Spontaneous Ejecta from β-Eucryptite Composites

Polycrystalline ceramic composites, comprised of primarily β‐eucryptite (LiAlSiO4) and lithium aluminate (LiAl5O8) crystals, with a near‐zero coefficient of thermal expansion, were examined with indentation experiments. A unique behavior is reported: subsequent to the indentation, the material responds by ejecting multiple particles violently from the area of the indent for a time period up to several minutes. The behavior is suppressed in the absence of moisture. An estimate of the source of energy for this process and a potential mechanism are discussed.