The relationship between the microstructural evolution mechanisms and the dynamic performance characteristics of polycrystalline Mg-3Al-1Zn alloy under high-speed impact loading has not been fully elucidated, necessitating further research.
Here, molecular dynamics (MD) simulations were used to systematically explore the shock-induced microstructural evolution mechanism of the Mg-3Al-1Zn alloy.
We analyzed the correlation between phase transition occurrence, dislocation slip, adiabatic temperature evolution, and their relationships with dynamic properties.
Our findings reveal that impact loading causes atomic position changes, transforming the microstructure into a highly disordered state.
This study elucidates the atomic-scale microstructural evolution characteristics of Mg-3Al-1Zn alloy under shock loading, providing in-depth insights into its dynamic performance.
The relationship between the microstructural evolution mechanisms and the dynamic performance characteristics of polycrystalline Mg-3Al-1Zn alloy under high-speed impact loading has not been fully elucidated, necessitating further research. Here, molecular dynamics (MD) simulations were used to systematically explore the shock-induced microstructural evolution mechanism of the Mg-3Al-1Zn alloy. We analyzed the correlation between phase transition occurrence, dislocation slip, adiabatic temperature evolution, and their relationships with dynamic properties. Our findings reveal that impact loading causes atomic position changes, transforming the microstructure into a highly disordered state. After the shock wave passes, the local stress concentration at the grain boundaries is absorbed, promoting the formation of numerous face-centered cubic (FCC) stacking faults and Shockley partial dislocations (SPDs) loops within the structure. The stacking faults (SFs) gradually transform into twins. The continuous generation and absorption of SPDs and SFs, along with the formation of twin, cause stress fluctuations during the deformation stage. The length of these dislocations initially increases but subsequently decreases due to absorption from grain boundaries and structural reconstruction. During the dynamic impact process, deformation leads to an increase in the alloy’s internal temperature, causing an adiabatic temperature rise that results in a sudden drop in material stress and a softening phenomenon. This study elucidates the atomic-scale microstructural evolution characteristics of Mg-3Al-1Zn alloy under shock loading, providing in-depth insights into its dynamic performance.
