High temperature mechanical behavior of low stiffness Al2TiO5 and Al2TiO5–3Al2O3.2SiO2–ZrTiO4 composite materials

Abstract

The mechanical behavior of low (and negative) thermal expansion and low stiffness Al2TiO5 materials and Al2TiO5–3Al2O3.2SiO2–ZrTiO4 composite materials was studied by diametral compression test at room temperature 400 and 800°C. The effect of both temperature and composition was analyzed. Stress–strain curves were obtained and, from them, apparent elastic modulus (Eapp) and mechanical strength (σF) were determined. Fracture mechanisms and fracture patterns were also analyzed. All materials showed a brittle behavior up to 800°C. The thermal variation of σF, that was even higher as testing temperature increased, was interpreted based on the microcracks behavior. A double linear correlation of Eapp was found with temperature (T) and zircon content ([Z]), with a fitting coefficient >.9. The particular low stiffness and the mechanical and thermal behavior of the studied materials suggest that they would be able to withstand thermal stresses.