Phase transformation and sustained load crack growth in ZrO2 + 3 mol% Y2O3: Experiments and kinetic modeling

R-curve behaviour of 2Y-TZP with submicron grain size

“…As a rising R-curve could not be obtained with measurements in air, crack extension in the vacuum of a field emission scanning electron microscope (FESEM) was also quantified. These data are particularly pertinent as Y-TZP is known to be very susceptible to subcritical crack growth, [29][30][31] which leads to a velocity dependence of the R-curve 32 in air for materials toughened by process zone mechanisms. To rationalize the toughening mechanism, transformation zone profiles were obtained using Raman microscopy.…”

Subcritical Crack Propagation in 3Y‐TZP Ceramics: Static and Cyclic Fatigue

“…16 Therefore, for most measurements where the crack length exceeds a few tens of micrometers, the toughness can be considered to be constant, which simplifies the crack-propagation analysis and makes 3Y-TZP ceramics excellent candidates for crack-propagation studies. The subcritical crack growth of 3Y-TZP has been investigated by Knechtel et al, 17 Chevalier et al, 18 Alcala and Anglada, 19 and Yin et al 20 In all cases, the experimental results, although conducted on different materials, were in fair agreement and the crack propagation was attributed to the presence of H 2 O. Although the role of H 2 O seems to be clear, different mechanisms-including stress corrosion 17,18 and zirconia destabilization at the crack tip 20 -have been proposed to explain this slow-crack-growth phenomenon.…”

Fatigue and Static Crack Propagation in Yttria‐Stabilized Tetragonal Zirconia Polycrystals: Crack Growth Micromechanisms and Precracking Effects

“…In this sense, although cracktip shielding is expected to restrain crack propagation, the increase in monoclinic content at the crack tip due to t → m transformation may embrittle the material and enhance environmental interactions at the crack-tip region. 26 Stable crack growth is generally correlated with the value of the effective stress intensity factor at the crack tip, K t , which is given by § The influence of the environment in the crack growth behavior of the material was confirmed here by measuring crack propagation with indentation cracks in air and oil environments. The results clearly showed that the post-indentation crack growth that was detected in air was larger than that which was monitored with oil-protected indentation cracks.…”

“…This aspect is particularly relevant in Y-TZP because this material is strongly susceptible to exhibit static crack growth effects. 4,26 In this regard, a key issue in the comparison of static and fatigue crack growth micromechanisms may lie in the fractographic observation of striation-like features that have been reported in previous studies on fatigue crack propagation in Y-TZP. 19,27 Such salient fractographic features are especially appealing because little or no indication of fatigue crack propagation is usually found from observations of the fracture surfaces of ceramic materials.…”