On the different behaviour of porous ceramic polycrystalline materials under tension and compression stress state

Abstract

The aim of the chapter is to present different response of porous polycrystalline ceramic materials under tension and compression stress states. The main attention of this chapter is on the description of porous aluminum oxide (AI2O3), which is subjected to two different stress states, including uniaxial tension and uniaxial compression. In both stress states (tension and compression), the proposed model describes the gradual changes of elastic mechanical features because of initiation of cracks from stress concentration at the boundary of pores and crack growthbecause of. Porosity of the material is distributed inside grains and along grain boundaries. In ceramic polycrystalline, material cracks grow mainly intergranularly because of less value of the fracture surface energy of grain boundary compared to grain. The theoretical modeling of the material is done by mesomechanical approach with the application of average procedure over the representative surface element (RSE) and considering initial porosity and a set of growing cracks. It allows building constitutive relations to get comparison of the material behavior under tension and compression.