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Processing of Bulk Nanocrystalline Metals at the US Army Research Laboratory
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Diffusion Behavior and Fracture Mechanism at Solid-Liquid Interface of Polycrystalline Al/Mg Bimetallic System: A
Xiaoqiong Wang1, Jingfan Cheng2, Guangyu Li1
1School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024, China.
Materials (Basel, Switzerland)
|March 14, 2026
Summary
Molecular dynamics simulations reveal how pouring and preheating temperatures affect Al/Mg bimetallic composites. Higher temperatures increase diffusion and interfacial layer thickness, influencing fracture mechanisms and optimizing tensile strength.
Area of Science:
- Materials Science
- Computational Materials Science
- Metallurgy
Background:
- Al/Mg bimetallic composites are crucial for lightweight applications in aerospace and automotive industries.
- Interfacial behavior is key to the performance and reliability of these composites.
Purpose of the Study:
- To investigate the impact of pouring and preheating temperatures on interfacial diffusion and fracture mechanisms in Al/Mg bimetallic systems using molecular dynamics simulations.
- To identify optimal preparation parameters for enhanced material properties.
Main Methods:
- Molecular dynamics (MD) simulations were performed.
- Systematic variation of pouring temperatures (923 K, 973 K, 1023 K) and preheating temperatures (373 K, 473 K, 573 K).
- Analysis of interfacial diffusion behavior and tensile fracture mechanisms.
Main Results:
- Pouring and preheating temperatures consistently influence interfacial diffusion; Mg diffusion coefficient is higher than Al, while Al diffusion distance is greater.
- Increasing temperatures lead to a thicker interfacial transition layer.
- Pouring temperature affects fracture mode (dislocation to dislocation-twin mediated), while preheating temperature does not alter the dislocation-controlled mechanism.
- Fracture consistently occurs at the interface between the diffusion layer and the Mg matrix.
- Optimal tensile strength of 1.850 GPa achieved at 923 K pouring and 473 K preheating temperatures, a 52% improvement.
Conclusions:
- Temperature parameters significantly impact interfacial diffusion and fracture behavior in Al/Mg systems.
- Understanding these relationships allows for rational optimization of preparation parameters.
- This study provides theoretical insights into Al/Mg bimetallic system fracture mechanisms.
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