Table of Contents
Journal of Ceramics
Volume 2014 (2014), Article ID 169748, 9 pages
http://dx.doi.org/10.1155/2014/169748
Research Article

Modeling of Thermal and Mechanical Behavior of ZrB2-SiC Ceramics after High Temperature Oxidation

1Department of Mechanical and Aerospace Engineering, Missouri University of Science and Technology, Rolla, MO 65409-0050, USA
2Department of Materials Science and Engineering, Missouri University of Science and Technology, Rolla, MO 65409-0340, USA

Received 31 July 2014; Accepted 18 October 2014; Published 11 November 2014

Academic Editor: Guillaume Bernard-Granger

Copyright © 2014 Jun Wei et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The effects of oxidation on heat transfer and mechanical behavior of ZrB2-SiC ceramics at high temperature are modeled using a micromechanics based finite element model. The model recognizes that when exposed to high temperature in air ZrB2-SiC oxidizes into ZrO2, SiO2, and SiC-depleted ZrB2 layer. A steady-state heat transfer analysis was conducted at first and that is followed by a thermal stress analysis. A “global-local modeling” technique is used combining finite element with infinite element for thermal stress analysis. A theoretical formulation is developed for calculating the thermal conductivity of liquid phase SiO2. All other temperature dependent thermal and mechanical properties were obtained from published literature. Thermal stress concentrations occur near the pore due to the geometric discontinuity and material properties mismatch between the ceramic matrix and the new products. The predicted results indicate the development of thermal stresses in the SiO2 and ZrO2 layers and high residual stresses in the SiC-depleted ZrB2 layer.