Slow crack growth behavior of 3Y-TZP in cryogenic environment using dynamic fatigue and indentation technique

The dynamic fatigue of 3 mol% Y2O3 stabilized tetragonal zirconia ceramic (3Y-TZP) was assessed at 293 K and 77 K by testing the same batch of specimens in four-point flexure at various stress rates. The crack propagation velocities were also measured using Vickers indentation specimens under dynamic-loading conditions in ambient and cryogenic environnient. The slow crack growth (SCG) parameter n at 77 K was larger than that at 293 K. Also, the crack propagation velocity under cryogenic circumstance is much slower than that under ambient circumstance. The experimental results suggest that the 3Y-TZP exhibits a lesser degree of SCG behavior in cryogenic environment. It should be ascribed to two reasons. The negligible effect of stress corrosion and crack tip shielding mechanism induced by temperature. The high SCG resistance in cryogenic environment makes the 3Y-TZP a promising candidate material for long-term service in cryogenic structural applications. (C) 2015 Elsevier B.V. All rights reserved.