Thermal conductivity of TPMS lattice structures manufactured via laser powder bed fusion

• Published in: Additive manufacturing Vol. 30; p. 100846
• Main Authors: Catchpole-Smith, S., Sélo, R.R.J., Davis, A.W., Ashcroft, I.A., Tuck, C.J., Clare, A.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.12.2019
• Subjects: Additive manufacture; Heat transfer; Laser powder bed fusion; Lattice structure; Nickel; Thermal conductivity; Titanium; TPMS; Laser powder bed fusion; TPMS; Titanium; Thermal conductivity; Nickel; Additive manufacture; Lattice structure; Heat transfer
• ISSN: 2214-8604; 2214-7810
• DOI: 10.1016/j.addma.2019.100846

Lattice structures can add value to high-performance components manufactured by laser powder bed fusion due to their high specific strength and stiffness. A further use of lattice structures is in thermo-mechanical applications, where the high surface area of the lattice may aid heat transfer. However, little characterisation of lattices under thermal loading is currently available in the literature. In this study, a custom-built test rig was used to characterise the thermal conduction for three triply periodic minimal surface lattice types, namely: gyroid, diamond and Schwarz primitives, with unit cell size and volume fraction being varied. Results show that thermal conductivity is primarily a function of the material properties and volume fraction of the sample. However, some effects of the geometry, such as surface area to volume ratio, can be used to explain slight differences in the measured conductivity. The Schwarz primitive unit cell consistently gave the highest conductivity, with diamond and gyroid unit cells being marginally lower. Larger cell sizes typically gave higher conductivity than smaller cells, which can be attributed to greater intra-cell convective heat transfer and better interface coupling with the testing apparatus. The experimental results are used to derive equations that allow samples with a specified thermal conductivity to be designed, thus demonstrating how a component may be manufactured with a custom thermal profile by varying the volume fraction of the lattice.