SiC_f/TC17 复合材料拉伸性能研究及叶环结构强度分析

Longitudinal tensile tests were carried out on SiC_f/TC17 composites at room/high temperature to investigate the tensile behaviors. The damage evolution and failure mechanisms were revealed based on microscopic fracture morphology analysis. Afterwards， a constitutive model was developed to describe the tensile behaviors of SiC_f/TC17 composites. The results showed that the ultimate tensile strength of SiC_f/TC17 composites decreased with the increasing temperature， while the nonlinear segment of the stress-strain curve increased. The major failure mechanisms at room temperature lied in multiple fractures of the interfacial reaction layer and random breakage of weak fibers，whereas large-scale interface debonding and fiber pullout， matrix cracking and fiber breakage were more common at high temperatures. The results of different strength-predicted models demonstrated that the failure mode of SiC_f/TC17 composites at room temperature was controlled by local loading sharing， while the high-temperature ultimate tensile strength was more consistent with the global loading sharing model. The stress-strain curve of SiC_f/TC17 composites was simulated by the proposed constitutive model with coupling fiber cumulative damage. The simulation results exhibited a trend similar to that of the experimental data at 25 ℃ and 450 ℃. Finally， based on the tensile properties obtained from the tests， finite element stress-strain analysis and static strength calibration of the TMCs blade-ring structure were carried out. The result indicated that the blade-ring structure exhibited a significantly elevated strength reserve factor at the typical service temperature.