氧化锆陶瓷的动态弯曲断裂行为

The dynamic three-point bending test of zirconia ceramics is carried out by using the split Hopkinson pressure bar (SHPB) device combined with a newly designed fixture. The fracture initiation time of the specimen is determined by the strain gauge and finite element simulation,and the bending strength of the specimen is calculated from a transmission bar signal. It is found that the fracture initiation time of the specimen matches well with the peak moment of the transmitted wave,so that the peak value of the transmitted wave can be used to determine the bending strength. The force equilibrium of the specimen during loading is verified by analyzing the experimental data. In addition,the accuracy of determined fracture initiation time is verified by high-speed photography. The results show that the bending strength of the specimen shows a positive correlation with the loading rate and the fracture initiation time of the specimen shows a negative correlation with the loading rate in the loading rate range of 85. 4-239. 7 TPa/ s. With the increase in loading rate,the failure mode of zirconia ceramic specimens changes from a mixture mode of transgranular fracture and intergranular fracture to a failure mode dominated by transgranular fracture.