High temperature mechanical behavior of low stiffness Al ₂ TiO ₅ and Al ₂ TiO ₅ –3Al ₂ O ₃ .2SiO ₂ –ZrTiO ₄ composite materials

Abstract The mechanical behavior of low (and negative) thermal expansion and low stiffness Al ₂ TiO ₅ materials and Al ₂ TiO ₅ –3Al ₂ O ₃ .2SiO ₂ –ZrTiO ₄ 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 ( E _app ) and mechanical strength ( σ _F ) were determined. Fracture mechanisms and fracture patterns were also analyzed. All materials showed a brittle behavior up to 800°C. The thermal variation of σ _F , that was even higher as testing temperature increased, was interpreted based on the microcracks behavior. A double linear correlation of E _app 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.