Deep potential driven molecular dynamics simulations on tensile properties of nano-grained Al–Ce alloys: Mechanisms of Ce segregation and strengthening

Micro-alloying with the rare-earth element Ce offers a promising approach to improving the mechanical properties of Al alloys. To gain atomic-level insights into how Ce micro-alloying influences the mechanical behavior of Al-based alloys, molecular dynamics (MD) simulations are essential. However, the scarcity of reliable potentials for Al-Ce systems has limited the application of MD simulations. This study focuses on developing a high-accuracy deep potential (DP) model for Al-Ce systems via the Deep Potential Generator (DP-GEN) active learning framework, and subsequently employs large-scale MD simulations to examine the impact of Ce content and segregation behavior on the mechanical properties of nano-grained Al alloys. The developed DP model exhibited strong generalization capability, accurately predicting lattice parameters, elastic properties, and phase transformation temperatures. We used this model to perform systematic MD simulations to analyze the mechanical response of nano-grained Al-Ce alloys under tensile deformation. The results indicate that the addition of Ce enhances the yield strength of the alloy, with a maximum improvement of 7.51% compared to pure Al achieved at a Ce content of 0.0195 at.%. Beyond this concentration, further Ce addition softens the alloy. This trend agrees well with experimental results, where the peak strength was observed at ∼0.02 at.% Ce. Furthermore, the yield strength increases significantly after MC annealing. These findings offer valuable insights into the atomic-scale mechanisms underlying the mechanical behavior of Al-Ce alloys and are also conductive to the composition design and property optimization of Al-Ce alloys.