Y_2O_3－ZrO_2陶瓷的高温动态疲劳特性

HIGH TEMPERATURE DYNAMIC FATIGUE BEHAVIOR OF Y2O3-ZrO2 CERAMICS

采用三点弯曲法测定了Ｙ２Ｏ３－ＺｒＯ２陶瓷在动态疲劳条件下的裂纹扩展参数与温度的关系．结果表明：相变增韧陶瓷（３Ｙ）的裂纹扩展参数ｎ及ｌｎＢ随温度的升高而单调下降，而非相变增韧陶瓷（２Ｙ与６Ｙ）的ｎ值在室温～９００℃之间随温度的升高而上升，高于９００℃时下降，由此证实，温度对相变增韧陶瓷的弱化作用比强度及韧性变化所表征的更为严重．

Subcritical crack growth parameters,n and 1nB,as a function of temperature were mea-sured for three ceramics by three-point bending dynamic fatigue method.Crack growth pa-rameters of transformation toughening ceramics(3Y)decrease with the increase of tempera-ture and those of non-transformation toughening ceramics(2Y and 6Y)increase with the in-crease of temperature until temperature is up to 900℃.These demonstrate that the ransfor-mation toughening ceramics weakening with temperature is more serious than that character-ized by the decrease of strengh,and toughness.