Thermal conductivity of Cu7.2Ni1.8Si1Cr copper alloy produced via SLM and ability of thin-wall structure fabrication

Abstract

Selective Laser Melting (SLM) as part of the Additive manufacturing industry is a metal printing technology that is considered promising to address the thermal integrity defects of a Heat Switch – the space technology currently under development. However, no thermal conductivity data of SLMed copper alloy Cu7.2Ni1.8Si1Cr are freely available. Therefore, three parts were fabricated and tested in an experimental thermo-vacuum chamber to reveal the material thermal conductivity. The samples analogous to the Heat Switch components were: a disk with inner holes and two cylinders with thin-wall web of 0.325 mm and 1.625 mm. Based on the previous experience with the copper alloy, fabrication was successfully processed with up to 5 % dimensional accuracy according to CAD model. The thermal conductivity evaluation process was improved by the implementation of heat transfer by radiation and the calculated thermal conductivity of SLMed Cu7.2Ni1.8Si1Cr was 3.4 times lower than the value of bulk material AMPCOLOY 944 with a similar chemical composition.