First-Principles Calculations of Oxygen-Dislocation Interaction in Magnesium

Area of Science:

• Materials Science
• Computational Materials Science
• Physical Metallurgy

Background:

• Magnesium (Mg) alloys are crucial for lightweight applications.
• Understanding solute interactions with dislocations is key to improving Mg deformation behavior.
• Interstitial solutes significantly influence mechanical properties.

Purpose of the Study:

• To investigate the interaction between interstitial oxygen atoms and alpha-type screw dislocations in Mg.
• To elucidate the effect of oxygen solutes on the deformation behaviors of Mg.
• To provide fundamental knowledge for alloying Mg using interstitial solutes.

Main Methods:

• First-principles calculations were employed to model atomic interactions.
• Analysis focused on the energetics and configurations of dislocation cores in the presence of oxygen.
• Simulations explored the influence of oxygen on basal and prismatic slip systems.

Main Results:

• Repulsive interactions were observed between basal screw dislocation cores and oxygen atoms.
• Oxygen atoms increase resistance to the motion of dissociated basal dislocations.
• The presence of oxygen reduces the energy of prismatic alpha-type screw dislocation cores, stabilizing them and facilitating prismatic slip.

Conclusions:

• Oxygen solutes significantly alter the deformation mechanisms in magnesium.
• The findings provide insights into controlling Mg deformation via interstitial alloying.
• This study complements the fundamental understanding of Mg alloy design.