Fracture Toughness and Spalling Behavior of High-Al2O3 Refractories |
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Authors: | D R LARSON J A COPPOLA D P H HASSELMAN R C BRADT |
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Affiliation: | Ceramics Research Laboratory, Materials Research Center, Lehigh University, Bethlehem, Pennsylvania 18015;Ceramic Science Section, The Pennsylvania State University, University Park, Pennsylvania 16802 |
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Abstract: | The fracture energies and spalling resistance of high-Al2O3 refractories were studied. The fracture energies, γ WOF and γ NBT , were measured by the work-of-fracture and the notched-beam-test methods, respectively. Spalling resistance, as measured by the relative strength retained in a water quench, correlated well with the thermal-stress resistance parameter applicable to stable crack propagation under conditions of thermal shock, (γ WOF /α2 E 0). Many of the refractories exhibited high ratios of γWOF to γNBT; such high ratios were shown analytically to maximize the parameter ( R 1111= E 0γWOF/S12) which describes the resistance to catastrophic spalling. The increase of crack length with increasing quenching temperature difference (Δ T ) was somewhat less than that predicted theoretically; the discrepancy was attributed to an increase of crack density with Δ T . In general, the results show that fracture energy is important in establishing the spalling resistance of high-Al2O3 refractories. |
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