Laser powder bed fusion of bronze - Process optimization and influence on microstructure and mechanical properties

Paper in proceeding, 2019

As the interest in additive manufacturing increases, so does the demand for new materials. Among these are the copper alloys due to their good bearing properties, corrosion resistance and electrical conductivity. When attempting to print Cu-base materials with laser powder bed fusion, their low laser absorption and high thermal conductivity restricts the attainable local heat absorption in the material and hence the manufacturability with respect full density processing, especially for pure Cu. Alloyed Cu constitutes, however, less challenge in this respect. Hence, spherical gas atomized bronze (Cu-11Sn) powder was used and all printing was performed in an EOS M100 machine in argon atmosphere. Design of experiment method was used to determine optimized process parameters with respect to laser power, scan speed and hatch distance. Full density (99.9%) parts were successfully fabricated with UTS>400 MPa and the fine cellular microstructure was displayed. Furthermore, thin wall capacity of 150 µm was demonstrated.