Laser Powder Bed Fusion of Chromium Bronze Using Recycled Powder

Area of Science:

• Materials Science
• Additive Manufacturing
• Metallurgy

Background:

• Laser powder bed fusion (LPBF) is a key additive manufacturing technique.
• Utilizing recycled metal powders can reduce costs and environmental impact.
• Characterizing recycled powder is crucial for process repeatability.

Purpose of the Study:

• To investigate the feasibility of using recycled Cu-0.5Cr powder in LPBF.
• To analyze the effects of recycled powder on microstructure and defects.
• To evaluate the mechanical properties of LPBF-processed Cu-0.5Cr from recycled powder.

Main Methods:

• Laser powder bed fusion (LPBF) was performed using recycled Cu-0.5Cr powder.
• Powder characterization included particle size distribution analysis.
• LPBF process parameters were optimized to achieve high relative density.
• Microstructural analysis and mechanical property testing (tensile) were conducted.

Main Results:

• Recycled Cu-0.5Cr powder exhibited similar particle size distribution to virgin powder.
• LPBF of recycled powder led to increased spherical pore formation.
• Optimized LPBF parameters achieved a relative density of 99.2%.
• The microstructure consisted of an oversaturated dendritic Cu matrix with nano-sized Cr precipitations.
• Satisfactory mechanical properties were obtained: yield strength of 136.8 MPa, UTS of 187.4 MPa, and 15.5% elongation.

Conclusions:

• Recycled Cu-0.5Cr powder is viable for laser powder bed fusion.
• Process optimization can overcome challenges like pore formation from recycled powder.
• LPBF of recycled Cu-0.5Cr yields a microstructure with significant strengthening mechanisms and good mechanical performance.