单晶高温合金中铸造微孔洞的扩长

基于有限变形晶体塑性本构关系及轴对称体胞模型,采用有限元的方法,分析了在不同取向偏角及不同滑移系开动,单晶高温合金中铸造微孔洞扩长的力学行为。分析结果表明:取向偏角对铸造微孔洞的扩长具有重要的意义,但对铸造微孔洞的形状改变影响不大,为改善单晶高温合金热端部件的疲劳、蠕变性能,控制晶体的取向偏角是很必要的;滑移系族开动的类型对铸造微孔洞的扩长有很大的影响,这种影响与Schmid因子、加载的取向相关,为更加准确地分析单晶高温热端部件的寿命,确定滑移系族开动类型至关重要。

Casting Microporosity Growth Simulation in Single-Crystal Superalloys

Finite element analysis is employed to investigate casting microporosity behavior in nickel-base single-crystal superalloys.Based on finite deformation rate-dependent crystallographic constitutive equation,the growth simulation of casting microporosity in a unit cell model is carried out within a range of parameters including deviation orientation,type of different slip systems activated.The results show that the deviation orientation exerts remarkable effects on the growth behavior and volume fraction of casting microporosity,but the shape transform of casting microporosity is slightly affected.To ensure the performing safety of the single-crystal superalloy components,it is necessary to control the deviation orientation which may lead to the obvious change of casting microporosity volume during deformation.Similarily,it is important to determine the operative slip systems type associated with Schmid Factor and loading orientation to evaluate accurately the hot spot life.