LIU Dong rong, REN Ying, GUO Er jun. Numerical Simulation of Freckle Defects in Nickel based Superalloys[J]. 2020, 25(2): 118-124.DOI: 10.15938/j.jhust.2020.02.016.
镍基高温合金雀斑缺陷数值模拟
摘要
摘要:为深入理解镍基高温合金定向凝固过程中雀斑缺陷的演化特点,基于SIMPLE(semiimplicitmethod for pressure linked equations)算法,采用流体力学三大方程计算模拟研究CMSX2合金定向凝固过程中雀斑形成。借助文献中模拟结果验证模型,考察了几何形状和合金成分对铸件凝固过程中的流场、固相分数场及溶质偏析分布的影响。模拟结果表明:带有收缩截面的铸件形状易促进雀斑产生。铸件合金成分中Al元素会促进雀斑形成,而Ta元素则对抑制雀斑形成起到了较好作用。
Abstract
Abstract:In order to deeply understand the formationcharacteristics of freckle defects in the process of directional solidificationof nickelbased superalloy
three major equations of fluid mechanics were usedto simulate the formation of freckles during the directional solidification ofCMSX2 superalloy based on the SIMPLE (SemiImplicit Method for Pressure LinkedEquations) algorithm The simulations in the reference were used to validate themodel The effects of geometric shape and alloy composition on the flow field
solid fraction field and solute segregation distribution during solidificationof the casting were investigated The simulations show that freckles are easilyformed in the casting with shrinkage section The Al element in the alloycomposition promotes the formation of freckles
while the Ta element plays avery good role in suppressing the formation of freckles