Mechanical properties of a transformation-toughened glass-ceramic

The fracture toughness of a transformation-toughened glass-ceramic containing 12 vol % t-ZrO2 was measured. Heat-treatment conditions were selected to produce from the same glass composition a glass-ceramic which contained 12 vol % m-ZrO2 in a nearly identical matrix. The transformation-toughened material had a fracture toughness 65% greater than the m-ZrO2-containing material at room temperature. At 77 K both materials had approximately the same fracture toughness. The susceptibility of the two glass-ceramics to fatigue was determined. No improvement in fatigue behaviour of the transformation-toughened glass-ceramic over the other glass-ceramic was observed. 29 refs.