Evaluation of fracture behavior of lightweight magnesia-based refractories via wedge splitting test along with acoustic emission detection |
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Authors: | Junjie Yan Wen Yan Yajie Dai Guangqiang Li Xiao Wang Yucheng Yin |
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Affiliation: | 1. The State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan, China;2. School of Chemical Engineering, Qinghai University, Xining, China |
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Abstract: | The effect of spinel powder on the fracture behavior and mechanical properties of lightweight magnesia-based refractories containing microporous magnesia aggregates with high apparent porosity (37.4%) were investigated by the wedge splitting test (WST) with the digital image correlation and acoustic emission. With the addition of spinel powder, lightweight magnesia spinel refractories showed a higher cold compressive strength compared with lightweight pure magnesia refractories. From the WST, the addition of spinel powder increased the specific fracture energy and characteristic length of lightweight magnesia spinel refractories, which improved the crack propagation resistance. The increased tortuosity of main crack and a higher ratio of crack propagation along the aggregates/matrix interface were main reasons for reducing the brittleness of lightweight magnesia spinel refractories. Besides, acoustic emission (AE) signal activity indicated that the propagation of pregenerated micro-cracks by the thermal mismatch and the development of fracture progress zone were primary ways to consume energy in lightweight magnesia spinel refractories. The reduced proportion of crack propagation within aggregates was also detected by the peak frequency of AE signals in lightweight magnesia spinel refractories. For microporous magnesia aggregates with high apparent porosity (37.4%), lightweight magnesia spinel refractories also showed reduced brittleness fracture behavior than lightweight pure magnesia refractories. |
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Keywords: | acoustic emission digital image correlation fracture behavior lightweight magnesia-based refractories |
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