Microcracking in Large-grain Al2O3

Elastic properties and microstructure: study of two fused cast refractory materials

“…Moreover, the curve globally describes a hysteresis loop which is characteristic of a closure-opening mechanism of microcracks, on heating and cooling coarse grained materials. 5 In the present case, the creation of cracks occurs during the manufacturing of the products because of internal stresses developed when cooling. These cracks are then healed at the first heating-up.…”

Thermal properties of a reaction hot pressed Mo≤5Si3C≤1 ceramic

“…This calculation assumed a DT of 1300 C (stresses set at the ductile to brittle transition at w1300 C) and an elastic modulus of 301 GPa [1]. In other materials, such as Al 2 O 3 and TiO 2 , large thermal stress due to anisotropic CTEs caused microcracking [12][13][14] similar to those observed for this material in Fig. 2.…”

Experimental and numerical study of the thermomechanical behaviour of refractory model materials

“…However, because of their coarse grains, heterogeneous and multiscaled structure, refractories exhibit behaviours far from this prediction and, indeed, research works rather report an hysteresis loop shape for Young's modulus variations versus temperature. For example, Case et al 6 have observed hysteresis phenomena on anisotropic coarse grained alumina material and Nonnet et al 7 so as Baudson et al 8 have underlined similar behaviours for alumina castables and MgO/C refractories. These discrepancies, with the predictions given by the model of Wachtman et al 5 are not always due to the same physical mechanisms.…”