Temperature dependence of the elastic moduli, dilational and shear internal frictions and acoustic wave velocity for alumina, (Y)TZP and β′-sialon ceramics

Abstract

Young's, shear and bulk moduli, Poisson's ratio and Lame parameters, longitudinal and transverse internal friction values and acoustic wave velocity anisotropy factors for three kinds of polycrystalline compounds, α-alumina, yttria-stabilized tetragonal zirconia polycrystal, (Y)TZP, and β′-sialon, (Si,Al)3(N, O)4, were simultaneously measured over a temperature range 295–1773 K, by an ultrasonic pulse sing-around method. These elastic moduli and Lame parameters decreases and Poisson's ratio increases with increasing temperature, suggesting activation of a shear mode in the high-temperature region. The high-temperature shear internal friction for (Y)TZP and sialon were more sensitive to relief of strain and softening of glassy phase at grain boundaries, respectively, compared with the dilational friction.