Dual-metal laser powder bed fusion of iron- and cobalt-based alloys

Abstract

A dual-metal laser powder bed fusion (LPBF) of cobalt-chrome‑molybdenum-based superalloy and maraging steel has been carried out using an EOS M290 machine. The ideal orientations of the dual-metal material were established using an electron backscatter diffraction (EBSD) technique. Three sections were analyzed: a) the cobalt-based alloy area, b) the iron-based alloy area, and c) the interface between the iron- and cobalt-based alloys. A strong 〈110〉||building direction (BD) fiber texture dominates the cobalt-based material, while the iron-based alloy exhibits 〈111〉||BD and 〈100〉||BD fiber textures. The texture in the interface changes from 〈100〉||BD at the bottom of the interface (close to maraging steel section) to <110>||BD at the top section (near the cobalt-chrome‑molybdenum-based superalloy section). Moreover, the diffusion calculations suggest a negligible diffusion depth in the interface, which avoids any possible formation of detrimental intermetallics. The information from this work can be utilized to control the texture of the dual-metal LPBF material to optimize various physical and mechanical properties while ensuring that no unwanted solid solution alloying takes place along the interface.