Mechanical Properties of Mica Glass‐Ceramics

The mechanical properties of fluorophlogopite mica‐based glass‐ceramics, such as fracture toughness, flexural strength, and machinability, were investigated. It has been shown that toughening increments in the glass‐ceramics occurred by crack deflection and branching by crystals with a high aspect ratio. All the glass‐ceramics heat treated at 1000°–1150°C exhibited a higher fracture toughness of 1.2–2.2 MPa‐m 1/2 as compared to 0.8 MPa‐m 1/2 for the parent glass, and showed average flexural strengths of 140–160 MPa. It has been suggested that ( H/K Ic ) 2 of the mica glass‐ceramic be used to estimate the machinability, because it decreases linearly with machinability.