The composites were prepared by ball-milling ZrO_2(3%Y_2O_3) and γ-Al_2O_3 nanoparticles, pressing unidirectionally, cold-pressing isostatically and pressurelessly sintering in air. The phases of ZrO_2 in composites ...The composites were prepared by ball-milling ZrO_2(3%Y_2O_3) and γ-Al_2O_3 nanoparticles, pressing unidirectionally, cold-pressing isostatically and pressurelessly sintering in air. The phases of ZrO_2 in composites were examined by X-ray diffraction. The microstructure of Al_2O_3/3Y-TZP composites was observed by scanning electron microscope (SEM) and transmission electron microscopy (TEM) respectively. The X-ray analysis reveals that ZrO_2 of both surface and fracture surface is mainly t-ZrO_2. The SEM image shows that there are some intragranular particles in large granulars. The fracture toughness K_ 1c of Al_2O_3/70%ZrO_2(3%Y_2O_3(mole fraction)) composite tested by single-edge notched bending is 13.5 MPa·m 1/2. Being toughened by the ferroelastic domain switching and the intragranular microstructure explains high toughness of the composite.展开更多
Nanometer 3Y TZP/20%Al 2O 3 (mass fraction) composite powders prepared by the chemical coprecipitation method were pressureless sintered at 1550 ℃ for 2 h. Effects of calcining temperatures at 800 ℃, 1 000 ℃, and 1...Nanometer 3Y TZP/20%Al 2O 3 (mass fraction) composite powders prepared by the chemical coprecipitation method were pressureless sintered at 1550 ℃ for 2 h. Effects of calcining temperatures at 800 ℃, 1 000 ℃, and 1 200 ℃ on phase structure, relative density, and Vicker′s hardness of the sintered bodies were studied. The results show that 1 000 ℃ was the optimal calcining temperature,and the powder calcined was composed of tetragonal zirconia with the Scherrer crystalline size of 6.3 nm. The relative density was up to 98.5% under pressureless sintering, and the sintered body was t ZrO 2(without m ZrO 2)+α Al 2O 3 with the average size of 0.4 μm.展开更多
通过 SiC 晶须与 Y-TZP 的复合,观察了 SiC 晶须的加入对 Y-TZP 基体相组成的影响。当 SiC 晶须长度缩短后,晶须在基体中分布的均匀性得到改善,复合材料的力学性能明显提高。Y-TZP 与 SiC 晶须复合后,室温性能降低,但材料的高温强度有...通过 SiC 晶须与 Y-TZP 的复合,观察了 SiC 晶须的加入对 Y-TZP 基体相组成的影响。当 SiC 晶须长度缩短后,晶须在基体中分布的均匀性得到改善,复合材料的力学性能明显提高。Y-TZP 与 SiC 晶须复合后,室温性能降低,但材料的高温强度有所改善,10 Vol%SiC 晶须/Y-TZP 复合材料在800℃时的强度为440MPa,材料的抗热震性也有明显改善。展开更多
文摘The composites were prepared by ball-milling ZrO_2(3%Y_2O_3) and γ-Al_2O_3 nanoparticles, pressing unidirectionally, cold-pressing isostatically and pressurelessly sintering in air. The phases of ZrO_2 in composites were examined by X-ray diffraction. The microstructure of Al_2O_3/3Y-TZP composites was observed by scanning electron microscope (SEM) and transmission electron microscopy (TEM) respectively. The X-ray analysis reveals that ZrO_2 of both surface and fracture surface is mainly t-ZrO_2. The SEM image shows that there are some intragranular particles in large granulars. The fracture toughness K_ 1c of Al_2O_3/70%ZrO_2(3%Y_2O_3(mole fraction)) composite tested by single-edge notched bending is 13.5 MPa·m 1/2. Being toughened by the ferroelastic domain switching and the intragranular microstructure explains high toughness of the composite.
文摘Nanometer 3Y TZP/20%Al 2O 3 (mass fraction) composite powders prepared by the chemical coprecipitation method were pressureless sintered at 1550 ℃ for 2 h. Effects of calcining temperatures at 800 ℃, 1 000 ℃, and 1 200 ℃ on phase structure, relative density, and Vicker′s hardness of the sintered bodies were studied. The results show that 1 000 ℃ was the optimal calcining temperature,and the powder calcined was composed of tetragonal zirconia with the Scherrer crystalline size of 6.3 nm. The relative density was up to 98.5% under pressureless sintering, and the sintered body was t ZrO 2(without m ZrO 2)+α Al 2O 3 with the average size of 0.4 μm.
文摘通过 SiC 晶须与 Y-TZP 的复合,观察了 SiC 晶须的加入对 Y-TZP 基体相组成的影响。当 SiC 晶须长度缩短后,晶须在基体中分布的均匀性得到改善,复合材料的力学性能明显提高。Y-TZP 与 SiC 晶须复合后,室温性能降低,但材料的高温强度有所改善,10 Vol%SiC 晶须/Y-TZP 复合材料在800℃时的强度为440MPa,材料的抗热震性也有明显改善。
