Thermal property characterisation of additively manufactured copper as a function of sintering time

Clean Energy Research Group, Department of Mechanical and Aeronautical Engineering, University of Pretoria, South Africa

^* Corresponding author: bradley.bock@up.ac.za

Abstract

Recent advancements now allow for high thermal conductivity metals such as copper to be additively manufactured and will allow for the applications of the technology to be broadened in the field of heat transfer. In this study, copper samples were additively manufactured using bound powder extrusion (BPE) and thermally sintered and then characterised in terms of thermal conductivity and specific heat capacity. The sintering hold time was varied to determine the influence between the resulting change in porosity and the measured properties. For this study it was found that porosity is a function of sintering hold time and varies between 44 to 25% for a sintering hold time of between 0 to 20 hours. Specific heat capacity was found to not be a function of sintering hold time, but samples tested had a slightly lower specific heat capacity value than expected ranging from 380 to 360 J/kg/K. The copper thermal conductivity was significantly reduced by the process to between 35 to 73 W/mK. It was found to be a function of sintering hold time, and some empirical models can estimate this property relatively well.