Anisotropy of Compressive Deformation Behavior in Cold Sprayed Cu Bulk Material

Area of Science:

• Materials Science
• Additive Manufacturing
• Mechanical Engineering

Background:

• Cold spray 3D printing (kinetic metallization) enables near-net shape manufacturing of bulk materials.
• Pure copper processed via cold spray exhibits unique microstructures with accumulated dislocations due to high-speed particle impacts.

Purpose of the Study:

• To investigate the anisotropy of compressive deformation behavior in pure copper manufactured by cold spray.
• To analyze the microstructural evolution under different strain conditions and directions (spraying vs. perpendicular).

Main Methods:

• Compressive deformation testing along spraying and perpendicular directions.
• Microstructural analysis using Scanning Electron Microscopy (SEM), Field Emission SEM (FE-SEM), X-ray Diffraction (XRD), and Electron Backscatter Diffraction (EBSD).
• Fractographic observation to understand deformation and fracture mechanisms.

Main Results:

• Pure copper showed directional differences in mechanical properties: spraying direction yielded 330 MPa (YS) and 437 MPa (CPS), while the perpendicular direction showed 327 MPa (YS) and 422 MPa (CPS).
• Strain softening phenomena were observed at room temperature under low strain conditions due to dynamic recovery of dislocation structures.
• Microstructural analysis revealed significant dislocation accumulation and changes consistent with the observed anisotropy.

Conclusions:

• Cold spray processed copper exhibits significant anisotropy in compressive deformation behavior.
• The observed strain softening is attributed to dynamic recovery, influencing the material's mechanical response at different strain levels and directions.