Fracture toughness and subcritical crack growth analysis of high-translucent zirconia prepared by stereolithography-based additive manufacturing.

Abstract

The objective was to study the subcritical crack growth phenomena and determine the fracture toughness of two yttria-partially-stabilized zirconia ceramics. One of the two materials evaluated was a commercially available 5 mol% yttria partially stabilized zirconia (5Y-PSZ), and the other was an experimental partially stabilized zirconia made from a mixture of 3 mol% and 8 mol% yttria stabilized zirconia powder (3Y+8Y-PSZ), with the final samples prepared by the Stereolithography (SLA) process. The samples in water were tested by three-point bending experiments at different stress rates to obtain Weibull and SCG parameters. The results show that 3Y+8Y-PSZ has higher Weibull modulus(m = 11.54) and characteristic strength(σ₀ = 812.27 MPa) compared to 5Y-PSZ (m = 8.57, σ₀ = 647.25 MPa). SCG parameters n obtained for 5Y-PSZ and 3Y+8Y-PSZ tested in water were 26.03, 37.94, respectively. The strength of 5Y-PSZ and 3Y+8Y-PSZ (P_f = 5%) was reduced by 56.49%, 45.30% after 10 years of simulated use. Regarding the fracture toughness of both materials, 3Y+8Y-PSZ had higher values regardless of the method used to determine it. However, the fitting correction factor of the Vickers indentation method was not applicable to either 5Y-PSZ or 3Y+8Y-PSZ. Determining the SCG parameters of two materials and predicting their lifetimes using constant stress rate testing is an effective way to evaluate materials.