R-curve of La2O3 doped Zirconia Toughened Alumina Composites Prepared via Stereolithography based 3D Printing
In this study, we combined liquid precursor infiltration of high introduction amounts of bi-additives (20wt%) and stereolithography-based 3D printing to fabricate zirconia toughened alumina, and the infiltration systems consist of the four following systems Zr4+/La3+, Zr4+/Er3+, Zr4+/Gd3+, and Zr4+/Ce4+. The sample immersed with Zr4+/La3+ shows intense peaks of m-ZrO2 phase compared to the other samples while a new phase of flake-like LaAl11O18 occurs in the Zr4+/La3+ immersed sample, the existence of which could be confirmed by XRD and EDS. The fracture toughness of the Zr4+/Er3+, Zr4+/Gd3+, and Zr4+/Ce4+ samples remained basically unchanged versus the crack size, while the measured fracture toughness values for the Zr4+/La3+ system could be fitted as a rising R-curve behavior with the steady-state fracture toughness of 17.76 MPa·m1/2. The enormous enhancement of the toughness could be attributed to thermal expansion misfit and flake-like LaAl11O18 in the Zr4+/La3+ system. The effect of residual stresses on the fracture mode and thus the toughness is discussed on the basis of theoretical calculation and analysis. It is the first time a rising R-curve behavior is observed in the 3D printed ceramics. The shocking discovery provides a highly effective toughening way in 3D printing combined infiltration approach.
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Posted 16 Apr, 2020
R-curve of La2O3 doped Zirconia Toughened Alumina Composites Prepared via Stereolithography based 3D Printing
Posted 16 Apr, 2020
In this study, we combined liquid precursor infiltration of high introduction amounts of bi-additives (20wt%) and stereolithography-based 3D printing to fabricate zirconia toughened alumina, and the infiltration systems consist of the four following systems Zr4+/La3+, Zr4+/Er3+, Zr4+/Gd3+, and Zr4+/Ce4+. The sample immersed with Zr4+/La3+ shows intense peaks of m-ZrO2 phase compared to the other samples while a new phase of flake-like LaAl11O18 occurs in the Zr4+/La3+ immersed sample, the existence of which could be confirmed by XRD and EDS. The fracture toughness of the Zr4+/Er3+, Zr4+/Gd3+, and Zr4+/Ce4+ samples remained basically unchanged versus the crack size, while the measured fracture toughness values for the Zr4+/La3+ system could be fitted as a rising R-curve behavior with the steady-state fracture toughness of 17.76 MPa·m1/2. The enormous enhancement of the toughness could be attributed to thermal expansion misfit and flake-like LaAl11O18 in the Zr4+/La3+ system. The effect of residual stresses on the fracture mode and thus the toughness is discussed on the basis of theoretical calculation and analysis. It is the first time a rising R-curve behavior is observed in the 3D printed ceramics. The shocking discovery provides a highly effective toughening way in 3D printing combined infiltration approach.
Figure 1
Figure 2
Figure 3
Figure 4