Creep behaviour of novel dense fused mullite containing Ti 2 O 3 smelter from abandoned bauxite

Abstract

This work evaluated the creep behaviour of novel dense fused mullite containing Ti₂O₃ smelter from abandoned bauxite at different temperatures. The creep test was held at 0.2 MPa for 50 h in an air atmosphere at 1350 °C, 1400 °C, 1450 °C and 1500 °C. XRD, SEM, and industrial CT were used to analyze the phase composition, microstructure, and pore distribution of the samples after creep test. The results show that the fused mullite containing Ti₂O₃ has excellent volume stability. This is attributed to the morphology of mullite gradually changing from a dense form to its classical elongated columnar form with the change of the titanium endowment state, which confers excellent creep resistance. In the exterior of the samples, Ti₂O₃ gradually transformed into TiO₂ and Al₂TiO₅, and Ti⁴⁺ contributed to the development of the mullite's columnar morphology. In the interior of the samples, the inhibitory effect of Ti³⁺ on the growth and development of mullite disappeared with the transformation of Ti₂O₃ to Ti₃O₅. Fused mullite was also gradually transformed into a long columnar morphology. The pore evolution process of the creep samples characterized by industrial CT was consistent with the above creep conclusions. The creep mechanism model is based on the effect of the reaction of Ti₂O₃ and the morphological evolution of fused mullite on the creep behaviour at different temperatures.