(The) relation between ultrasonic attenuation, acoustic emission response and hardness in BOS-1 glass ceramic

Abstract

The density and percentage crystallinity of glass ceramic (BOS-1 System) was increased with heat treatment time and the crystalline phase was identified as alumina diopside. Ultrasonic attenuation measurement with 5MHz longitudinal wave showed exponential dependence on the percentage crystallinity, then acoustic emission response in total counts during hardness indentation varied exponential dependence on $(Hv)^{\frac{1}{2}}$. The variation would be caused by interdependence between the work done by the indentor and the diagonal of indentation. Ultrasonic attenuation, $\alpha$ in Nepers/cm, and acoustic emission response, $\Sigma N$ in total counts, in glass ceramic is expressed as $$(\ln\, g(\Sigma N))^2\,(\ln\,h\alpha) = K$$ where constants g, h and k are 7259, 7.92 and 234, respectively. This implies that when the source energy during indentation is released through its medium, acoustic emission response is determined by ultrasonic attenuation which controlled by the energy loss propagating through medium.