Enhanced high‐temperature indentation fracture toughness of zirconia ceramics via HfO2 doping.
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| Title: | Enhanced high‐temperature indentation fracture toughness of zirconia ceramics via HfO |
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| Authors: | Lv, Yi‐Hang1,2 (AUTHOR), Wang, Xin‐Gang2 (AUTHOR) xgwang@mail.sic.ac.cn, Wang, Xiao‐Fei2 (AUTHOR), Wang, Ming2 (AUTHOR), Xu, Jing‐Cheng1 (AUTHOR), Lv, Song‐Ze2 (AUTHOR), He, Tao2 (AUTHOR), Jiang, Dan‐Yu2 (AUTHOR) |
| Source: | Journal of the American Ceramic Society. Aug2025, Vol. 108 Issue 8, p1-10. 10p. |
| Subjects: | Vickers hardness, Fracture toughness, High temperatures, Solid solutions, Hardness |
| Abstract: | In this research, 3 mol% Y2O3‐stabilized ZrO2 (3YSZ) ceramics doped with varying HfO2 content (5–30 mol%; denoted as xH3YSZ) were fabricated via pressureless sintering at temperatures ranging from 1400°C to 1600°C. The phase compositions, microstructures, hardness, indentation fracture toughness (at both room and high temperatures) were systematically investigated for the first time. Results revealed that 3YSZ and HfO2 formed a tetragonal phase solid solution when the HfO2 content was ≤10 mol%. However, at HfO2 concentrations of 15 mol% or higher, the ceramics exhibited a mixture of tetragonal and monoclinic phases (t and m phase). The incorporation of HfO2 significantly enhanced the indentation fracture toughness at both room and elevated temperatures. The room‐temperature indentation fracture toughness of 10H3YSZ ceramics sintered at 1400°C and 1600°C reached 5.76 ± 0.24 MPa m1/2 and 6.11 ± 0.09 MPa m1/2, respectively, markedly higher than that of undoped 3YSZ ceramics (4.25–4.94 MPa m1/2). At high temperatures, the indentation fracture toughness of 10H3YSZ ceramics sintered at 1600°C was at least 1.4 times of 3YSZ ceramics at 200–800°C. The Vickers hardness of xH3YSZ ceramics decreased with sintering temperature. The Vickers hardness of 10H3YSZ was 12.0 ± 0.19 GPa at room temperature, which decreased to 3.13 ± 0.19 GPa at 800°C. The enhanced indentation fracture toughness was attributed to the reduced threshold for initiating the tetragonal‐to‐monoclinic (t → m) phase transformation in HfO2‐doped ceramics, which increased crack shielding due to a larger volume fraction of transformed grains. Additionally, crack deflection and blunting mechanisms, promoted by grain growth and the reduced high‐temperature hardness at a sintering temperature of 1600°C, further contributed to the improved toughness. [ABSTRACT FROM AUTHOR] |
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| Database: | Engineering Source |
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| Abstract: | In this research, 3 mol% Y2O3‐stabilized ZrO2 (3YSZ) ceramics doped with varying HfO2 content (5–30 mol%; denoted as xH3YSZ) were fabricated via pressureless sintering at temperatures ranging from 1400°C to 1600°C. The phase compositions, microstructures, hardness, indentation fracture toughness (at both room and high temperatures) were systematically investigated for the first time. Results revealed that 3YSZ and HfO2 formed a tetragonal phase solid solution when the HfO2 content was ≤10 mol%. However, at HfO2 concentrations of 15 mol% or higher, the ceramics exhibited a mixture of tetragonal and monoclinic phases (t and m phase). The incorporation of HfO2 significantly enhanced the indentation fracture toughness at both room and elevated temperatures. The room‐temperature indentation fracture toughness of 10H3YSZ ceramics sintered at 1400°C and 1600°C reached 5.76 ± 0.24 MPa m1/2 and 6.11 ± 0.09 MPa m1/2, respectively, markedly higher than that of undoped 3YSZ ceramics (4.25–4.94 MPa m1/2). At high temperatures, the indentation fracture toughness of 10H3YSZ ceramics sintered at 1600°C was at least 1.4 times of 3YSZ ceramics at 200–800°C. The Vickers hardness of xH3YSZ ceramics decreased with sintering temperature. The Vickers hardness of 10H3YSZ was 12.0 ± 0.19 GPa at room temperature, which decreased to 3.13 ± 0.19 GPa at 800°C. The enhanced indentation fracture toughness was attributed to the reduced threshold for initiating the tetragonal‐to‐monoclinic (t → m) phase transformation in HfO2‐doped ceramics, which increased crack shielding due to a larger volume fraction of transformed grains. Additionally, crack deflection and blunting mechanisms, promoted by grain growth and the reduced high‐temperature hardness at a sintering temperature of 1600°C, further contributed to the improved toughness. [ABSTRACT FROM AUTHOR] |
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| ISSN: | 00027820 |
| DOI: | 10.1111/jace.20569 |
