微观结构对 Si_3N_4 材料静疲劳特性的影响

选择两种不同添加剂的Ｓｉ３Ｎ４材料，研究了微观结构对其静疲劳特性的影响。结果发现，两种材料在不同介质中的静疲劳特性一致，即裂纹扩展速率在水中最大，空气中次之，煤油中最小。但由于添加ＺｒＯ２的材料独特的微观结构，使其具有较高的断裂韧性，因而裂纹扩展抗力较大，在相同应力水平条件下，寿命较长。

EFFECT OF MICROSTRUCTURE ON STATIC FATIGUE BEHAVIOUR OF Si 3N 4

Effect of microstructure on two kinds of materials containing different sintering aids on their static fatigue behaviour was studied. The results show that the static fatigue behaviour of the two materials is consistent with each other in various sorts of medium, i.e., the rate of crack growth of both materials is the biggest in water, then in air, and the lowest in kerosene. But the N2 material has the higher crack propagation resistence because of its higher fracture toughness caused by its distinctive microstructure, so it has the longer lifetime at the same stress level.