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建立了含椭球形微孔的三维体胞,该模型包含了椭球形微孔的一种特例:即球形微孔。采用晶体塑性滑移理论对不同取向下,单晶合金铸造微孔形状对微孔生长和滑移系激活的影响进行了研究。结果表明,材料的晶体坐标系、椭球微孔坐标系和载荷坐标系之间的坐标转换角度以及椭球微孔的形状对于微孔的演化具有非常重要的影响。对于三维应变状态下,椭球微孔的形状、晶体取向与载荷之间的相互关系共同决定了铸造微孔体积的增长、滑移系的激活和微孔旋转。当单胞滑移系的对称性被椭球型微孔破坏,即使载荷与滑移系统具有对称性,铸造微孔也会发生旋转。虽然单晶合金具有强烈的正交各向异性,但是当铸造微孔初始形状不为球形时,材料性能的正交各向异性对铸造微孔体积增长的影响被削弱。
A three-dimensional body cell with ellipsoidal micropores is established. The model contains a special case of ellipsoidal micropores: spherical micropores. The effects of different shapes on the growth of micro-pores and the activation of slip system were investigated by using the theory of plastic plastic sliding. The results show that the crystal coordinate system, the coordinate transformation between ellipsoid and coordinate system, and the shape of ellipsoid micropore have a very important influence on the micropore evolution. For the three-dimensional strain state, the shape of the ellipsoid micropore, the relationship between the crystal orientation and the load jointly determine the growth of the micropore volume, the slip system activation and the micropore rotation. When the symmetry of the cell slip system is destroyed by ellipsoidal micropores, the cast micropores rotate even though the load is symmetrical with the slip system. Although the single crystal alloy has a strong orthorhombic anisotropy, the effect of the orthotropicity of the material properties on the growth of the micropores of the castings is weakened when the initial shape of the cast micropores is not spherical.