Meini Yuan

Effect of properties of SiC fibers on longitudinal tensile behavior of SiCf/Ti-6Al-4V composites

Three types of SiC fibers with different tensile strength were employed to prepare unidirectional titanium matrix composites. The strengths of the original SiC fibers and extracted fibers from the composites were measured. The results show that the mechanical properties of fibers are greatly damaged by the consolidation processing of the composite. The strength data of the extracted fibers are used to predict the strength of the composites according to two theoretic models. The Globe Load-Sharing(GLS) model overestimates the strength of the composites. If the Local Load-Sharing(LLS) model assumes that failure occurs after the formation of a cluster with three broken fibers, the model can predict the strength of the composites exactly.

Evaluation of interface fracture toughness in SiC fiber reinforced titanium matrix composite

The finite element method based on the equivalent domain integral technique was developed to simulate the push out test and evaluate the interfacial fracture toughness of SiC reinforced titanium matrix composites. A special subroutine was introduced while modeling the push-out test to control interfacial failure process. In addition, the residual stresses, Poisson ratio and friction stresses were all considered in the finite element analysis and the interface debonding was described as a continuous process. The results show that the interfacial fracture toughness of SiC/Timetal-834 is about 50 J/m2. Moreover, the effects of various parameters on the interfacial fracture toughness and the variations of energy release rates at both ends of the specimen were analyzed in detail.