Experimental comparison of performance of CuCrZr microchannel heat sinks manufactured by selective laser melting and drilling

The ability to fabricate high-density, high-thermal-conductivity components with complex microchannel structures is critical in thermal management field. In this paper, the minimum forming diameter of the microchannel of CuCrZr alloy fabricated by the selective laser melting (SLM) was measured. Owing to high thermal conductivity and laser reflectivity, the microchannel structure of CuCrZr had higher internal surface roughness and bigger minimum forming diameter relative to that of other metals. The microchannel heat sinks manufactured by selective laser melting (SLM-MCHS) showed over 3 times the pressure drop of microchannel heat sinks manufactured by drilling process (DP-MCHS). The temperature difference between SLM-MCHS and DP-MCHS with 0.9 mm diameter reached 2.6 °C under the same heat source. Since the partial melted powder on the surface of channel acted as “turbulators”, destroying the thermal boundary layer, leading to an increase in heat transfer performance. The performance evaluation criterion of the SLM-MCHS is 1.19 in 0.9 mm diameter. For long-term stability measurement, the thermal transfer performance and the pressure drop of SLM-MCHS dropped to 98.3% and 99.0% in 5 days. This work demonstrated the feasibility and the limitation of fabricating copper-based microchannel heat sinks via SLM, while providing a fast and reliable experiment platform for water-cooled heat sinks.