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

## TL;DR

This paper explores using high-nickel Cu-Ni-Si powders in laser 3D printing to improve material strength and conductivity.

## Contribution

A novel powder-based approach enables higher Ni content in Cu-Ni-Si alloys for laser powder bed fusion.

## Key findings

- Gas-atomized powders with high Ni content showed fine microstructure and limited segregation.
- Increased Ni content improved hardness and optical response in the printed alloys.
- High-Ni Cu-Ni-Si compositions are viable for laser powder bed fusion with enhanced properties.

## Abstract

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.