Casting microporosity growth in single-crystal superalloys by a three-dimensional unit cell analysis
Casting microporosity growth in single-crystal superalloys by a three-dimensional unit cell analysis
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DOI：
10.1088/0965-0393/13/6/007
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发表时间：
2005-09
影响因子：
1.8
通讯作者：
J S Wan;Z F Yue;Z. Z. Lu-Z.
中科院分区：
文献类型：
--
作者：
J S Wan;Z F Yue;Z. Z. Lu-Z.
采用有限元分析方法研究了镍基单晶高温合金DD 3的铸态气孔生长过程。基于有限变形速率相关的晶体学本构方程，在三维单胞模型中模拟了不同三轴度、矿脉参数、不同滑移系激活和加载方向等参数对铸件微观疏松的影响。结果表明，应力三轴度对铸件微气孔的生长行为、体积分数和形状转变有显著影响;矿脉参数是影响铸件微气孔生长和形状转变的重要参数，也是影响铸件微气孔三轴度的重要参数。铸件微气孔周围较大的局部累积剪应变对铸件微气孔的长大起着重要的驱动作用，铸件微气孔体积分数越高，累积剪应变越大。滑移系类型和加载方向对铸件微孔的生长有显著影响，并与Schmid因子和杨氏取向模量有关。
Finite element (FE) analysis is employed to investigate casting microporosity growth in nickel-base single-crystal superalloys DD3. Based on a finite deformation rate-dependent crystallographic constitutive equation, the simulation of casting microporosity in a three-dimensional unit cell model was carried out under variation in a range of parameters including triaxiality, Lode parameter and a type of different slip systems activated and loading orientation. The FE results show that the stress triaxiality has profound effects on growth behaviour, volume fraction of casting microporosity and shape transition; the Lode parameter is an important parameter for casting microporosity growth and shape transition as well as triaxiality. Large local cumulative shear strain around casting microporosity plays an important role in driving casting microporosity growth; the high casting microporosity volume fraction corresponds to big cumulative shear strain. The operative slip systems type and loading orientation has a remarkable effect on casting microporosity growth, which is associated with the Schmid Factor and the Young's modulus of orientation.