Quantitative representation of directional microstructures of single-crystal superalloys in cyclic crystal plasticity based on neural networks

• Published in: International journal of plasticity 2023-11, Vol.170, p.103757, Article 103757
• Main Authors: Weng, Huanbo, Yuan, Huang
• Format: Article
• Language: English
• Subjects: Crystal plasticity; Fabric tensor; Long short-term memory (LSTM); Neural network; Nickel-based superalloys; Rafting
• ISSN: 0749-6419
• DOI: 10.1016/j.ijplas.2023.103757

Nickel-based single-crystal alloys undergo microstructural degradation induced by thermal exposure. The directional rafting of microstructures significantly affects the mechanical properties and makes the material anisotropic. For structural design, establishing a quantitative description of microstructural effects in a constitutive model becomes essential and is still a tough research topic in multi-scale materials modeling. In the present work, the fabric tensor was correlated with the anisotropic cyclic crystal plasticity of nickel-based single-crystal alloys with the help of neural networks. The microstructural representative volume elements with various single-crystal morphologies were generated by the phase-field method and the deformation behaviors were studied under different crystal orientations and loading configurations. The neural network analysis confirmed that the fabric tensor can present anisotropic single-crystallographic microstructural features and describe mechanical behavior under both monotonic and cyclic multi-axial loading conditions. The history-dependent anisotropic cyclic hardening or softening behavior of the material can be captured by the introduced microstructural state variable. A principal component analysis (PCA) aided gradient-based attribution method was proposed to evaluate the importance of input variables. The characterization of different material components and their contribution to the stress–strain relationships are investigated and validated. The fabric tensor was verified to be an effective microstructural indicator for the continuum plasticity of single-crystal alloys. •Rafting microstructures of single-crystal alloys are represented by fabric tensors.•Anisotropic crystal behaviors are correlated with fabric tensors by neural networks.•The cosine components represent asymmetric crystallographic properties of alloys.•The PCA attribution reveals correlations of fabric tensors in constitutive modeling.