Investigation of Indentation Fracture Toughness (KIC) and Weibull Parameters of 0.25Li2O.2SiO2-0.75BaO.2SiO2 Glass-Ceramic

Abstract

In the present study, mechanical properties of 0.25Li 2 O.2SiO 2 -0.75BaO.2SiO 2 glass-ceramic were investigated. The transformations' temperatures were determined by DTA instrument. The optimum nucleation temperature was found to be 540°C. This suggested the crystallization temperatures as 675, 720 and 800°C. After carrying out crystallization heat treatments, Vickers indentation test was applied. In order to determine the indentation fracture toughness (K IC ), crack half-length ‚c' of the samples was measured. To calculate K IC , Young's modulus, E and the measured hardness, H v were used. Using K IC and probability of fracture ‚P', ln ln[1/(1 -P)] -ln K IC graph was drawn based on the Weibull distribution equation. Consequently, Weibull modulus, ‚m' and scale parameter, ‚K 0 ' were determined and compared with each other.