摘要:
通过响应面法研究了升温速率、热处理温度和保温时间对Al2O3陶瓷断裂韧性的影响并确定了最佳热处理工艺, 分析了最佳工艺热处理后该陶瓷的性能和显微结构。结果表明:随着热处理温度的升高和保温时间的延长, Al2O3陶瓷断裂韧度先升后降, 各因素对断裂韧度的影响由大到小依次为热处理温度、保温时间、升温速率; 温度和保温时间的交互作用对断裂韧度的影响最大, 其次为升温速率和温度交互作用的, 升温速率和保温时间交互作用的影响最小; 最佳热处理参数为升温速率4 ℃·min-1、温度1 150 ℃、保温时间230 min, 在该条件下热处理后Al2O3陶瓷的断裂韧度由未热处理的3.25 MPa·m1/2提高到5.1 MPa·m1/2, 晶粒尺寸均匀、晶间缺陷及气孔数量减少。
Abstract:
The influences of the heating rate, heat treatment temperature and holding time on the fracture toughness and microstructures of Al2O3 ceramics were studied by the response surface method and the optimum heat treatment process was determined. The properties and microstructure of the ceramic after heat treatment with the optimum process were analyzed. The results show that with the increase of the heat treatment temperature and holding time, the fracture toughness of Al2O3 ceramics first increased then decreased. The factors, in order of effect significance, were ranked as follows: heat treatment temperature, holding time and heating rate. The effect of interaction between temperature and holding time on the fracture toughness was the biggest, followed by the interaction between heating rate and temperature and that between heating rate and holding time had the smallest influence. The optimum heat treatment parameters were found as follows: heating rate of 4 ℃·min-1, temperature of 1 150 ℃ and holding time of 230 min. After heat treated under this condition, the fracture toughness of the Al2O3 ceramic improved from 3.25 MPa·m1/2 before heat treatment to 5.1 MPa·m1/2. The grain sizes were uniform and internal defects and pore amounts were decreased.
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