Laser powder bed fusion of electrically/thermally conductive component by developing inert Cr2O3-coated Cu powder

Abstract

To enhance the compatibility of Cu with laser powder bed fusion, pre-alloying or powder surface modification of introducing high laser-absorbing alloying elements is currently adopted. However, this only addresses the densification issue but sacrifices the more important electrical/thermal performance because of their supersaturated solid solution in Cu. A secondary heat treatment is required though it is highly risky in damaging the dimension of geometrically complex component. Here, a novel strategy of employing the high laser-absorbing inert Cr2O3 instead of solid-solution alloying elements for powder surface coating was effective in achieving the desired synergy of densification (99.5%) and electrical/thermal conductivity (91.8% IACS and 371 W m−1 K−1), by which no additional heat treatment is needed. A heat sink was built to verify these positive effects. The electrical/thermal conductivity obtained is equal to those for the printed Cu alloys after long-term heat treatment. This strategy is universally applicable to other inert candidates.