Relationship between Σ3 Boundaries, Dislocation Slip, and Plasticity in Pure Nickel

Area of Science:

• Materials Science
• Metallurgy
• Solid Mechanics

Background:

• Grain boundaries (GBs) significantly influence material properties.
• Understanding GBs is crucial for tailoring mechanical behavior.
• Dislocation slip and plasticity are key deformation mechanisms in metals.

Purpose of the Study:

• Investigate the role of Σ3 boundaries in plastic deformation.
• Elucidate the relationship between GB modification, dislocation slip, and plasticity in pure nickel.
• Determine the impact of different boundary types on deformation coordination.

Main Methods:

• Quasi in situ tensile testing of pure nickel wires.
• Computational simulations of plastic deformation.
• Analysis of dislocation slip systems and stress accumulation.

Main Results:

• Σ3 boundaries exhibit good deformation coordination with twins and facilitate dislocation movement.
• Random boundaries strongly hinder dislocations, leading to stress accumulation.
• The dominant slip systems, particularly those involving (111) planes, remain consistent during deformation.
• Σ3 boundaries release stress and improve geometrical compatibility, enhancing overall plasticity.

Conclusions:

• GB modification, specifically introducing Σ3 boundaries, enhances plasticity in pure nickel.
• The unique structure of Σ3 boundaries promotes dislocation slip and improves deformation coordination.
• Findings offer insights into plasticizing mechanisms for face-centered cubic (fcc) materials.