Defect and Diffusion Forum Vol. 446

Abstract: In the present work artificial neural networks (ANN) models have been implemented and trained as surrogate models to replicate two physics-based microstructure models for Al-alloys, i.e. the ALFLOW model, which predicts the sub-structure evolution and associated flow stress during plastic deformation and the softening model ALSOFT, which predicts the softening behavior after hot/cold deformation, in view of the combined effect of recovery and recrystallization. Input for both ANN models was limited to variables such as strain, strain rate, time, temperature and solute concentration, and the flow stress as the output. Accuracy and efficiency were tested for different ANN architectures. It is demonstrated that fully connected feed-forward neural network architectures with ∼3 hidden layers are suitable as surrogate models for both ALFLOW and ALSOFT, with a potential speed-up of ∼100x for ALFLOW and ∼10x for ALSOFT.

Abstract: The sintering behavior of spark plasma sintering was analyzed by extracting features from process data obtained during the fabrication of aluminum matrix composites and machine learning using the obtained features were performed to predict relative density of composites. Seventy-five samples were sintered with different types of reinforcement, and different temperature and pressure conditions. Regression methods include linear regression such as Ridge, Lasso and Elastic Net, and nonlinear regression such as random forest, gradient boosting and XGBoost were tested. XGBoost had the highest prediction accuracy and the trained model was used for Shapley additive explanations value analysis and inverse analysis.

Abstract: The recent progress in theoretical, experimental, and computational studies of phase coarsening is briefly reported in this paper. The study of phase coarsening in materials processing is important to ensuring future improvements in a variety of industrial materials applications. The first successful theoretical description of diffusion-controlled phase coarsening in three-dimensional systems was proposed by Lifshitz and Slyozov in 1961, and independently, a theory for interface-reaction-controlled phase coarsening was developed by Wagner in 1961. In order to consider the effects of non-zero volume fraction on phase coarsening, recently, the author developed diffusion screening theory for the kinetics of phase coarsening. In the case of ultra-high volume fractions, the author’s diffusion layer theory was published in 2023. There are several advanced experimental methods developed to investigate and quantify the late-stage phase coarsening, including microgravity experiment on Space Shuttle and the International Space Station (ISS). Recently, phase field simulations for the study of phase coarsening have been performed for systems with different volume fractions.