Mechanical Property and Fracture Behavior of BaTiO3-Based Nanocomposites

Dense and fine grained BaTiO₃-based composites with the nano-sized SiC particulate were successfully fabricated by hot-pressing method. Mechanical properties and fracture behavior were investigated. High resolution TEM observation revealed that there were no conspicuous reaction phases in the interface between BaTiO₃ and SiC. The crystal structure was changed from ferroelectric tetragonal to paraelectric cubic phase with increasing SiC, and finally was pseudo-cubic for BaTiO₃ with more than 3vol% SiC. Mechanical properties such as fracture strength, fracture toughness, Young's modulus and so on were markedly improved by the incorporation of nano-sized SiC particulates. The improvement of mechanical properties, particularly, microhardness and Young's modulus might be caused by the crystal structural change as well as SiC addition. Fracture behavior and subcritical crack growth (SCG) phenomenon were also investigated using the indentation induced flaw method (IIF).