Viscoelastic Properties of Ni-TZP Composite

摘要

A mechanical spectroscopy study has been made on fine-grained Ni-TZP(ZrO_2-3 mol.percentY_2O_3) composite in an attempt toassess the following micromechanical prediction. A dual-phase material withfine-grained constituents deforming by Coble-type boundary-diffusion creepexhibits viscoelastic (anelastic plus viscous) behavior. A composite with 10vol.percentTZP, fabricated by powder processing is examined. DynamicYoung's modulus, E_(#omega#) and internal friction, tan_(#PHI#), aremeasured over a temperature range of 25 to 800deg C at frequencies of 0.01,0.05 and 0.1 Hz using a specially designed tension-compression apparatus.The data obtained are analyzed in terms of loss compliance, J_2 tan(#PHI#)/E_(#omega#). Two relaxation peaks are observed in the composite.An exponential involved in the peak and background components aredetermined and, by making a further analysis based on the micromechanicalformulation and also taking the well-known relaxation due to viscous grain-boundary sliding into account, the implications of these quantities arediscussed in terms of constituent material parameters(boundary diffusivity,grain size, etc.).