Effect of High Ni Content in Gas-Atomized Cu-Ni-Si Powders for Laser Powder Bed Fusion

Cu-Ni-Si alloys are advanced materials for electronic applications combining high mechanical strength and electrical conductivity through precipitation of fine Ni silicides. Increasing the Ni content-and, thus, the Ni:Si ratio-enhances the volume fraction of strengthening precipitates. However, the conventional fabrication route is time-consuming and costly, as the slow cooling rates lead to a coarse microstructure and pronounced segregation, limiting Ni and Si content to 5 wt.%. Rapid solidification techniques offer a promising alternative, since the higher cooling rates refine the microstructure while suppressing the elemental segregation. This study presents a novel powder-based approach to overcome the compositional limitations of Cu-Ni-Si alloys, providing a pathway for faster alloy screening. Two gas-atomized powders with different Ni contents-CuNi3Si1.5 and CuNi10Si1.5 (wt.%)-were engineered as feedstock for laser powder bed fusion, produced, and characterized to assess the effect of the Ni level on the microstructure and properties. Gas-atomization yielded spherical powders with a fine dendritic structure and limited segregation. Increased Ni content enhanced strengthening mechanisms and hardness, as well as improved optical response, suggesting the potential of high-Ni Cu-Ni-Si compositions for use in laser powder bed fusion.