陶瓷材料高温断裂韧性评价

The Evaluation of Fracture Toughness for SiC Ceramic at Elevated Temperatures

采用四点弯曲实验方法 ,研究了高温下不同测试方法 (CN法、SENB法和 SEPB法 )对工业用重结晶 Si C陶瓷材料断裂韧性的影响。通过实验发现 :在低温下 (T<80 0℃ ) ,不同测试方法所获得的 KIC 不同 ,CN法测得 KIC 偏大 ,而 SEPB法测得的 KIC 则偏小 ,同时 ,三种测试方法获得的 KIC 随温度的升高变化率都不明显。在高温下(T >80 0℃ ) ,不同的测试方法其 KIC 随温度的升高变化趋势不同 ,CN法 KIC 随温度的升高而增大 ,SENB法 KIC 随温度的升高而减小 ,SEPB法

WT5BZ]The influence of different testing methods (CN, SENB and SEPB) on fracture toughness K IC of recrystallized SiC ceramic at elevated temperatures has been investigated by four point bending method. The result indicate that K IC is various corresponding to different testing methods, at lower temperatures, the K IC for CN is bigger , while that is smaller for SEPB. When T<800℃, the fracture toughness of SiC changes unapparently with increasing temperatures for different testing methods; when T>800℃, the fracture toughness shows different trend with increasing temperatures: the K IC for CN increases and it decreases for SENB, but it exhibits no change for SEPB with increasing temperatures.