Fracture toughness measurement in fused quartz using triangular chevron-notched micro-cantilevers

We extend to flat surfaces the fracture toughness method presented in Acta Materialia vol. 86 (2015) p. 385 and measure in this manner the fracture toughness of fused quartz. Tests give 0.67 ± 0.01 MPa m1/2, which agrees with earlier microscopic and macroscopic test data for the fast fracture toughness of this material. Data show no signs of sub-critical crack growth; this observation is at variance with what one would expect from literature data on the phenomenon.