FGH95粉末冶金高温合金损伤与断裂特性研究

Damage and Fracture Speciality of FGH95 Powder Superalloy

观察分析FGH95粉末冶金高温合金高周疲劳光滑试样断口,研究其断裂规律;并用断口定量的方法对试样断口的裂纹扩展特性进行分析,计算疲劳扩展第2阶段的疲劳扩展寿命,并分析裂纹扩展特性与断裂特征的内在关系。针对120个试样用统计归纳的方法研究总寿命Nf与断裂特征参数ac之间的关系。临界裂纹长度取常用对数后与试验寿命取常用对数后具有大致线性关系,数据点分布在大致平行的具有一定宽度的分散带内,通过拟合出平行带的上下边界方程,可以给出寿命预测的上下边界方程,可用临界裂纹长度估算FGH95粉末冶金高温合金的疲劳寿命。

The fracture characteristics of high cycle fatigue slick samples of FGH 95 powder superalloy was observed, and the fracture feature law was put forward. The fatigue crack expanding peculiarity was analyzed using fractography quantitative analysis, and the fatigue expanding life was also calculated. On the basis of above research work, the internal relation between crack expanding peculiarity and fracture characteristics was analyzed. For 120 high cycle fatigue slick samples, the relation between fracture feature parameter ac and test fatigue life Nf was studied through statistical and inductive method. There is rough linear relation between loga~ and logNf, all of the data under the same temperature and stress ration R distribute among a disrupt strap with a certain width, and there are a top limit and below limit for the disrupt strap, the top limit line is approximately parallel to the below limit line. The critical crack length ac maybe used to evaluated the fatigue life using the top limit and below limit equations.