CRYSTALLOGRAPHIC ANALYSIS OF THE MONOCLINIC HERRINGBONE STRUCTURE IN AN ARC-MELTED ZRO2-2MOL-PERCENT Y2O3 ALLOY

A herringbone structure of the m-phase developed during low temperature aging of an arc-melted ZrO2-2 mol% Y2O3 alloy. An electron microscopic study revealed that the structure comprised four variants, which shared a common cm axis and were nearly twin related with one another across the (100)m and (110)m interfaces. A growth mechanism was proposed based on the present observation and previously obtained phenomenological solutions for an initially isolated thin plate. The mechanism suggested that a particular mode of interaction of growing plates at the (110)t band boundaries of the parent herringbone structure was responsible to the formation of the m-phase herringbone structure. The overall distortion of the resulting structure was found to be a nearly uniaxial elongation along the specimen surface; such a distortion could be easily accomodated when the transformation took place on a specimen surface, as in the present case. © 1990.