TY - JOUR
T1 - Low-temperature superplasticity in nanocrystalline tetragonal zirconia polycrystal (TZP)
AU - Yoshida, Hidehiro
AU - Matsui, Koji
AU - Ikuhara, Yuichi
PY - 2012/5
Y1 - 2012/5
N2 - Nanocrystalline tetragonal ZrO 2 polycrystals (TZP) have been fabricated by the pressureless sintering of recently developed tetragonal ZrO 2 powder containing 5.69 mol% YO 1.5 and 0.60 mol% AlO 1.5. The average grain sizes were 160 nm in the TZP sintered at 1150°C for 10 h and 150 nm in the 0.25 mol% GeO 2-doped TZP sintered at 1100°C for 100 h. The TZP and Ge 4+-doped TZP-sintered bodies were essentially single-phase materials, and neither the amorphous layer nor the second-phase particle was observed along the grain boundary faces. High-resolution transmission electron microscopy (HRTEM), scanning transmission electron microscopy (STEM), and nanoprobe energy-dispersive X-ray spectrometer (EDS) measurements revealed that the Y 3+, Al 3+ and Ge 4+ cations tend to segregate in the vicinity of the grain boundaries in the TZP-sintered bodies. The TZP and Ge 4+-doped TZP exhibited an elongation to failure of more than 100% in the temperature range of 1150°C-1300°C and initial strain rate range of 1.4 × 10 -5 s -1 to 1.0 × 10 -2 s -1. For instance, an elongation to failure in the Ge-doped TZP reached about 200% at 1150°C and 1.4 × 10 -5 s -1. The nanocrystallization reduced the lower limit of the superplastic temperature of conventional, submicron-grain TZP materials by 150°C. The improved ductility of the TZP at low temperatures was essentially attributed to the reduced grain size.
AB - Nanocrystalline tetragonal ZrO 2 polycrystals (TZP) have been fabricated by the pressureless sintering of recently developed tetragonal ZrO 2 powder containing 5.69 mol% YO 1.5 and 0.60 mol% AlO 1.5. The average grain sizes were 160 nm in the TZP sintered at 1150°C for 10 h and 150 nm in the 0.25 mol% GeO 2-doped TZP sintered at 1100°C for 100 h. The TZP and Ge 4+-doped TZP-sintered bodies were essentially single-phase materials, and neither the amorphous layer nor the second-phase particle was observed along the grain boundary faces. High-resolution transmission electron microscopy (HRTEM), scanning transmission electron microscopy (STEM), and nanoprobe energy-dispersive X-ray spectrometer (EDS) measurements revealed that the Y 3+, Al 3+ and Ge 4+ cations tend to segregate in the vicinity of the grain boundaries in the TZP-sintered bodies. The TZP and Ge 4+-doped TZP exhibited an elongation to failure of more than 100% in the temperature range of 1150°C-1300°C and initial strain rate range of 1.4 × 10 -5 s -1 to 1.0 × 10 -2 s -1. For instance, an elongation to failure in the Ge-doped TZP reached about 200% at 1150°C and 1.4 × 10 -5 s -1. The nanocrystallization reduced the lower limit of the superplastic temperature of conventional, submicron-grain TZP materials by 150°C. The improved ductility of the TZP at low temperatures was essentially attributed to the reduced grain size.
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U2 - 10.1111/j.1551-2916.2012.05150.x
DO - 10.1111/j.1551-2916.2012.05150.x
M3 - Article
AN - SCOPUS:84861194808
VL - 95
SP - 1701
EP - 1708
JO - Journal of the American Ceramic Society
JF - Journal of the American Ceramic Society
SN - 0002-7820
IS - 5
ER -