Keshavarz Shahriyar, Campbell Carelyn E, Reid Andrew C E
Materials Science Division, Thermodynamics and Kinetics Group, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA.
Materials (Basel). 2022 Jun 24;15(13):4447. doi: 10.3390/ma15134447.
The current study focuses on the modeling of two-phase γ-γ' nickel-based superalloys, utilizing multi-scale approaches to simulate and predict the creep behaviors through crystal plasticity finite element (CPFE) platforms. The multi-scale framework links two distinct levels of the spatial spectrum, namely, sub-grain and homogenized scales, capturing the complexity of the system responses as a function of a tractable set of geometric and physical parameters. The model considers two dominant features of γ' morphology and composition. The γ' morphology is simulated using three parameters describing the average size, volume fraction, and shape. The sub-grain level is expressed by a size-dependent, dislocation density-based constitutive model in the CPFE framework with the explicit depiction of γ-γ' morphology as the building block of the homogenized scale. The homogenized scale is developed as an activation energy-based crystal plasticity model reflecting intrinsic composition and morphology effects. The model incorporates the functional configuration of the constitutive parameters characterized over the sub-grain γ-γ' microstructural morphology. The developed homogenized model significantly expedites the computational processes due to the nature of the parameterized representation of the dominant factors while retains reliable accuracy. Anti-Phase Boundary (APB) shearing and, glide-climb dislocation mechanisms are incorporated in the constitutive model which will become active based on the energies associated with the dislocations. The homogenized constitutive model addresses the thermo-mechanical behavior of nickel-based superalloys for an extensive temperature domain and encompasses orientation dependence as well as the loading condition of tension-compression asymmetry aspects. The model is validated for diverse compositions, temperatures, and orientations based on previously reported data of single crystalline nickel-based superalloy.
当前的研究聚焦于两相γ-γ'镍基高温合金的建模，利用多尺度方法通过晶体塑性有限元（CPFE）平台来模拟和预测蠕变行为。多尺度框架连接了空间谱的两个不同层次，即亚晶粒和均匀化尺度，将系统响应的复杂性作为一组易于处理的几何和物理参数的函数进行捕捉。该模型考虑了γ'形态和成分的两个主要特征。γ'形态通过描述平均尺寸、体积分数和形状的三个参数进行模拟。亚晶粒层次由CPFE框架中基于位错密度的尺寸相关本构模型表示，其中γ-γ'形态的明确描述作为均匀化尺度的构建块。均匀化尺度被开发为基于激活能的晶体塑性模型，反映内在成分和形态效应。该模型纳入了基于亚晶粒γ-γ'微观结构形态表征的本构参数的功能配置。所开发的均匀化模型由于主导因素的参数化表示性质显著加快了计算过程，同时保持了可靠的精度。反相界（APB）剪切以及滑移-攀移位错机制被纳入本构模型，它们将根据与位错相关的能量而激活。均匀化本构模型解决了镍基高温合金在广泛温度范围内的热机械行为，涵盖了取向依赖性以及拉伸-压缩不对称方面的加载条件。基于先前报道的单晶镍基高温合金数据，该模型针对不同的成分、温度和取向进行了验证。
