Strength and Microstructure in Lithium Disilicate Glass‐Ceramics

The effect of heat treatment on the microstructure of Li 2 O‐Al 2 O 3 ·SiO 2 glass‐ceramics which contain crystals of either Li 2 SiO 3 , Li 2 Si 2 O 5 , or both was investigated quantitatively. Strength determinations for abraded rods were correlated with heat treatment on the basis of both size and distribution of crystals and the type and amount of crystal phases present. The presence of Li 2 Si 2 O 5 crystals enhanced the strength, whereas the presence of Li 2 SiO 3 crystals did not change the strength of the abraded parent glass. The interrelation between strength and microstructure is discussed.