereinafter referred to as SCG) of layered composites of dental aesthetic ceramics (IPS-Empress 2). Methods: Weibull method was used to analyze the bending strength data of 15 IPS-Empress 2 specimens from three-point bending strength measurement (3p) and 15 IPS-Empress 2 from cyclic fatigue test (F) The data of cyclic fatigue fracture number in the layered structure samples were analyzed. The subcritical crack propagation was analyzed by Paris’s law after Hertzian cycle loading. The behavior of SCG was described by the function of crack propagation velocity and stress intensity factor (K1). Results: The Weibull modulus of the composite of IPS-Empress 2 obtained by Weibull method was 7.7. The fracture of the IPS-Empress 2 multi-layer structure caused by the subcritical crack propagation under cyclic loading led to the crack propagation. Crack propagation occurred when the stress intensity factor K1 was 52% of the critical stress factor KIC. Conclusion: There exists subcritical crack propagation under the cyclic loading of dental ceramic layered composite structures.