Statistical fatigue strength evaluation and inelastic deformation generated during static and cyclic loadings in Ce-TZP/alumina nanocomposite: part 2 – in water environment

Phase transformation induced fatigue of a Ce‐TZP/Al2O3 composite

“…As the maximum loading stress was 370 MPa, the specimens exhibited no failure at 10 6 cycles. This value is lower than the values reported in previous studies [9][10][11][12][13] One of the reasons can be related to the use of an annealing treatment; another one to the fact that the grain size of our specimens is larger. A coarser microstructure would lower the initial bending strength and fatigue strength.…”

“…Though the fatigue strength obtained in the present study was lower, the ratio of fatigue strength to initial bending strength was 0.76, which falled within the range from 0.84 to 0.67 as reported in the previous studies. [9][10][11][12][13] It implies that the fatigue strength might be estimated by knowing the initial bending strength. If it is the case, this value of ratio exhibits certain technological significance; namely, it provides an estimate on fatigue strength without measuring the S-N curve.…”

“…The 4-point bending technique was frequently used to determine the S-N curve of TZPs and their composites. 9,10,12,13 During bending, the tensile stress was the largest on the tensile surface, 30 then reduced its magnitude toward the mid-plane of the testing bar. Eventually, it changed to compressive stress to the opposite surface.…”

“…11 For one of their Y-TZPs, the fatigue strength was approximately 80% of initial bending strength. Ueno et al 12 and Nawa et al 13 measured the fatigue resistance of Y-TZP and Ce-TZP/Al 2 O 3 composite either in air or in water. These studies suggested that the fatigue strength of TZP and TZP/Al 2 O 3 composites were slightly greater than 70% of their initial bending strength.…”

“…The fatigue failure of ceramics was usually a brittle type 9–13 . The failure generally initiated either from microcrack (induced by phase transformation) 14 or from pre‐existed flaw (processing‐related) 11 .…”