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Crack Formation and Shape of Fracture Surface in Tabular-Alumina-Based Castables with Addition of Specific Aggregates
J. Schnieder, L. Lynen, N. Traon, T. Tonnesen, R. Telle
RWTH Aachen University, Institute of Mineral Engineering, Templergraben 55, 52062 Aachen, Germany
received November 08, 2013, received in revised form January 17, 2014, accepted March 13, 2014
Vol. 5, No. 2, Pages 131-136 DOI: 10.4416/JCST2013-00039
Abstract
Understanding the mechanical fracture and the microstructural behavior of refractories subject to thermal shock treatment is fundamental for the design of high-performance refractory materials. In recent decades, understanding has been focused on mechanisms occurring at the crack tip, namely in advanced ceramics. The focus recently switched to phenomena occurring in a different process zone of the crack, the wake region or following process zone. To understand the mechanisms in this wake region, specific aggregates are used in a model castable formulation based on tabular alumina, namely eutectic aggregates composed of Al2O3-ZrO2-SiO2 and Al2O3-ZrO2. The influence of these aggregates on the elastic and thermo-mechanical properties as well as on the crack path and the fracture surface is examined. This survey will put emphasis on the impact of each aggregate on the fracture surface and the crack path after the model castable has undergone several thermal shock cycles.
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Keywords
Refractories, microstructure analysis, eutectic aggregates, thermal shock
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