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.

Role of Oxygen in Vacancy-Induced Phase Formation and Crystallization of Al2TiO5-Based Chemical Vapor-Deposited Coatings

“…Notably, the limited thermal stability of Al 2 TiO 5 at intermediate temperatures ( e.g. , 800–1300 °C) , currently hampers the phase’s practical applicability, thus creating incentives to improve its thermal stability further.…”