Neutron diffraction measurements of residual stress distribution in large zirconia based refractory bricks produced by electro-fusion and casting

Abstract Electro-fusion and casting is used to produce large refractory bricks (∼250 kg) containing a high amount of ZrO 2 . These bricks are used in glass-making furnaces where good mechanical performance is required at very high temperatures (>1500 °C). During the manufacturing procedure, they develop large residual stresses as a result of the cooling conditions and structural phase transformations they underwent. This leads to stress concentration and crack formation at different length scales. In order to characterize these phenomena, a ‘multi-scale’ analysis approach is under development, where different internal strain measurement methods are combined. In this approach we benefit from different gauge volumes provided by various diffraction methods, ranging from a few hundred nanometres to a few tens of millimetres. In the present paper, the results of neutron diffraction measurements on large ZrO 2 blocks are given. These results show the level of internal strains at the millimetre scale, based on ( 3 ¯ 11 ) reflection of the monoclinic ZrO 2 . Overall, a range of 0.025% tensile to 0.1% compressive strain was observed. Clear strain gradients were also visible, as larger values in the interior of the block were encountered.