氟金云母微晶玻璃陶瓷的动态本构关系及断裂机理研究

STUDY ON THE DYNAMIC CONSTITUTIVE RELATIONSHIP AND FRACTURE MECHANISM OF FLUOROPHLOGOPITE GLASS-CERAMICS

为了研究氟金云母微晶玻璃陶瓷的动态力学性能及断裂机理,利用高速液压伺服材料试验机进行了动态压缩实验,得到试样中等应变速率下的动态力学参数,结果表明该陶瓷材料具有明显的应变率效应,并基于损伤力学理论,得到了该材料的弹脆性动态损伤本构方程。通过对试样断口微观形貌的SEM观测,并结合纳米压痕实验,分析了材料的断裂机理。从试样断口的宏观和微观形貌可得:材料断裂方式为脆性解理断裂,云母相与玻璃相交界面存在大量沿晶微裂纹;由纳米压痕实验验证了两相之间弱界面的存在,微裂纹最早成核于两相交界处,并沿弱界面扩展,成核载荷为20 mN。

In order to study the dynamic mechanical properties and fracture mechanism of fluorophlogopite glass-ceramics, a dynamic compression test was carried out with a high-speed hydraulic servo testing machine, and the dynamic mechanical parameters of samples at medium strain rate were obtained. The results show that the ceramic material has an obvious strain rate effect. Based on damage mechanics theory, the dynamic damage constitutive equation of elastic brittleness is obtained. The fracture mechanism is analyzed by SEM observation of the samples fracture microstructure and nano-indentation tests. The fracture macroscopic and microcosmic morphology of samples show that the material fracture mode is of brittle cleavage fracture, and there are lots of microcracks at the interface between a mica phase and glass. The nano-indentation test verifies the existence of the weak interface between two phases. The microcracks are first nucleate at the junction of two phases and extend along the weak interface, and the nucleation load is 20 mN.