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Study on failure mechanism of high-temperature refractory ceramics

Abstract:

Refractories are the coarse ceramics used at high temperature, which has intrinsic quasi-brittle mechanical behavior. During their application, the refractory ceramics sustain considerable stain caused by thermal shock and mechanical loading, which challenge the serve performance and longevity. This talk will address some research progresses concerning the investigation of thermo-mechanical behaviour and relevant concepts of material development, including: (i) theoretical basis and methods establishment; (ii) cases study on the failure mechanism of varied refractory ceramics; (iii) development of advanced numerical material models. Namely, a series of methods is validated and developed for studying the thermo-mechanical of refractories under different service conditions, such as the symmetric/asymmetric wedge splitting test, nonstandard high T/P creep test, modified tensile test as well as their combined application with in-situ damage evaluation techniques, i.e. digital image correlation, acoustic emission and so on. These methods are used to clarify the distinguished failure mechanism for typical refractories and structures, which could be related to the localized thermal mismatch, phase transformation, addition of second “flexible” phases and dense aggregate lightweighting. The results favor the understanding as well as the improvement of materials. Finally, the multi-scale FE simulation strategy with continuum heterogeneous material model is proposed. By the experimental and modelling methods, the relationship between the macro-scale mechanical properties and the micro-scale failure processes is revealed. More details in the talk!