Flexural Stress Homogenization Effects of Interfacial Transition Layers in Modified ZrB₂-Al₂O₃/Epoxy Composites

Abstract

The effect of interfacial modification on flexural strength of epoxy composites filled with modified ZrB₂-Al₂O₃ composite fillers was investigated in order to explore the stress distribution of modified composites under external load. The mechanical performance of epoxy composites filled with 0 vol%, 1 vol%, 3 vol% and 5 vol% unmodified and modified ZrB₂-Al₂O₃ fillers was characterized by three point bending (TPB) tests. The fracture surfaces of epoxy composites were observed by scanning electronic microscope (SEM). The results showed that the epoxy composite reinforced by 1 vol% modified fillers exhibited the optimal mechanical performance. According to the Von Mises stress contours simulated by finite element models (FEM) and the SEM images, it was shown that the modified ZrB₂-Al₂O₃ multiphase fillers could homogenize the stress in the epoxy composites due to the transition effect resulted from the interfacial modification layers on the surfaces of multiphase fillers. It contributed to the improvement of mechanical performance of epoxy composites further.

Keywords

surface modification / stress transfer / polymer-matrix composites (PMCs) / finite element analysis (FEA)